TW202402562A - Bicycle hub assembly - Google Patents

Abstract

A bicycle hub assembly comprises a sprocket support body. The sprocket support body includes at least ten external spline teeth configured to engage with a bicycle rear sprocket assembly. Each of the at least ten external spline teeth has an external-spline driving surface and an external-spline non-driving surface.

Description

Bicycle wheel hub assembly

The invention relates to a bicycle wheel hub assembly.

Cycling is becoming an increasingly popular form of recreation as well as transportation. Furthermore, cycling has become a very popular competitive sport among both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving the various components of the bicycle. One bicycle component that has been fully redesigned is the wheel hub assembly.

According to a first aspect of the present invention, a bicycle wheel hub assembly includes a sprocket support body. The sprocket support body includes at least ten external spline teeth structured to engage a bicycle rear sprocket assembly. Each of the at least ten external spline teeth has an external spline drive surface and an external spline non-drive surface. In the case of the bicycle wheel hub assembly according to the first aspect, the at least ten external spline teeth reduce the force applied to the at least ten external splines compared to a sprocket support body including nine or less external spline teeth. The rotational force of each of the teeth. This improves the durability of the sprocket support body and/or improves the freedom in selecting the material of the sprocket support body without reducing the durability of the sprocket support body. According to a second aspect of the invention, a bicycle hub assembly as in the first aspect is structurally designed such that a total number of the at least ten external spline teeth is equal to or greater than 20. In the case of the bicycle wheel hub assembly according to the second aspect, the at least twenty external spline teeth are further reduced to at least twenty as compared to a sprocket support body including nine or less external spline teeth. The rotational force of each of the external spline teeth. This further improves the durability of the sprocket support body and/or improves the freedom in selecting the material of the sprocket support body without reducing the durability of the sprocket support body. According to a third aspect of the invention, a bicycle hub assembly as in the second aspect is structurally designed such that the total number of the at least ten external spline teeth is equal to or greater than 25. In the case of the bicycle wheel hub assembly according to the third aspect, compared to a sprocket support body including nine or less external spline teeth, the at least twenty-five external spline teeth further reduces the applied force to at least twenty The rotational force of each of the five external spline teeth. This further improves the durability of the sprocket support body and/or improves the freedom in selecting the material of the sprocket support body without reducing the durability of the sprocket support body. According to a fourth aspect of the present invention, the bicycle wheel hub assembly of any one of the first to third aspects is structurally designed such that the at least ten external spline teeth have a first external peripheral pitch angle and A second outer pitch angle that is different from the first outer pitch angle. In the case of the bicycle wheel hub assembly according to the fourth aspect, the difference between the first outer pitch angle and the second outer pitch angle helps the user to correctly install the bicycle rear sprocket assembly to the sprocket support body , especially regarding the circumferential position of each sprocket of the bicycle rear sprocket assembly. According to a fifth aspect of the present invention, the bicycle wheel hub assembly of any one of the first to fourth aspects is structurally designed such that at least one of the at least ten external spline teeth has a function different from that of the A first spline shape of another one of the at least ten external spline teeth and a second spline shape. In the case of the bicycle wheel hub assembly according to the fifth aspect, the difference between the first spline shape and the second spline shape helps the user to correctly install the bicycle rear sprocket assembly to the sprocket support body, especially It is about the circumferential position of each sprocket of the bicycle rear sprocket assembly. According to a sixth aspect of the present invention, the bicycle wheel hub assembly of any one of the first to fifth aspects is structurally designed such that at least one of the at least ten external spline teeth has a function different from that of the At least one of the other one of the ten external spline teeth is a second spline size and a first spline size. In the case of the bicycle wheel hub assembly according to the sixth aspect, the difference between the first spline size and the second spline size helps the user to correctly install the bicycle rear sprocket assembly to the sprocket support body, especially It is about the circumferential position of each sprocket of the bicycle rear sprocket assembly. According to a seventh aspect of the present invention, the bicycle wheel hub assembly of any one of the first to sixth aspects is structurally designed such that each of the at least ten external spline teeth has a maximum circumferential width. The sum of one of the largest circumferential widths is equal to or greater than 55 mm. In the case of the bicycle wheel hub assembly according to the seventh aspect, it is possible to improve the strength of at least ten external spline teeth in the shear direction. According to an eighth aspect of the present invention, the bicycle wheel hub assembly of the seventh aspect is structurally designed such that the sum of the maximum widths of the circumferences is equal to or greater than 60 mm. In the case of the bicycle wheel hub assembly according to the eighth aspect, it is possible to further improve the strength of at least ten external spline teeth in the shear direction. According to a ninth aspect of the present invention, the bicycle wheel hub assembly of the eighth aspect is structurally designed such that the sum of the maximum circumferential widths is equal to or greater than 65 mm. In the case of the bicycle wheel hub assembly according to the ninth aspect, it is possible to further improve the strength of at least ten external spline teeth in the shear direction. According to a tenth aspect of the present invention, a bicycle hub assembly includes a sprocket support body. The sprocket support body includes a plurality of external spline teeth structured to engage a bicycle rear sprocket assembly. At least two of the plurality of external spline teeth are circumferentially arranged at a first external pitch angle with respect to a central axis of rotation of the bicycle hub assembly. The first outer peripheral pitch angle is in the range of 10 degrees to 20 degrees. In the case of the bicycle hub assembly according to the tenth aspect, compared to the sprocket support body having an outer pitch angle greater than the first outer pitch angle, the first outer pitch angle reduction is applied to at least two outer The rotational force of each of the spline teeth. This improves the durability of the sprocket support body and/or improves the freedom in selecting the material of the sprocket support body without reducing the durability of the sprocket support body. According to an eleventh aspect of the present invention, the bicycle wheel hub assembly of the tenth aspect is structurally designed such that the first outer peripheral pitch angle is in the range of 12 degrees to 15 degrees. In the case of the bicycle hub assembly according to the eleventh aspect, compared to the sprocket support body having an outer pitch angle greater than the first outer pitch angle, the first outer pitch angle is further reduced to at least two The rotational force of each of the external spline teeth. This further improves the durability of the sprocket support body and/or improves the freedom in selecting the material of the sprocket support body without reducing the durability of the sprocket support body. According to a twelfth aspect of the present invention, the bicycle wheel hub assembly of the eleventh aspect is structurally designed such that the first outer peripheral pitch angle is in the range of 13 degrees to 14 degrees. In the case of the bicycle hub assembly according to the twelfth aspect, compared to the sprocket support body having an outer pitch angle greater than the first outer pitch angle, the first outer pitch angle is further reduced to at least two The rotational force of each of the external spline teeth. This further improves the durability of the sprocket support body and/or improves the freedom in selecting the material of the sprocket support body without reducing the durability of the sprocket support body. According to a thirteenth aspect of the present invention, the bicycle wheel hub assembly of any one of the tenth to twelfth aspects is structurally designed such that at least two of the plurality of external spline teeth The teeth are circumferentially arranged at a second outer circumferential pitch angle relative to the central axis of rotation of the bicycle hub assembly. The second outer pitch angle is different from the first outer pitch angle. In the case of the bicycle wheel hub assembly according to the thirteenth aspect, the difference between the first outer pitch angle and the second outer pitch angle helps the user to correctly install the bicycle rear sprocket assembly to the sprocket support The main body, especially the circumferential position of each sprocket of the bicycle rear sprocket assembly. According to a fourteenth aspect of the present invention, a bicycle wheel hub assembly includes a sprocket support body. The sprocket support body includes at least one external spline tooth structured to engage a bicycle rear sprocket assembly. The at least one external spline tooth has an external spline tip diameter equal to or less than 30 mm. In the case of the bicycle hub assembly according to the fourteenth aspect, the external spline top diameter enables the bicycle hub assembly to mount a bicycle rear sprocket assembly including a sprocket having ten sprocket teeth or less to Bicycle wheel hub assembly. This widens the gear range of the bicycle rear sprocket assembly mounted to the bicycle hub assembly. According to a fifteenth aspect of the present invention, the bicycle hub assembly of the fourteenth aspect further includes a brake rotor support body including at least one additional outer portion structured to engage a bicycle brake rotor. Spline teeth. The at least one additional external spline tooth has an additional external spline top diameter that is greater than the external spline top diameter. In the case of the bicycle hub assembly according to the fifteenth aspect, the brake rotor support body improves braking performance by widening the gear range of the bicycle rear sprocket assembly mounted to the bicycle hub assembly. According to a sixteenth aspect of the present invention, the bicycle wheel hub assembly of the fourteenth aspect or the fifteenth aspect is structurally designed such that the external spline top diameter is equal to or greater than 25 mm. In the case of the bicycle hub assembly according to the sixteenth aspect, it is possible to mount a bicycle rear sprocket assembly including a sprocket having ten or less sprocket teeth to the bicycle hub in such a manner that the bicycle hub assembly can In the case of the assembly, ensure the strength of the sprocket support body. According to a seventeenth aspect of the present invention, the bicycle rear hub assembly of the sixteenth aspect is structurally designed such that the external spline top diameter is equal to or greater than 29 mm. In the case of the bicycle hub assembly according to the seventeenth aspect, it is possible to mount a bicycle rear sprocket assembly including a sprocket having ten or less sprocket teeth to the bicycle hub in such a manner that the bicycle hub assembly can In the case of the assembly, ensure the strength of the sprocket support body. According to an eighteenth aspect of the present invention, the bicycle wheel hub assembly of any one of the fourteenth to seventeenth aspects is structurally designed such that the at least one external spline tooth has an external spline bottom diameter. , the base diameter of the external spline is equal to or less than 28 mm. In the case of the bicycle wheel hub assembly according to the eighteenth aspect, the bottom diameter of the external spline can increase the radial length of the transmission surface of at least one external spline tooth. This improved sprocket supports the strength of the main body. According to a nineteenth aspect of the present invention, the bicycle wheel hub assembly of the eighteenth aspect is structurally designed such that the bottom diameter of the external spline is equal to or greater than 25 mm. In the case of the bicycle hub assembly according to the nineteenth aspect, it is possible to reliably ensure the strength of the sprocket support body while widening the gear range of the bicycle rear sprocket assembly mounted to the bicycle hub assembly. According to a twentieth aspect of the present invention, the bicycle wheel hub assembly of the nineteenth aspect is structurally designed such that the bottom diameter of the external spline is equal to or greater than 27 mm. In the case of the bicycle hub assembly according to the twentieth aspect, it is possible to reliably ensure the strength of the sprocket support body while widening the gear range of the bicycle rear sprocket assembly mounted to the bicycle hub assembly. According to a twenty-first aspect of the present invention, the bicycle hub assembly of any one of the fourteenth to twentieth aspects is structurally designed such that the at least one external spline tooth includes a plurality of external splines. teeth, the plurality of external spline teeth including a plurality of external spline transmission surfaces for receiving a transmission rotational force from a rear sprocket assembly of the bicycle during pedaling. The plurality of external spline transmission surfaces each includes a radially outermost edge, a radially innermost edge, and a radial length defined from the radially outermost edge to the radially innermost edge. The sum of one of the radial lengths of the plurality of external spline transmission surfaces is equal to or greater than 7 mm. In the case of the bicycle wheel hub assembly according to the twenty-first aspect, it is possible to increase the radial length of the plurality of external spline transmission surfaces. This improved sprocket supports the strength of the main body. According to a twenty-second aspect of the present invention, the bicycle wheel hub assembly of the twenty-first aspect is structurally designed such that the sum of the radial lengths is equal to or greater than 10 mm. In the case of the bicycle wheel hub assembly according to the twenty-second aspect, it is possible to further increase the radial length of the plurality of external spline transmission surfaces. This further improves the strength of the sprocket support body. According to a twenty-third aspect of the present invention, the bicycle wheel hub assembly of the twenty-second aspect is structurally designed such that the sum of the radial lengths is equal to or greater than 15 mm. In the case of the bicycle wheel hub assembly according to the twenty-third aspect, it is possible to further increase the radial length of the plurality of external spline transmission surfaces. This further improves the strength of the sprocket support body. According to a twenty-fourth aspect of the present invention, the bicycle hub assembly of any one of the fourteenth to twenty-third aspects is structurally designed such that the sprocket support body includes a larger diameter portion, The larger diameter portion has an outer diameter greater than the outer spline tip diameter. In the case of the bicycle wheel hub assembly according to the twenty-fourth aspect, it is possible to improve the design freedom of the internal structure of the bicycle wheel hub assembly. For example, a transmission structure such as a one-way coupling structure may be accommodated within the internal cavity of this larger diameter portion of the sprocket support body. According to the twenty-fifth aspect of the present invention, the bicycle wheel hub assembly of the twenty-fourth aspect is structurally designed such that the outer diameter is in the range of 32 mm to 40 mm. In the case of the bicycle wheel hub assembly according to the twenty-fifth aspect, it is possible to further improve the design freedom of the internal structure of the bicycle wheel hub assembly. For example, it may be possible to easily place a transmission structure such as a one-way coupling structure within the internal cavity of this larger diameter portion. According to a twenty-sixth aspect of the present invention, the bicycle hub assembly of the twenty-fourth aspect further includes a hub axle including an axial contact surface for contacting a bicycle frame. The sprocket support body is rotatably mounted on the hub shaft around a rotation center axis. A first axial length is defined in an axial direction relative to the central axis of rotation from the axial contact surface to the larger diameter portion. The first axial length is in the range of 35 mm to 41 mm. In the case of the bicycle wheel hub assembly according to the twenty-sixth aspect, it is possible to ensure the axial length of at least one external spline tooth. According to a twenty-seventh aspect of the present invention, the bicycle wheel hub assembly of the twenty-sixth aspect is structurally designed such that the first axial length is equal to or greater than 39 mm. In the case of the bicycle wheel hub assembly according to the twenty-seventh aspect, it is possible to further ensure the radial length of at least one external spline tooth. According to a twenty-eighth aspect of the present invention, the bicycle wheel hub assembly of the twenty-sixth aspect is structurally designed such that the first axial length is in the range of 35 mm to 37 mm. In the case of the bicycle wheel hub assembly according to the twenty-eighth aspect, it is possible to further ensure the axial length of at least one external spline tooth. According to a twenty-ninth aspect of the present invention, the bicycle wheel hub assembly of the twenty-sixth aspect is structurally designed such that the larger diameter portion has a point farthest from the axial contact surface in the axial direction. axial end. A second axial length is defined in the axial direction from the axial contact surface to the axial end. The second axial length is in the range of 38 mm to 47 mm. In the case of the bicycle hub assembly according to the twenty-ninth aspect, it is possible to ensure the axial length of at least one external spline tooth while improving the design freedom of the internal structure of the bicycle hub assembly. According to a thirtieth aspect of the present invention, the bicycle wheel hub assembly of the twenty-ninth aspect is structurally designed such that the second axial length is in the range of 44 mm to 45 mm. In the case of the bicycle wheel hub assembly according to the thirtieth aspect, it is possible to further ensure the axial length of at least one external spline tooth and at the same time improve the design freedom of the internal structure of the bicycle wheel hub assembly. According to the thirty-first aspect of the present invention, the bicycle wheel hub assembly of the twenty-ninth aspect is structurally designed such that the second axial length is in the range of 40 mm to 41 mm. In the case of the bicycle wheel hub assembly according to the thirty-first aspect, it is possible to further ensure the axial length of at least one external spline tooth and at the same time improve the design freedom of the internal structure of the bicycle wheel hub assembly. According to a thirty-second aspect of the present invention, the bicycle wheel hub assembly of any one of the twenty-fourth to thirty-first aspects is structurally designed such that an axial length of the larger diameter portion is within Within the range of 3 mm to 6 mm. In the case of the bicycle wheel hub assembly according to the thirty-second aspect, it is possible to further improve the design freedom of the internal structure of the bicycle wheel hub assembly. For example, a transmission structure such as a one-way coupling structure may be accommodated within the internal cavity of this larger diameter portion of the sprocket support body. According to a thirty-third aspect of the present invention, a bicycle wheel hub assembly includes a sprocket support body. The sprocket support body includes at least nine external spline teeth structured to engage a bicycle rear sprocket assembly. At least one of the at least nine external spline teeth has an asymmetric shape relative to a circumferential tooth tip centerline. The at least one of the at least nine external spline teeth includes an external spline drive surface and an external spline non-drive surface. The external spline drive surface has a first external spline surface angle defined between the external spline drive surface and a first radial line extending from a center of rotation of the bicycle hub assembly The axis extends to one of the radially outermost edges of the external splined drive surface. The external splined non-drive surface has a second external spline surface angle defined between the external splined non-drive surface and a second radial line extending from the bicycle wheel hub assembly. The center axis of rotation extends to the radially outermost edge of one of the external splined non-drive surfaces. The second outer spline surface angle is different from the first outer spline surface angle. In the case of the bicycle hub assembly according to the thirty-third aspect, it is possible to reduce the weight of the sprocket support body while ensuring the strength of the external spline teeth of the sprocket support body. According to a thirty-fourth aspect of the present invention, the bicycle wheel hub assembly of the thirty-third aspect is structurally designed such that the first external spline surface angle is smaller than the second external spline surface angle. In the case of the bicycle hub assembly according to the thirty-fourth aspect, it is possible to effectively reduce the weight of the sprocket support body while ensuring the strength of the external spline teeth of the sprocket support body. According to a thirty-fifth aspect of the present invention, the bicycle wheel hub assembly of the thirty-third aspect or the thirty-fourth aspect is structurally designed such that the first external spline surface angle is between 0 degrees and 10 degrees. within the range. In the case of the bicycle wheel hub assembly according to the thirty-fifth aspect, the first external spline surface angle ensures the strength of the external spline transmission surface. According to a thirty-sixth aspect of the present invention, the bicycle wheel hub assembly of any one of the thirty-third to thirty-fifth aspects is structurally designed such that the second external spline surface angle is at 0 degrees to within the range of 60 degrees. In the case of the bicycle hub assembly according to the thirty-sixth aspect, the second external spline surface angle reduces the weight of the external spline teeth of the sprocket support body. According to a thirty-seventh aspect of the present invention, the bicycle wheel hub assembly of any one of the thirty-third to thirty-sixth aspects is structurally designed such that the at least ten external spline teeth have a first an outer pitch angle and a second outer pitch angle different from the first outer pitch angle. In the case of the bicycle wheel hub assembly according to the thirty-seventh aspect, the difference between the first outer pitch angle and the second outer pitch angle helps the user to correctly install the bicycle rear sprocket assembly to the sprocket. The supporting body, especially the circumferential position of each sprocket of the bicycle rear sprocket assembly.

