TW201900444A - 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 assembly

The invention relates to a bicycle hub assembly.

Bicycling is becoming a more popular pastime and mode of transportation. In addition, cycling has become a very popular competitive sport for 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 hub assembly includes a sprocket support body. The sprocket support body includes at least ten external spline teeth that are structurally designed to mesh with 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 hub assembly according to the first aspect, at least ten external spline teeth are reduced to at least ten external splines compared to a sprocket support body including nine or fewer 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 of selecting the material of the sprocket support body without reducing the durability of the sprocket support body. According to a second aspect of the present invention, the bicycle hub assembly as in the first aspect is structurally designed so that the total number of one of the at least ten external spline teeth is equal to or greater than 20. In the case of the bicycle hub assembly according to the second aspect, at least twenty external spline teeth are further reduced to at least twenty compared to a sprocket support body including nine or fewer external spline teeth. Rotating force of each of the external spline teeth. This further improves the durability of the sprocket support body and / or improves the freedom of selecting the material of the sprocket support body without reducing the durability of the sprocket support body. According to a third aspect of the present invention, the bicycle hub assembly of the second aspect is structurally designed so 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 hub assembly according to the third aspect, at least twenty-five external spline teeth are further reduced to at least twenty compared to a sprocket support body including nine or less external spline teeth Rotating force of each of the five outer spline teeth. This further improves the durability of the sprocket support body and / or improves the freedom of selecting the material of the sprocket support body without reducing the durability of the sprocket support body. According to the fourth aspect of the present invention, the bicycle hub assembly of any one of the first aspect to the third aspect is structured so that the at least ten external spline teeth have a first external peripheral angle and A second outer perimeter angle different from one of the first outer perimeter angles. In the case of the bicycle hub assembly according to the fourth aspect, the difference between the first outer perimeter angle and the second outer perimeter angle helps the user to properly mount the bicycle rear sprocket assembly to the sprocket support body , Especially regarding the circumferential position of each sprocket in a bicycle rear sprocket assembly. According to a fifth aspect of the present invention, the bicycle hub assembly as in any one of the first aspect to the fourth aspect is structured so that at least one of the at least ten external spline teeth has a different shape from the One of the at least ten outer spline teeth is a first spline shape with a second spline shape. In the case of the bicycle 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 hub assembly as in any one of the first aspect to the fifth aspect is structured so that at least one of the at least ten external spline teeth has a different shape from the One of the at least ten outer spline teeth is a second spline size a first spline size. In the case of the bicycle hub assembly according to the sixth aspect, the difference between the size of the first spline and the size of the second spline 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 hub assembly of any one of the first aspect to the sixth aspect is structured so that the at least ten outer spline teeth each have a maximum circumferential width. The sum of one of the maximum widths of these circles is equal to or greater than 55 mm. In the case of the bicycle hub assembly according to the seventh aspect, it is possible to improve the strength in the shear direction of at least ten external spline teeth. According to an eighth aspect of the present invention, the bicycle hub assembly according to the seventh aspect is structurally designed so that the sum of the maximum widths of the circumferences is equal to or greater than 60 mm. In the case of the bicycle hub assembly according to the eighth aspect, it is possible to further improve the strength in the shear direction of at least ten external spline teeth. According to a ninth aspect of the present invention, the bicycle hub assembly according to the eighth aspect is structured so that the sum of the maximum widths of the circumferences is equal to or greater than 65 mm. In the case of the bicycle hub assembly according to the ninth aspect, it is possible to further improve the strength in the shear direction of at least ten external spline teeth. 