Embodiments will now be described with reference to the accompanying drawings, wherein like reference numerals designate corresponding or identical elements throughout the various views. Referring first to FIG. 1 , a bicycle transmission system 10 according to an embodiment includes a bicycle hub assembly 12 and a bicycle rear sprocket assembly 14 . The bicycle hub assembly 12 is fastened to the bicycle frame BF. The bicycle rear sprocket assembly 14 is installed on the bicycle wheel hub assembly 12 . The bicycle brake rotor 16 is installed on the bicycle wheel hub assembly 12 . The bicycle transmission system 10 further includes a crank assembly 18 and a bicycle chain 20 . The crank assembly 18 includes a crankshaft 22 , a right crank arm 24 , a left crank arm 26 and a front sprocket 27 . Right crank arm 24 and left crank arm 26 are secured to crankshaft 22 . The front sprocket 27 is secured to at least one of the crankshaft 22 and the right crank arm 24 . The bicycle chain 20 is engaged with the front sprocket 27 and the bicycle rear sprocket assembly 14 to transmit the pedaling force from the front sprocket 27 to the bicycle rear sprocket assembly 14 . Crank assembly 18 includes front sprocket 27 as a single sprocket in the illustrated embodiment. However, the crank assembly 18 may include a plurality of front sprockets. Bicycle rear sprocket assembly 14 is a rear sprocket assembly. However, the structure of the bicycle rear sprocket assembly 14 can be applied to the front sprocket. In this application, the following directional terms "front", "back", "forward", "backward", "left", "right", "lateral", "upward" and "downward" and any other Similar directional terms refer to directions based on a user (eg, a rider) sitting on the saddle (not shown) of a bicycle and facing the handlebars (not shown). Accordingly, these terms, when used to describe a bicycle drivetrain 10, a bicycle hub assembly 12, or a bicycle rear sprocket assembly 14, shall refer to a bicycle drivetrain 10 equipped as if used in an upright riding position on a horizontal surface. , a bicycle hub assembly 12 or a bicycle rear sprocket assembly 14. As seen in FIGS. 2 and 3 , the bicycle hub assembly 12 and the bicycle rear sprocket assembly 14 have a rotation center axis A1 . The bicycle rear sprocket assembly 14 is rotatably supported by the bicycle hub assembly 12 about the rotation center axis A1 relative to the bicycle frame BF (Fig. 1). The bicycle rear sprocket assembly 14 is structurally designed to engage the bicycle chain 20 to transmit transmission rotational force F1 between the bicycle chain 20 and the bicycle rear sprocket assembly 14 during pedaling. During pedaling, the bicycle rear sprocket assembly 14 rotates around the rotation center axis A1 in the transmission rotation direction D11. The transmission rotation direction D11 is defined along the circumferential direction D1 of the bicycle hub assembly 12 or the bicycle rear sprocket assembly 14 . The reverse rotation direction D12 is the opposite direction of the transmission rotation direction D11 and is defined along the circumferential direction D1. As seen in FIG. 2 , the bicycle hub assembly 12 includes a sprocket support body 28 . The bicycle rear sprocket assembly 14 is installed on the sprocket support body 28 to transmit the transmission rotation force F1 between the sprocket support body 28 and the bicycle rear sprocket assembly 14 . The bicycle hub assembly 12 further includes a hub axle 30 . The sprocket support body 28 is rotatably mounted on the hub shaft 30 around the rotation center axis A1. The bicycle hub assembly 12 includes a locking ring 32 . The locking ring 32 is fastened to the sprocket support body 28 to retain the bicycle rear sprocket assembly 14 relative to the sprocket support body 28 in an axial direction D2 parallel to the central axis of rotation A1. As seen in Figure 4, the bicycle hub assembly 12 is fastened to the bicycle frame BF by the wheel fastening structure WS. The hub shaft 30 has a through hole 30A. The fastening rod WS1 of the wheel fastening structure WS extends through the through hole 30A of the hub shaft 30 . The hub shaft 30 includes a first shaft end 30B and a second shaft end 30C. The hub shaft 30 extends along the rotation center axis A1 between the first shaft end 30B and the second shaft end 30C. The first shaft end 30B is disposed in the first groove BF11 of the first frame BF1 of the bicycle frame BF. The second shaft end 30C is disposed in the second groove BF21 of the second frame BF2 of the bicycle frame BF. The hub shaft 30 is held between the first frame BF1 and the second frame BF2 by the wheel fastening structure WS. The wheel fastening structures WS include structures known from the claimed bicycle. Therefore, for the sake of brevity, it will not be described in detail here. As seen in FIGS. 4 and 5 , the bicycle hub assembly 12 further includes a brake rotor support body 34 . The brake rotor support body 34 is rotatably mounted on the hub shaft 30 about the rotation center axis A1. The brake rotor support body 34 is coupled to the bicycle brake rotor 16 ( FIG. 1 ) to transmit braking rotational force from the bicycle brake rotor 16 to the brake rotor support body 34 . As seen in FIG. 5 , the bicycle hub assembly 12 further includes a hub body 36 . The hub body 36 is rotatably mounted on the hub shaft 30 around the rotation center axis A1. In this embodiment, the sprocket support body 28 is a separate component from the hub body 36 . The brake rotor support body 34 is integrally provided with the hub body 36 as a one-piece unitary member. However, the sprocket support body 28 may be provided integrally with the hub body 36 . Brake rotor support body 34 may be a separate component from hub body 36 . The hub body 36 includes a first flange 36A and a second flange 36B. A first spoke (not shown) is coupled to first flange 36A. A second spoke (not shown) is coupled to second flange 36B. The second flange 36B is spaced apart from the first flange 36A in the axial direction D2. The first flange 36A is provided between the sprocket support body 28 and the second flange 36B in the axial direction D2. The second flange 36B is provided between the first flange 36A and the brake rotor support body 34 in the axial direction D2. Locking ring 32 includes an outer threaded portion 32A. The sprocket support body 28 includes an interior threaded portion 28A. In the state where the lock ring 32 is fastened to the sprocket support body 28, the outer threaded portion 32A threadably engages the inner threaded portion 28A. As seen in FIG. 6 , the bicycle hub assembly 12 further includes a ratchet structure 38 . The sprocket support body 28 is operably coupled to the hub body 36 by a ratchet structure 38 . The ratchet structure 38 is structurally designed to couple the sprocket support body 28 to the hub body 36, thereby causing the sprocket support body 28 together with the hub body 36 to rotate in the transmission rotation direction D11 (Fig. 5) during pedaling. The ratchet structure 38 is structurally designed to allow the sprocket support body 28 to rotate relative to the hub body 36 in the counter-rotational direction D12 (Fig. 5) during idle. Therefore, the ratchet structure 38 can be interpreted as a one-way coupling structure 38 . The ratchet structure 38 includes structures known in the bicycle art. Therefore, for the sake of brevity, it will not be described in detail here. The bicycle hub assembly 12 includes a first bearing 39A and a second bearing 39B. The first bearing 39A and the second bearing 39B are provided between the sprocket support body 28 and the hub shaft 30 to rotatably support the sprocket support body 28 around the rotation center axis A1 relative to the hub shaft 30 . In this embodiment, each of the sprocket support body 28, the brake rotor support body 34, and the hub body 36 are made of a metallic material such as aluminum, iron, or titanium. However, at least one of sprocket support body 28, brake rotor support body 34, and hub body 36 may be made from non-metallic materials. As seen in Figures 7 and 8, the sprocket support body 28 includes at least one external spline tooth 40 structured to engage the bicycle rear sprocket assembly 14 (Fig. 6). The sprocket support body 28 includes a plurality of external spline teeth 40 structured to engage the bicycle rear sprocket assembly 14 (FIG. 6). That is, at least one external spline tooth 40 includes a plurality of external spline teeth 40 . The sprocket support body 28 includes at least nine external spline teeth 40 structured to engage the bicycle rear sprocket assembly 14 (FIG. 6). The sprocket support body 28 includes at least ten external spline teeth 40 structured to engage the bicycle rear sprocket assembly 14 (FIG. 6). The sprocket support body 28 includes a base support 41 having a tubular shape. The base support 41 extends along the rotation center axis A1 and has a single diameter portion (as shown in FIG. 7 ). External spline teeth 40 extend radially outward from the base support 41 . The sprocket support body 28 includes a larger diameter portion 42 , a flange 44 and a plurality of helical external spline teeth 46 . The larger diameter portion 42 and flange 44 extend radially outward from the base support 41 . The larger diameter portion 42 is disposed in the axial direction D2 between the plurality of external spline teeth 40 and the flange 44 . The larger diameter portion 42 and the flange 44 are disposed in the axial direction D2 between the plurality of external spline teeth 40 and the plurality of helical external spline teeth 46 . As seen in FIG. 6 , the bicycle rear sprocket assembly 14 is held in the axial direction D2 between the larger diameter portion 42 and the locking flange 32B of the locking ring 32 . The larger diameter portion 42 may have an internal cavity such that a transmission structure such as a one-way coupling structure may be accommodated within the internal cavity. The larger diameter portion 42 may be omitted from the bicycle hub assembly 12 if desired. As seen in Figure 9, the total number of at least ten external spline teeth 40 is equal to or greater than 20. The total number of at least ten external spline teeth 40 is equal to or greater than 25. In this embodiment, the total number of at least ten external spline teeth 40 is twenty-six. However, the total number of external spline teeth 40 is not limited to this embodiment and the above range. At least ten external spline teeth 40 have a first external peripheral pitch angle PA11 and a second external peripheral pitch angle PA12. At least two of the plurality of external spline teeth 40 are circumferentially arranged at a first external pitch angle PA11 with respect to the rotation center axis A1 of the bicycle hub assembly 12 . At least two of the plurality of external spline teeth 40 are circumferentially arranged at a second external pitch angle PA12 with respect to the rotation center axis A1 of the bicycle hub assembly 12 . In this embodiment, the second outer pitch angle PA12 is different from the first outer pitch angle PA11. However, the second outer pitch angle PA12 may be substantially equal to the first outer pitch angle PA11. In this embodiment, the external spline teeth 40 are arranged at a first external pitch angle PA11 in the circumferential direction D1. Two of the external spline teeth 40 are arranged at a second external pitch angle PA12 in the circumferential direction D1. However, at least two of the external spline teeth 40 may be arranged at another external pitch angle in the circumferential direction D1. The first outer peripheral pitch angle PA11 is in the range of 10 degrees to 20 degrees. The first outer peripheral pitch angle PA11 is in the range of 12 degrees to 15 degrees. The first outer peripheral pitch angle PA11 is in the range of 13 degrees to 14 degrees. In this embodiment, the first outer peripheral pitch angle PA11 is 13.3 degrees. However, the first outer peripheral pitch angle PA11 is not limited to this embodiment and the above range. The second peripheral pitch angle PA12 is in the range of 5 degrees to 30 degrees. In this embodiment, the second outer peripheral pitch angle PA12 is 26 degrees. However, the second outer peripheral pitch angle PA12 is not limited to this embodiment and the above range. The outer spline teeth 40 have substantially the same shape as each other. The outer spline teeth 40 have substantially the same spline size as each other. The outer spline teeth 40 have substantially the same profile as each other when viewed along the rotational center axis A1. However, as seen in FIG. 10 , at least one of the at least ten external spline teeth 40 may have a first spline shape that is different from a second spline shape of another of the at least ten external spline teeth 40 . . At least one of the at least ten external spline teeth 40 may have a first spline size that is different from a second spline size of another of the at least ten external spline teeth 40 . When viewed along the rotational center axis A1 , at least one of the at least ten external spline teeth 40 may have a profile that is different from the profile of another of the at least ten external spline teeth 40 . In FIG. 10 , one of the outer spline teeth 40 has a spline shape that is different from the spline shape of the other teeth of the outer spline teeth 40 . One of the external spline teeth 40 has a spline size that is different from the spline size of the other teeth of the external spline teeth 40 . When viewed along the rotational center axis A1 , one of the outer spline teeth 40 has a profile that is different from the profile of the other teeth of the outer spline teeth 40 . As seen in FIG. 11 , each of the at least ten external spline teeth 40 has an external spline drive surface 48 and an external spline non-drive surface 50 . The plurality of external spline teeth 40 includes a plurality of external spline transmission surfaces 48 for receiving transmission rotational force F1 from the bicycle rear sprocket assembly 14 (FIG. 6) during pedaling. The plurality of external spline teeth 40 includes a plurality of external spline non-drive surfaces 50 . The external splined transmission surface 48 may contact the bicycle rear sprocket assembly 14 to receive transmission rotational force F1 from the bicycle rear sprocket assembly 14 (FIG. 6) during pedaling. The outer splined drive surface 48 faces the counter-rotational direction D12. The external splined non-drive surface 50 is provided on the opposite side of the external splined drive surface 48 in the circumferential direction D1. The outer splined non-drive surface 50 faces the drive rotation direction D11 so as not to receive the drive rotation force F1 from the bicycle rear sprocket assembly 14 during pedaling. At least ten external spline teeth 40 each have a maximum circumferential width MW1. The external spline teeth 40 each have a maximum circumferential width MW1. The maximum circumferential width MW1 is defined as the maximum width that receives the thrust force F2 applied to the outer spline teeth 40 . The maximum circumferential width MW1 is defined as the straight-line distance from the outer splined drive surface 48 . The plurality of outer splined drive surfaces 48 each include a radially outermost edge 48A and a radially innermost edge 48B. The outer splined drive surface 48 extends from the radially outermost edge 48A to the radially innermost edge 48B. The first reference circle RC11 is defined on the radially innermost edge 48B and is centered on the rotation center axis A1. The first reference circle RC11 intersects the external splined non-drive surface 50 at the reference point 50R. The maximum circumferential width MW1 extends straight from the radially innermost edge 48B to the reference point 50R in the circumferential direction D1. The plurality of external splined non-drive surfaces 50 each include a radially outermost edge 50A and a radially innermost edge 50B. The outer splined non-drive surface 50 extends from the radially outermost edge 50A to the radially innermost edge 50B. The reference point 50R is provided between the radially outermost edge 50A and the radially innermost edge 50B. However, the reference point 50R may coincide with the radially innermost edge 50B. The sum of the maximum circumferential widths MW1 is equal to or greater than 55 mm. The sum of the maximum circumferential widths MW1 is equal to or greater than 60 mm. The sum of the maximum circumferential widths MW1 is equal to or greater than 65 mm. In this embodiment, the sum of the maximum circumferential widths MW1 is 68 mm. However, the sum of the maximum circumferential widths MW1 is not limited to this embodiment and the above range. As seen in Figure 12, at least one external spline tooth 40 has an external spline tip diameter DM11. The external spline top diameter DM11 is equal to or greater than 25 mm. The external spline top diameter DM11 is equal to or greater than 29 mm. The external spline top diameter DM11 is equal to or less than 30 mm. In this example, the external spline tip diameter DM11 is 29.6 mm. However, the external spline top diameter DM11 is not limited to this embodiment and the above range. At least one external spline tooth 40 has an external spline base diameter DM12. At least one external spline tooth 40 has an external spline root circle RC12 having an external spline base diameter DM12. However, the external spline root circle RC12 may have another diameter than the external spline base diameter DM12. External spline base diameter DM12 is equal to or less than 28 mm. The base diameter of the external spline DM12 is equal to or greater than 25 mm. The base diameter of the external spline DM12 is equal to or greater than 27 mm. In this example, the external spline base diameter DM12 is 27.2 mm. However, the outer spline bottom diameter DM12 is not limited to this embodiment and the above range. The larger diameter portion 42 has an outer diameter DM13 that is larger than the outer spline top diameter DM11. The outer diameter DM13 is in the range of 32 mm to 40 mm. In this example, the outer diameter DM13 is 35 mm. However, the outer diameter DM13 is not limited to this embodiment. As seen in FIG. 11 , the plurality of outer splined drive surfaces 48 each include a radial length RL11 bounded from a radially outermost edge 48A to a radially innermost edge 48B. The sum of the radial lengths RL11 of the plurality of external spline transmission surfaces 48 is equal to or greater than 7 mm. The sum of the radial lengths RL11 is equal to or greater than 10 mm. The sum of the radial lengths RL11 is equal to or greater than 15 mm. In this embodiment, the sum of the radial lengths RL11 is 19.5 mm. However, the sum of the radial lengths RL11 is not limited to this embodiment. The plurality of external spline teeth 40 have an additional radial length RL12. The additional radial length RL12 is respectively defined from the outer spline tooth root circle RC12 to the radially outermost ends 40A of the plurality of outer spline teeth 40 . The sum of the additional radial lengths RL12 is equal to or greater than 12 mm. In this embodiment, the sum of the additional radial lengths RL12 is 31.85 mm. However, the sum of the additional radial lengths RL12 is not limited to this embodiment. At least one of the at least nine external spline teeth 40 has an asymmetric shape relative to the circumferential tooth tip centerline CL1. The circumferential tooth tip center line CL1 is a line connecting the rotation center axis A1 and the circumferential center point CP1 of the radially outermost end 40A of the external spline teeth 40 . However, at least one of the outer spline teeth 40 may have a symmetrical shape relative to the circumferential tooth tip centerline CL1. At least one of the at least nine external spline teeth 40 includes an external spline drive surface 48 and an external spline non-drive surface 50 . External spline drive surface 48 has a first external spline surface angle AG11. A first outer spline surface angle AG11 is defined between the outer spline drive surface 48 and the first radial line L11. The first radial line L11 extends from the rotational center axis A1 of the bicycle hub assembly 12 to the radially outermost edge 48A of the outer spline transmission surface 48 . The first outer pitch angle PA11 or the second outer pitch angle PA12 is defined between adjacent first radial lines L11 (see, for example, FIG. 9 ). The outer splined non-drive surface 50 has a second outer spline surface angle AG12. A second outer spline surface angle AG12 is defined between the outer spline non-drive surface 50 and the second radial line L12. The second radial line L12 extends from the rotational center axis A1 of the bicycle hub assembly 12 to the radially outermost edge 50A of the outer splined non-drive surface 50 . In this embodiment, the second outer spline surface angle AG12 is different from the first outer spline surface angle AG11. The first outer spline surface angle AG11 is smaller than the second outer spline surface angle AG12. However, the first outer spline surface angle AG11 may be equal to or greater than the second outer spline surface angle AG12. The first external spline surface angle AG11 is in the range of 0 degrees to 10 degrees. The second external spline surface angle AG12 is in the range of 0 degrees to 60 degrees. In this embodiment, the first outer spline surface angle AG11 is 5 degrees. The second external spline surface angle AG12 is 45 degrees. However, the first external spline surface angle AG11 and the second external spline surface angle AG12 are not limited to this embodiment and the above range. As seen in Figures 13 and 14, the brake rotor support body 34 includes at least one additional external spline tooth 52 structured to engage the bicycle brake rotor 16 (Figure 4). In this embodiment, the brake rotor support body 34 includes an additional base support 54 and a plurality of additional external spline teeth 52 . The additional base support 54 has a tubular shape and extends from the hub body 36 along the central axis of rotation A1. Additional external spline teeth 52 extend radially outwardly from the additional base support 54 . The total number of additional external spline teeth 52 is 52. However, the total number of additional external spline teeth 52 is not limited to this embodiment. As seen in Figure 14, at least one additional external spline tooth 52 has an additional external spline tip diameter DM14. As seen in Figure 15, the additional outer spline crown diameter DM14 is larger than the outer spline crown diameter DM11. The additional outer spline tip diameter DM14 is substantially equal to the larger diameter portion 42 outer diameter DM13. However, the additional outer spline crown diameter DM14 may be equal to or smaller than the outer spline crown diameter DM11. The additional outer spline tip diameter DM14 may be different than the larger diameter portion 42 outer diameter DM13. As seen in Figure 16, the hub axle 30 includes an axial contact surface 30B1 for contacting the bicycle frame BF. In this embodiment, the axial contact surface 30B1 may be in contact with the first frame BF1 of the bicycle frame BF. The first frame BF1 includes a frame contact surface BF12. In a state where the bicycle hub assembly 12 is fastened to the bicycle frame BF by the wheel fastening structure WS, the axial contact surface 30B1 is in contact with the frame contact surface BF12. The first axial length AL11 is defined in the axial direction D2 relative to the rotational center axis A1 from the axial contact surface 30B1 to the larger diameter portion 42 . The first axial length AL11 is in the range of 35 mm to 41 mm. The first axial length AL11 may be equal to or greater than 39 mm. The first axial length AL11 can also be in the range of 35 mm to 37 mm. In this embodiment, the first axial length AL11 is 36.2 mm. However, the first axial length AL11 is not limited to this embodiment and the above range. The larger diameter portion 42 has an axial end 42A furthest from the axial contact surface 30B1 in the axial direction D2. The second axial length AL12 is defined in the axial direction D2 from the