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 that are structurally designed to mesh with a bicycle rear sprocket assembly. At least two external spline teeth of the plurality of external spline teeth are circumferentially arranged at a first external pitch angle with respect to a rotation center axis of the bicycle hub assembly. The first outer perimeter angle is in a range of 10 degrees to 20 degrees. In the case of the bicycle hub assembly according to the tenth aspect, the first external peripheral angle is reduced to be applied to at least two external portions compared to a sprocket support body having an external peripheral angle greater than the first external peripheral angle. Rotating force of each of the spline teeth. This improves the durability of the sprocket support body and / or improves the freedom of selecting the material of the sprocket support body without reducing the durability of the sprocket support body. According to the eleventh aspect of the present invention, the bicycle hub assembly according to the tenth aspect is structurally designed so that the first outer peripheral angle is in a range of 12 degrees to 15 degrees. In the case of the bicycle hub assembly according to the eleventh aspect, the first external peripheral angle is further reduced to at least two compared to a sprocket support body having an external peripheral angle greater than the first external peripheral angle. The rotational force of each of the two external spline teeth. This further improves the durability of the sprocket support body and / or improves the freedom of 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 hub assembly according to the eleventh aspect is structurally designed so that the first outer peripheral angle is in a range of 13 degrees to 14 degrees. In the case of the bicycle hub assembly according to the twelfth aspect, the first outer peripheral angle is further reduced to at least two compared to a sprocket support body having an outer peripheral angle greater than the first outer peripheral angle. The rotational force of each of the two external spline teeth. This further improves the durability of the sprocket support body and / or improves the freedom of 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 hub assembly according to any one of the tenth aspect to the twelfth aspect is structurally designed so that at least two external splines of the plurality of external spline teeth The teeth are arranged circumferentially at a second outer perimeter angle with respect to the rotation center axis of the bicycle hub assembly. The second outer perimeter angle is different from the first outer perimeter angle. In the case of the bicycle hub assembly according to the thirteenth aspect, the difference between the first outer perimeter angle and the second outer perimeter angle helps the user to properly mount the bicycle rear sprocket assembly to the sprocket support The main body, especially regarding the circumferential position of each sprocket of the bicycle rear sprocket assembly. According to a fourteenth aspect of the present invention, a bicycle hub assembly includes a sprocket support body. The sprocket support body includes at least one external spline tooth structured to mesh with a bicycle rear sprocket assembly. The at least one external spline tooth has an external spline major diameter equal to or less than 30 mm. In the case of the bicycle hub assembly according to the fourteenth aspect, the large external spline diameter enables the bicycle hub assembly to mount a bicycle rear sprocket assembly including a sprocket having ten or less sprocket teeth to Bicycle wheel 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 according to the fourteenth aspect further includes a brake rotor supporting body including at least one additional exterior structured to be engaged with a bicycle brake rotor. Spline teeth. The at least one additional external spline tooth has an additional external spline diameter that is larger than one of the external spline diameters. In the case of the bicycle hub assembly according to the fifteenth aspect, the brake rotor supporting body improves the 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 hub assembly such as the fourteenth aspect or the fifteenth aspect is structured so that the large diameter of the external spline 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 enable the bicycle hub assembly to mount a bicycle rear sprocket assembly including a sprocket having ten or less sprocket teeth to the bicycle hub. 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 according to the sixteenth aspect is structurally designed so that the large diameter of the external spline 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 enable the bicycle hub assembly to mount a bicycle rear sprocket assembly including a sprocket having ten or less sprocket teeth to the bicycle hub. In the case of the assembly, ensure the strength of the sprocket support body. According to the eighteenth aspect of the present invention, the bicycle hub assembly according to any one of the fourteenth aspect to the seventeenth aspect is structured so that the at least one external spline tooth has an external spline path , The external spline diameter is equal to or less than 28 mm. In the case of the bicycle hub assembly according to the eighteenth aspect, the external spline diameter can increase the radial length of the transmission surface of at least one external spline tooth. This improves the strength of the sprocket support body. According to a nineteenth aspect of the present invention, the bicycle hub assembly according to the eighteenth aspect is structurally designed so that the outer spline diameter 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 surely 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 the twentieth aspect of the present invention, the bicycle hub assembly according to the nineteenth aspect is structurally designed so that the outer spline diameter 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 surely 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 the twenty-first aspect of the present invention, the bicycle hub assembly according to any one of the fourteenth aspect to the twentieth aspect is structurally designed so that the at least one external spline tooth includes a plurality of external splines Teeth, the plurality of external spline teeth include a plurality