axial contact surface 30B1 to the axial end 42A. The second axial length AL12 is in the range of 38 mm to 47 mm. The second axial length AL12 may be in the range of 44 mm to 45 mm. The second axial length AL12 can also be in the range of 40 mm to 41 mm. In this embodiment, the second axial length AL12 is 40.75 mm. However, the second axial length AL12 is not limited to this embodiment and the above range. The axial length AL13 of the larger diameter portion 42 is in the range of 3 mm to 6 mm. In this example, the axial length AL13 is 4.55 mm. However, the axial length AL13 is not limited to this embodiment and the above range. As seen in Figure 17, the bicycle rear sprocket assembly 14 includes at least one sprocket. At least one sprocket includes the smallest sprocket SP1 and the largest sprocket SP12. The smallest sprocket SP1 may also be called sprocket SP1. The largest sprocket SP12 may also be called sprocket SP12. In this embodiment, the at least one sprocket further includes sprockets SP2 to SP11. Sprocket SP1 corresponds to the high-speed gear. Sprocket SP12 corresponds to the low speed gear. The total number of sprockets of the bicycle rear sprocket assembly 14 is not limited to this embodiment. The smallest sprocket SP1 includes at least one sprocket tooth SP1B. The total number of at least one sprocket tooth SP1B of the smallest sprocket SP1 is equal to or less than 10. In this embodiment, the total number of at least one sprocket tooth SP1B of the smallest sprocket SP1 is ten. However, the total number of at least one sprocket tooth SP1B of the smallest sprocket SP1 is not limited to this embodiment and the above range. The largest sprocket SP12 includes at least one sprocket tooth SP12B. The total number of at least one sprocket tooth SP12B of the largest sprocket SP12 is equal to or greater than 46. The total number of at least one sprocket tooth SP12B of the largest sprocket SP12 is equal to or greater than 50. In this embodiment, the total number of at least one sprocket tooth SP12B of the largest sprocket SP12 is 51. However, the total number of at least one sprocket tooth SP12B of the largest sprocket SP12 is not limited to this embodiment and the above scope. Sprocket SP2 includes at least one sprocket tooth SP2B. Sprocket SP3 includes at least one sprocket tooth SP3B. Sprocket SP4 includes at least one sprocket tooth SP4B. Sprocket SP5 includes at least one sprocket tooth SP5B. Sprocket SP6 includes at least one sprocket tooth SP6B. Sprocket SP7 includes at least one sprocket tooth SP7B. Sprocket SP8 includes at least one sprocket tooth SP8B. Sprocket SP9 includes at least one sprocket tooth SP9B. Sprocket SP10 includes at least one sprocket tooth SP10B. Sprocket SP11 includes at least one sprocket tooth SP11B. The total number of at least one sprocket tooth SP2B is twelve. The total number of at least one sprocket tooth SP3B is 14. The total number of at least one sprocket tooth SP4B is 16. The total number of at least one sprocket tooth SP5B is 18. The total number of at least one sprocket tooth SP6B is 21. The total number of at least one sprocket tooth SP7B is 24. The total number of at least one sprocket tooth SP8B is 28. The total number of at least one sprocket tooth SP9B is 33. The total number of at least one sprocket tooth SP10B is 39. The total number of at least one sprocket tooth SP11B is 45. The total number of sprocket teeth of each of the sprockets SP2 to SP11 is not limited to this embodiment. As seen in Fig. 18, the sprockets SP1 to SP12 are separate members from each other. However, at least one of the sprockets SP1 to SP12 may be provided at least partially integrally with the other of the sprockets SP1 to SP12. The bicycle rear sprocket assembly 14 includes a sprocket support 56, a plurality of spacers 58, a first ring 59A and a second ring 59B. In the illustrated embodiment, sprockets SP1 - SP12 are attached to sprocket support 56 . As seen in FIG. 19 , the sprocket SP1 includes a sprocket body SP1A and a plurality of sprocket teeth SP1B. A plurality of sprocket teeth SP1B extend radially outward from the sprocket body SP1A. Sprocket SP2 includes a sprocket body SP2A and a plurality of sprocket teeth SP2B. A plurality of sprocket teeth SP2B extend radially outward from the sprocket body SP2A. The sprocket SP3 includes a sprocket body SP3A and a plurality of sprocket teeth SP3B. A plurality of sprocket teeth SP3B extend radially outward from the sprocket body SP3A. The sprocket SP4 includes a sprocket body SP4A and a plurality of sprocket teeth SP4B. A plurality of sprocket teeth SP4B extend radially outward from the sprocket body SP4A. The sprocket SP5 includes a sprocket body SP5A and a plurality of sprocket teeth SP5B. A plurality of sprocket teeth SP5B extend radially outward from the sprocket body SP5A. The first ring 59A is provided between sprockets SP3 and SP4. The second ring 59B is provided between sprockets SP4 and SP5. As seen in FIG. 20 , the sprocket SP6 includes a sprocket body SP6A and a plurality of sprocket teeth SP6B. A plurality of sprocket teeth SP6B extend radially outward from the sprocket body SP6A. The sprocket SP7 includes a sprocket body SP7A and a plurality of sprocket teeth SP7B. A plurality of sprocket teeth SP7B extend radially outward from the sprocket body SP7A. The sprocket SP8 includes a sprocket body SP8A and a plurality of sprocket teeth SP8B. A plurality of sprocket teeth SP8B extend radially outward from the sprocket body SP8A. As seen in FIG. 21 , the sprocket SP9 includes a sprocket body SP9A and a plurality of sprocket teeth SP9B. A plurality of sprocket teeth SP9B extend radially outward from the sprocket body SP9A. Sprocket SP10 includes a sprocket body SP10A and a plurality of sprocket teeth SP10B. A plurality of sprocket teeth SP10B extend radially outward from the sprocket body SP10A. Sprocket SP11 includes a sprocket body SP11A and a plurality of sprocket teeth SP11B. A plurality of sprocket teeth SP11B extend radially outward from the sprocket body SP11A. Sprocket SP12 includes a sprocket body SP12A and a plurality of sprocket teeth SP12B. A plurality of sprocket teeth SP12B extend radially outward from the sprocket body SP12A. As seen in FIG. 22 , the sprocket support 56 includes a hub engaging portion 60 and a plurality of support arms 62 . A plurality of support arms 62 extend radially outward from the hub engaging portion 60 . The support arm 62 includes first to eighth attachment portions 62A to 62H. The plurality of spacers 58 include a plurality of first spacers 58A, a plurality of second spacers 58B, a plurality of third spacers 58C, a plurality of fourth spacers 58D, a plurality of fifth spacers 58E, a plurality of sixth spacers 58E, and a plurality of sixth spacers 58C. Spacer 58F and a plurality of seventh spacers 58G. As seen in Fig. 23, the first spacer 58A is provided between sprockets SP5 and SP6. The second spacer 58B is provided between sprocket SP6 and sprocket SP7. The third spacer 58C is provided between the sprocket SP7 and the sprocket SP8. The fourth spacer 58D is provided between sprockets SP8 and SP9. The fifth spacer 58E is provided between the sprocket SP9 and the sprocket SP10. The sixth spacer 58F is provided between the sprocket SP10 and the sprocket SP11. The seventh spacer 58G is provided between the sprocket SP11 and the sprocket SP12. Sprocket SP6 and first spacer 58A are attached to first attachment portion 62A by an adhesive structure such as adhesive. The sprocket SP7 and the second spacer 58B are attached to the second attachment portion 62B by an adhesive structure such as adhesive. Sprocket SP8 and third spacer 58C are attached to third attachment portion 62C by an adhesive structure such as adhesive. The sprocket SP9 and the fourth spacer 58D are attached to the fourth attachment portion 62D by an adhesive structure such as adhesive. The sprocket SP10 and the fifth spacer 58E are attached to the fifth attachment portion 62E by an adhesive structure such as adhesive. The sprocket SP11 and the sixth spacer 58F are attached to the sixth attachment portion 62F by an adhesive structure such as adhesive. The sprocket SP12 and the seventh spacer 58G are attached to the seventh attachment portion 62G by an adhesive structure such as adhesive. Sprocket SP5 and second ring 59B are attached to eighth attachment portion 62H by an adhesive structure such as adhesive. The hub engaging portion 60 , the sprockets SP1 to SP4 , the first ring 59A and the second ring 59B are held in the axial direction D2 between the larger diameter portion 42 and the locking flange 32B of the locking ring 32 . In this embodiment, each of the sprockets SP1 to SP12 is made of a metal material such as aluminum, iron, or titanium. Each of the sprocket support 56 , the first to seventh spacers 58A to 58G, the first ring 59A and the second ring 59B is made of a non-metal material such as a resin material. However, at least one of the sprockets SP1 to SP12 may be at least partially made of non-metallic material. At least one of the sprocket support 56 , the first to seventh spacers 58A to 58G, the first ring 59A and the second ring 59B may be at least partially made of a metal material such as aluminum, iron, or titanium. At least one sprocket includes at least one internal spline tooth structured to engage the bicycle hub assembly 12 . As seen in FIGS. 24 and 25 , at least one sprocket includes at least ten internal spline teeth structured to engage the bicycle hub assembly 12 . At least one internal spline tooth includes a plurality of internal spline teeth. Accordingly, at least one sprocket includes a plurality of internal spline teeth structured to engage the bicycle hub assembly 12 . In this embodiment, sprocket SP1 includes at least ten internal spline teeth 64 structured to engage the bicycle hub assembly 12 . In this embodiment, sprocket SP1 includes internal spline teeth 64 configured to engage external spline teeth 40 of sprocket support body 28 of bicycle hub assembly 12 . The sprocket body SP1A has an annular shape. Internal spline teeth 64 extend radially inwardly from sprocket body SP1A. As seen in Figure 26, the total number of at least ten internal spline teeth 64 is equal to or greater than twenty. The total number of at least ten internal spline teeth 64 is equal to or greater than 25. In this embodiment, the total number of internal spline teeth 64 is twenty-six. However, the total number of internal spline teeth 64 is not limited to this embodiment and the above scope. At least ten internal spline teeth 64 have a first internal pitch angle PA21 and a second internal pitch angle PA22. At least two of the plurality of internal spline teeth 64 are circumferentially arranged at a first internal pitch angle PA21 with respect to the rotation center axis A1 of the bicycle rear sprocket assembly 14 . At least two of the plurality of internal spline teeth 64 are circumferentially arranged at a second internal pitch angle PA22 with respect to the rotation center axis A1. In this embodiment, the second inner pitch angle PA22 is different from the first inner pitch angle PA21. However, the second inner pitch angle PA22 may be substantially equal to the first inner pitch angle PA21. In this embodiment, the internal spline teeth 64 are circumferentially arranged at a first internal pitch angle PA21 in the circumferential direction D1. Two of the internal spline teeth 64 are arranged at a second internal pitch angle PA22 in the circumferential direction D1. However, at least two of the internal spline teeth 64 may be arranged at another internal pitch angle in the circumferential direction D1. The first internal pitch angle PA21 is in the range of 10 degrees to 20 degrees. The first internal pitch angle PA21 is in the range of 12 degrees to 15 degrees. The first internal pitch angle PA21 is in the range of 13 degrees to 14 degrees. In this embodiment, the first internal pitch angle PA21 is 13.3 degrees. However, the first internal pitch angle PA21 is not limited to this embodiment and the above range. The second internal pitch angle PA22 is in the range of 5 degrees to 30 degrees. In this embodiment, the second internal pitch angle PA22 is 26 degrees. However, the second internal pitch angle PA22 is not limited to this embodiment and the above range. At least one of the at least ten internal spline teeth 64 has a first spline shape that is different from a second spline shape of another of the at least ten internal spline teeth 64 . At least one of the at least ten internal spline teeth 64 has a first spline size that is different from a second spline size of another of the at least ten internal spline teeth 64 . At least one of the at least ten internal spline teeth 64 has a cross-sectional shape that is different from the cross-sectional shape of another of the at least ten internal spline teeth 64 . However, as seen in Figure 27, the internal spline teeth 64 may have the same shape as each other. The internal spline teeth 64 may be the same size as each other. The internal spline teeth 64 may have the same cross-sectional shape as each other. As seen in Figure 28, at least one internal spline tooth 64 includes an internal spline drive surface 66 and an internal spline non-drive surface 68. At least one internal spline tooth 64 includes a plurality of internal spline teeth 64 . The plurality of internal spline teeth 64 includes a plurality of internal spline transmission surfaces 66 for receiving transmission rotational force F1 from the bicycle hub assembly 12 (FIG. 6) during pedaling. The plurality of internal spline teeth 64 includes a plurality of internal spline non-drive surfaces 68 . Internal splined transmission surface 66 may contact sprocket support body 28 to transmit transmission rotational force F1 from sprocket SP1 to sprocket support body 28 during pedaling. The internal splined drive surface 66 faces the drive rotation direction D11. The internal splined non-drive surface 68 is provided on the opposite side of the internal splined drive surface 66 in the circumferential direction D1. The internal splined non-drive surface 68 faces the counter-rotational direction D12 so that no drive rotational force F1 is transmitted from the sprocket SP1 to the sprocket support body 28 during pedaling. At least ten internal spline teeth 64 each have a maximum circumferential width MW2. The internal spline teeth 64 each have a maximum circumferential width MW2. The circumferential maximum width MW2 is defined as the maximum width that receives the thrust F3 applied to the inner spline teeth 64 . Maximum circumferential width MW2 is defined as the linear distance based on the internal splined transmission surface 66. Internal splined drive surface 66 includes a radially outermost edge 66A and a radially innermost edge 66B. Internal splined drive surface 66 extends from radially outermost edge 66A to radially innermost edge 66B. The second reference circle RC21 is defined on the radially outermost edge 66A and is centered on the rotation center axis A1. The second reference circle RC21 intersects the internal splined non-drive surface 68 at the reference point 68R. The maximum circumferential width MW2 extends straight from the radially innermost edge 66B to the reference point 68R in the circumferential direction D1. The internal splined non-drive surface 68 includes a radially outermost edge 68A and a radially innermost edge 68B. The internal splined non-drive surface 68 extends from the radially outermost edge 68A to the radially innermost edge 68B. Reference point 68R is provided between radially outermost edge 68A and radially innermost edge 68B. The sum of the maximum circumferential widths MW2 is equal to or greater than 40 mm. The sum of the maximum circumferential widths MW2 is equal to or greater than 45 mm. The sum of the maximum circumferential widths MW2 is equal to or greater than 50 mm. In this embodiment, the sum of the maximum circumferential widths MW2 is 50.8 mm. However, the sum of the circumferential maximum widths MW2 is not limited to this embodiment. As seen in Figure 29, at least one internal spline tooth 64 has an internal spline tip diameter DM21. At least one internal spline tooth 64 has an internal spline root circle RC22 having an internal spline crown diameter DM21. However, the internal spline root circle RC22 may have another diameter than the internal spline top diameter DM21. Internal spline top diameter DM21 is equal to or less than 30 mm. The internal spline top diameter DM21 is equal to or greater than 25 mm. Internal spline top diameter DM21 is equal to or greater than 29 mm. In this example, the internal spline tip diameter DM21 is 29.8 mm. However, the inner spline top diameter DM21 is not limited to this embodiment and the above range. At least one internal spline tooth 64 has an internal spline base diameter DM22 equal to or less than 28 mm. Internal spline bottom diameter DM22 is equal to or greater than 25 mm. Internal spline bottom diameter DM22 is equal to or greater than 27 mm. In this example, the internal spline base diameter DM22 is 27.7 mm. However, the inner spline bottom diameter DM22 is not limited to this embodiment and the above range. As seen in Figure 28, the plurality of internal splined transmission surfaces 66 includes a radially outermost edge 66A and a radially innermost edge 66B. The plurality of internal spline transmission surfaces 66 each include a radial length RL21 bounded from a radially outermost edge 66A to a radially innermost edge 66B. The sum of the radial lengths RL21 of the plurality of internal spline transmission surfaces 66 is equal to or greater than 7 mm. The sum of the radial lengths RL21 is equal to or greater than 10 mm. The sum of the radial lengths RL21 is equal to or greater than 15 mm. In this embodiment, the sum of the radial lengths RL21 is 19.5 mm. However, the total radial length RL21 is not limited to this embodiment and the above range. The plurality of internal spline teeth 64 have an additional radial length RL22. The additional radial length RL22 is defined from the internal spline tooth root circle RC22 to the radially innermost ends 64A of the plurality of internal spline teeth 64 respectively. The sum of the additional radial lengths RL22 is equal to or greater than 12 mm. In this embodiment, the sum of the additional radial lengths RL22 is 27.95 mm. However, the sum of the additional radial lengths RL22 is not limited to this embodiment and the above range. At least one of the internal spline teeth 64 has an asymmetric shape relative to the circumferential tooth tip centerline CL2. The circumferential tooth tip center line CL2 is a line connecting the rotation center axis A1 and the circumferential center point CP2 of the radially innermost end 64A of the internal spline teeth 64 . However, at least one of the internal spline teeth 64 may have a symmetrical shape relative to the circumferential tooth tip centerline CL2. At least one of the internal spline teeth 64 includes an internal spline drive surface 66 and an internal spline non-drive surface 68 . Internal spline drive surface 66 has a first internal spline surface angle AG21. A first internal spline surface angle AG21 is defined between the internal spline drive surface 66 and the first radial line L21. The first radial line L21 extends from the rotational center axis A1 of the bicycle rear sprocket assembly 14 to the radially outermost edge 66A of the internal spline transmission surface 66 . The first internal pitch angle PA21 or the second internal pitch angle PA22 is defined between adjacent first radial lines L21 (see, for example, Figure 26). The internal splined non-drive surface 68 has a second internal spline surface angle AG22. A second internal spline surface angle AG22 is defined between the internal spline non-drive surface 68 and the second radial line L22. The second radial line L22 extends from the central axis of rotation A1 of the bicycle rear sprocket assembly 14 to the radially outermost edge 68A of the internal splined non-drive surface 68 . In this embodiment, the second internal spline surface angle AG22 is different from the first internal spline surface angle AG21. The first internal spline surface angle AG21 is smaller than the second internal spline surface angle AG22. However, the first internal spline surface angle AG21 may be equal to or greater than the second internal spline surface angle AG22. The first internal spline surface angle AG21 is in the range of 0 degrees to 10 degrees. The second internal spline surface angle AG22 is in the range of 0 degrees to 60 degrees. In this example, the first internal spline surface angle AG21 is 5 degrees. The second internal spline surface angle AG22 is 45 degrees. However, the first internal spline surface angle AG21 and the second internal spline surface angle AG22 are not limited to this embodiment and the above range. As seen in FIG. 30 , inner spline teeth 64 mesh with outer spline teeth 40 to transmit transmission rotational force F1 from sprocket SP1 to sprocket support body 28 . The inner splined drive surface 66 may contact the outer splined drive surface 48 to transmit the drive rotational force F1 from the sprocket SP1 to the sprocket support body 28 . In the state where the inner spline drive surface 66 is in contact with the outer spline drive surface 48 , the inner spline non-drive surface 68 is spaced apart from the outer spline non-drive surface 50 . As seen in Figure 31, sprocket SP2 includes a plurality of internal spline teeth 70. Sprocket SP3 includes a plurality of internal spline teeth 72 . Sprocket SP4 includes a plurality of internal spline teeth 74 . The first ring 59A includes a plurality of internal spline teeth 76 . As seen in FIG. 32 , the hub engaging portion 60 of the sprocket support 56 includes a plurality of internal spline teeth 78 . The plurality of internal spline teeth 70 have substantially the same structure as the plurality of internal spline teeth 64 . The plurality of internal spline teeth 72 has substantially the same structure as the plurality of internal spline teeth 64 . The plurality of internal spline teeth 74 has substantially the same structure as the plurality of internal spline teeth 64 . The plurality of internal spline teeth 76 has substantially the same structure as the plurality of internal spline teeth 64 . The plurality of internal spline teeth 78 has substantially the same structure as the plurality of internal spline teeth 64 . Therefore, for the sake of brevity, it will not be described in detail here. As used herein, the term "comprising" and its derivatives are intended to specify the presence of stated features, elements, components, groups, integers and/or steps but not to exclude the presence of other unstated features, elements, components, groups, Open term for the existence of integers and/or steps. This concept also applies to words of similar meaning, such as the terms "have", "include" and their derivatives. The terms "member", "section", "section", "part", "element", "body" and "structure" when used in the singular may have the dual meaning of a single part or a plurality of parts. Ordinal numbers such as "first" and "second" described in this application are merely identifiers and do not have any other meaning, such as a specific order and the like. Furthermore, for example, the term "first element" by itself does not imply the presence of a "second element," and the term "second element" by itself does not imply the presence of a "first element." The term "pair" as used herein may encompass configurations in which pairs of elements have different shapes or structures from each other in addition to configurations in which pairs of elements have the same shape or structure as each other. Accordingly, the terms "a," "one or more," and "at least one" are used interchangeably herein. Finally, terms of degree such as "substantially," "approximately," and "approximately" as used herein mean a reasonable amount of deviation from the modified term such that the end result does not materially alter. All numerical values described in this application may be understood to include terms such as "substantially," "approximately," and "approximately." Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.

10:Bicycle transmission system 12:Bicycle wheel hub assembly 14: Bicycle rear sprocket assembly 16:Bicycle brake rotor 18:Crank assembly 20:Bicycle chain 22:Crankshaft 24:Right crank arm 26:Left crank arm 27:Front sprocket 28: Sprocket support body 28A: Internal threaded part 30: hub shaft 30A:Through hole 30B: First shaft end 30B1: Axial contact surface 30C: Second shaft end 32:Lock ring 32A: External threaded part 32B: Locking flange 34: Brake rotor support body 36: Wheel hub body 36A:First flange 36B: Second flange 38: Ratchet structure/one-way coupling structure 39A:First bearing 39B: Second bearing 40: External spline teeth 40A: Radially outermost end 41:Base support 42: Larger diameter part 42A: Axial end 44:Flange 46:Helical external spline teeth 48: External spline drive surface 48A: Radial outermost edge 48B: Radial innermost edge 50: External splined non-drive surface 50A: Radial outermost edge 50B: Radial innermost edge 50R: reference point 52:Extra external spline teeth 54: Additional base support 56:Sprocket support 58: Spacer/Sprocket Support 58A: First spacer 58B: Second spacer 58C:Third spacer 58D: The fourth spacer 58E:Fifth spacer 58F:Sixth spacer 58G:Seventh spacer 59A:First ring 59B:Second ring 60: Hub meshing part 62:Support arm 62A: First attachment part 62B: Second attachment part 62C: Third attachment part 62D: Fourth attachment part 62E: Fifth attachment part 62F: Sixth attachment part 62G:Seventh attachment part 62H: The eighth attachment part 64: Internal spline teeth 64A: Radially innermost end 66: Internal spline transmission surface 66A: Radially outermost edge 66B: Radial innermost edge 68: Internal splined non-drive surface 68A: Radially outermost edge 68B: Radial innermost edge 68R: Reference point 70: Internal spline teeth 72: Internal spline teeth 74: Internal spline teeth 76: Internal spline teeth 78: Internal spline teeth A1: Rotation center axis AG11: First external spline surface angle AG12: Second external spline surface angle AG21: First internal spline surface angle AG22: Second internal spline surface angle AL11: first axial length AL12: Second axial length AL13: Axial length BF: bicycle frame BF1: first frame BF2: Second frame BF11: first groove BF12: Frame contact surface BF21: Second groove CL1: Circumferential tooth tip center line CL2: Circumferential tooth tip center line CP1: Circle center point CP2: Circle center point D1: Circumferential direction D2: Axial direction D11: Transmission rotation direction D12: Reverse rotation direction DM11: External spline top diameter DM12: External spline bottom diameter DM13: outer diameter DM14: Extra external spline top diameter DM21: Internal spline top diameter DM22: Internal spline bottom diameter F1: Transmission rotation force F2:Thrust F3:Thrust IV-IV: line L11: first radial line L12: Second radial line L21: first radial line L22: Second radial line MW1: maximum circumferential width MW2: maximum circumferential width PA11: First external pitch angle PA12: Second external pitch angle PA21: First internal pitch angle PA22: Second internal pitch angle RC11: First reference circle RC12: External spline root circle RC21: Second reference circle RC22: Internal spline root circle RL11: Radial length RL12: additional radial length RL21: Radial length RL22: additional radial length SP1: sprocket SP1A: sprocket body SP1B: sprocket teeth SP2: sprocket SP2A: sprocket body SP2B: sprocket teeth SP3: sprocket SP3A: sprocket body SP3B: sprocket teeth SP4: sprocket SP4A: sprocket body SP4B: sprocket teeth SP5: sprocket SP5A: sprocket body SP5B: sprocket teeth SP6: sprocket SP6A: sprocket body SP6B: sprocket teeth SP7: sprocket SP7A: sprocket body SP7B: sprocket teeth SP8: sprocket SP8A: sprocket body SP8B: sprocket teeth SP9: sprocket SP9A: sprocket body SP9B: sprocket teeth SP10: sprocket SP10A: sprocket body SP10B: sprocket teeth SP11: sprocket SP11A: sprocket body SP11B: sprocket teeth SP12: sprocket SP12A: sprocket body SP12B: sprocket teeth WS: wheel fastening structure WS1: Fastening rod XVI-XVI: line XXIII-XXIII: line

A more complete evaluation of the present invention and its many attendant advantages will readily be obtained, and likewise become better understood, with reference to the following detailed description when considered in conjunction with the accompanying drawings, in which: Figure 1 is a schematic diagram of a bicycle transmission system according to an embodiment. FIG. 2 is an exploded perspective view of the bicycle transmission system illustrated in FIG. 1 . FIG. 3 is another perspective view of the bicycle transmission system illustrated in FIG. 2 . 4 is a cross-sectional view of the bicycle transmission system taken along line IV-IV of FIG. 2 . FIG. 5 is an exploded perspective view of the bicycle hub assembly of the bicycle transmission system illustrated in FIG. 2 . FIG. 6 is an enlarged cross-sectional view of the bicycle transmission system illustrated in FIG. 4 . FIG. 7 is a perspective view of a sprocket support body of the bicycle hub assembly of the bicycle transmission system illustrated in FIG. 2 . 8 is another perspective view of the sprocket support body of the bicycle hub assembly of the bicycle transmission system illustrated in FIG. 2 . FIG. 9 is a side view of the sprocket support body illustrated in FIG. 7 . Figure 10 is a side view of the sprocket support body of the bicycle hub assembly according to the modification. FIG. 11 is an enlarged cross-sectional view of the sprocket support body illustrated in FIG. 7 . FIG. 12 is a cross-sectional view of the sprocket support body illustrated in FIG. 7 . FIG. 13 is a perspective view of the bicycle hub assembly of the bicycle transmission system illustrated in FIG. 2 . FIG. 14 is a side view of the bicycle hub assembly of the bicycle transmission system illustrated in FIG. 2 . FIG. 15 is a rear view of the bicycle hub assembly of the bicycle transmission system illustrated in FIG. 2 . Figure 16 is a cross-sectional view of the bicycle wheel hub assembly taken along line XVI-XVI of Figure 5. FIG. 17 is a side view of the bicycle rear sprocket assembly of the bicycle transmission system illustrated in FIG. 2 . FIG. 18 is an exploded perspective view of the rear sprocket assembly of the bicycle illustrated in FIG. 17 . Figure 19 is a partially exploded perspective view of the bicycle rear sprocket assembly illustrated in Figure 17. FIG. 20 is another partially exploded perspective view of the rear sprocket assembly of the bicycle illustrated in FIG. 17 . Figure 21 is another partially exploded perspective view of the bicycle rear sprocket assembly illustrated in Figure 17. Figure 22 is another partially exploded perspective view of the bicycle rear sprocket assembly illustrated in Figure 17. Figure 23 is a perspective cross-sectional view of the bicycle rear sprocket assembly taken along line XXIII-XXIII of Figure 17. Figure 24 is a perspective view of the smallest sprocket of the bicycle rear sprocket assembly illustrated in Figure 17. Figure 25 is another perspective view of the smallest sprocket of the bicycle rear sprocket assembly illustrated in Figure 17. Figure 26 is a side view of the smallest sprocket of the bicycle rear sprocket assembly illustrated in Figure 17. Figure 27 is a side view of the smallest sprocket according to the modification. Figure 28 is an enlarged cross-sectional view of the smallest sprocket illustrated in Figure 24. Figure 29 is a cross-sectional view of the smallest sprocket illustrated in Figure 24. 30 is a cross-sectional view of the sprocket support body and the smallest sprocket of the bicycle transmission system illustrated in FIG. 2 . Figure 31 is a partially exploded perspective view of the bicycle rear sprocket assembly illustrated in Figure 17. Figure 32 is a perspective view of the sprocket support member of the bicycle rear sprocket assembly illustrated in Figure 17.

28: Sprocket support body

28A: Internal threaded part

40: External spline teeth

41:Base support

42: Larger diameter part

44:Flange

46:Helical external spline teeth

A1: Rotation center axis

D2: Axial direction

Claims (37)

A bicycle wheel hub assembly, which includes: A sprocket support body including at least ten external spline teeth structured to engage a bicycle rear sprocket assembly, each of the at least ten external spline teeth having an external spline drive surface and an external splined non-drive surface. Such as the bicycle wheel hub assembly of claim 1, wherein The total number of one of the at least ten external spline teeth is equal to or greater than 20. Such as the bicycle wheel hub assembly of claim 2, wherein The total number of the at least ten external spline teeth is equal to or greater than 25. Such as the bicycle wheel hub assembly of claim 1, wherein The at least ten external spline teeth have a first external pitch angle and a second external pitch angle different from the first external pitch angle. Such as the bicycle wheel hub assembly of claim 1, wherein At least one of the at least ten external spline teeth has a first spline shape that is different from a second spline shape of another of the at least ten external spline teeth. Such as the bicycle wheel hub assembly of claim 1, wherein At least one of the at least ten external spline teeth has a first spline size that is different from a second spline size of another of the at least ten external spline teeth. Such as the bicycle wheel hub assembly of claim 1, wherein The at least ten external spline teeth each have a circumferential maximum width, and The sum of one of the largest circumferential widths is equal to or greater than 55 mm. For example, the bicycle wheel hub assembly of claim 7, wherein The sum of the maximum widths of the circles is equal to or greater than 60 mm. For example, the bicycle wheel hub assembly of claim 8, wherein The sum of the maximum widths of the circles is equal to or greater than 65 mm. A bicycle wheel hub assembly, which includes: A sprocket support body including a plurality of external spline teeth structurally designed to engage a bicycle rear sprocket assembly, at least two of the plurality of external spline teeth relative to the bicycle hub A rotation center axis of the assembly is arranged along the circumference with a first external pitch angle, and the first external pitch angle is in the range of 10 degrees to 20 degrees. For example, the bicycle wheel hub assembly of claim 10, wherein The first outer peripheral pitch angle is in the range of 12 degrees to 15 degrees. For example, the bicycle wheel hub assembly of claim 11, wherein The first outer peripheral pitch angle is in the range of 13 degrees to 14 degrees. For example, the bicycle wheel hub assembly of claim 10, wherein At least two of the plurality of external spline teeth are circumferentially arranged at a second external pitch angle relative to the rotational center axis of the bicycle hub assembly, and The second outer pitch angle is different from the first outer pitch angle. A bicycle wheel hub assembly, which includes: A sprocket support body includes at least one external spline tooth structurally designed to engage a bicycle rear sprocket assembly, the at least one external spline tooth having an external spline major diameter equal to or less than 30 mm. For example, the bicycle wheel hub assembly of claim 14 further includes: A brake rotor support body including at least one additional external spline tooth structurally designed to engage a bicycle brake rotor, the at least one additional external spline tooth having an additional external spline diameter greater than the external spline diameter diameter. For example, the bicycle wheel hub assembly of claim 14, wherein The major diameter of the external spline is equal to or greater than 25 mm. For example, the bicycle wheel hub assembly of claim 16, wherein The major diameter of the external spline is equal to or greater than 29 mm. For example, the bicycle wheel hub assembly of claim 14, wherein the at least one external spline tooth has an external spline diameter, and The external spline diameter is equal to or less than 28 mm. For example, the bicycle wheel hub assembly of claim 18, wherein The external spline diameter is equal to or greater than 25 mm. For example, the bicycle wheel hub assembly of claim 19, wherein The external spline diameter is equal to or greater than 27 mm. For example, the bicycle wheel hub assembly of claim 14, wherein The at least one external spline tooth includes a plurality of external spline teeth, the plurality of external spline teeth including a plurality of external spline transmission surfaces for receiving a transmission rotational force from the rear sprocket assembly of the bicycle during pedaling , Each of the plurality of external splined drive surfaces includes a radially outermost edge, a radially innermost edge, and a radial length defined from the radially outermost edge to the radially innermost edge, and The sum of one of the radial lengths of the plurality of external spline transmission surfaces is equal to or greater than 7 mm. For example, the bicycle wheel hub assembly of claim 21, wherein The sum of the radial lengths is equal to or greater than 10 mm. For example, the bicycle wheel hub assembly of claim 22, wherein The sum of the radial lengths is equal to or greater than 15 mm. For example, the bicycle wheel hub assembly of claim 14, wherein The sprocket support body includes a larger diameter portion having an outer diameter that is larger than the major diameter of the outer spline. For example, the bicycle wheel hub assembly of claim 24, wherein The outer diameter is in the range of 32 mm to 40 mm. For example, the bicycle wheel hub assembly of claim 24 further includes: A hub axle including an axial contact surface for contacting a bicycle frame, wherein The sprocket support body is rotatably installed on the hub shaft around a rotation center axis, a first axial length defined in an axial direction relative to the central axis of rotation from the axial contact surface to the larger diameter portion, and The first axial length is in the range of 35 mm to 41 mm. For example, the bicycle wheel hub assembly of claim 26, wherein The first axial length is equal to or greater than 39 mm. For example, the bicycle wheel hub assembly of claim 26, wherein The first axial length is in the range of 35 mm to 37 mm. For example, the bicycle wheel hub assembly of claim 26, wherein the larger diameter portion has an axial end furthest from the axial contact surface in the axial direction, a second axial length is defined in the axial direction from the axial contact surface to the axial end, and The second axial length is in the range of 38 mm to 47 mm. For example, the bicycle wheel hub assembly of claim 29, wherein The second axial length is in the range of 44 mm to 45 mm. For example, the bicycle wheel hub assembly of claim 29, wherein The second axial length is in the range of 40 mm to 41 mm. For example, the bicycle wheel hub assembly of claim 24, wherein The axial length of one of the larger diameter portions is in the range of 3 mm to 6 mm. A bicycle wheel hub assembly, which includes: A sprocket support body including at least nine external spline teeth structured to engage a bicycle rear sprocket assembly, at least one of the at least nine external spline teeth relative to a circumferential tooth tip center The wire has an asymmetric shape, and the at least one of the at least nine external spline teeth includes: An external spline drive surface having a first external spline surface angle defined between the external spline drive surface and a first radial line extending from one of the bicycle wheel hub assembly The central axis of rotation extends to one of the radially outermost edges of the external splined transmission surface; and An external splined non-drive surface having a second external spline surface angle defined between the external splined non-drive surface and a second radial line extending from the bicycle wheel hub assembly The center axis of rotation extends to a radially outermost edge of the external spline non-drive surface, and the second external spline surface angle is different from the first external spline surface angle. For example, the bicycle wheel hub assembly of claim 33, wherein The first outer spline surface angle is less than the second outer spline surface angle. For example, the bicycle wheel hub assembly of claim 33, wherein The first external spline surface angle is in the range of 0 degrees to 10 degrees. For example, the bicycle wheel hub assembly of claim 33, wherein The second external spline surface angle is in the range of 0 degrees to 60 degrees. For example, the bicycle wheel hub assembly of claim 33, wherein The at least ten external spline teeth have a first external pitch angle and a second external pitch angle different from the first external pitch angle.