of external spline drive surfaces for receiving a driving rotational force from one of the bicycle rear sprocket assemblies during pedaling. Each of the plurality of external spline transmission 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. The sum of one of the radial lengths of the plurality of external spline drive surfaces is equal to or greater than 7 mm. In the case of the bicycle hub assembly according to the twenty-first aspect, it is possible to increase the radial length of the plurality of external spline drive surfaces. This improves the strength of the sprocket support body. According to the twenty-second aspect of the present invention, the bicycle hub assembly according to the twenty-first aspect is structured so that the total of the radial lengths is equal to or greater than 10 mm. In the case of the bicycle hub assembly according to the twenty-second aspect, it is possible to further increase the radial length of the plurality of external spline drive surfaces. This further improves the strength of the sprocket support body. According to the twenty-third aspect of the present invention, the bicycle hub assembly as in the twenty-second aspect is structured so that the total of the radial lengths is equal to or greater than 15 mm. In the case of the bicycle hub assembly according to the twenty-third aspect, it is possible to further increase the radial length of the plurality of external spline drive 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 according to any one of the fourteenth aspect to the twenty-third aspect is structurally designed so that the sprocket support body includes a larger diameter portion, The larger diameter portion has an outer diameter larger than one of the larger diameters of the outer splines. In the case of the bicycle hub assembly according to the twenty-fourth aspect, it is possible to improve the design freedom of the internal structure of the bicycle hub assembly. For example, a transmission structure such as a one-way coupling structure can be housed within the internal cavity of this larger diameter portion of the sprocket support body. According to a twenty-fifth aspect of the present invention, the bicycle hub assembly according to the twenty-fourth aspect is structurally designed so that the outer diameter is in a range of 32 mm to 40 mm. In the case of the bicycle hub assembly according to the twenty-fifth aspect, it is possible to further improve the design freedom of the internal structure of the bicycle hub assembly. For example, it may be easy to place a transmission structure such as a unidirectional coupling structure in the internal cavity of this larger diameter portion. According to a twenty-sixth aspect of the present invention, the bicycle hub assembly according to the twenty-fourth aspect further includes a hub shaft including an axial contact surface for contacting a bicycle frame. The sprocket support body is rotatably mounted on the hub shaft about a rotation center axis. A first axial length is defined from the axial contact surface to the larger diameter portion in an axial direction relative to the rotation center axis. The first axial length is in the range of 35 mm to 41 mm. In the case of the bicycle hub assembly according to the twenty-sixth aspect, it is possible to secure the axial length of at least one outer spline tooth. According to the twenty-seventh aspect of the present invention, the bicycle hub assembly according to the twenty-sixth aspect is structured so that the first axial length is equal to or greater than 39 mm. In the case of the bicycle hub assembly according to the twenty-seventh aspect, it is possible to further ensure the radial length of at least one outer spline tooth. According to the twenty-eighth aspect of the present invention, the bicycle hub assembly according to the twenty-sixth aspect is structured so that the first axial length is in a range of 35 mm to 37 mm. In the case of the bicycle hub assembly according to the twenty-eighth aspect, it is possible to further secure the axial length of at least one outer spline tooth. According to the twenty-ninth aspect of the present invention, the bicycle hub assembly according to the twenty-sixth aspect is structured so that the larger diameter portion has a distance 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 the thirtieth aspect of the present invention, the bicycle hub assembly according to the twenty-ninth aspect is structurally designed so that the second axial length is in a range of 44 mm to 45 mm. In the case of the bicycle hub assembly according to the thirtieth aspect, it is possible to further 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 the thirty-first aspect of the present invention, the bicycle hub assembly according to the twenty-ninth aspect is structurally designed so that the second axial length is in a range of 40 mm to 41 mm. In the case of the bicycle hub assembly according to the thirty-first aspect, it is possible to further 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 the thirty-second aspect of the present invention, the bicycle hub assembly according to any one of the twenty-fourth aspect to the thirty-first aspect is structured so that an axial length of one of the larger diameter portions is between Within the range of 3 mm to 6 mm. In the case of the bicycle hub assembly according to the thirty-second aspect, it is possible to further improve the design freedom of the internal structure of the bicycle hub assembly. For example, a transmission structure such as a one-way coupling structure can be housed 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 hub assembly includes a sprocket support body. The sprocket support body includes at least nine external spline teeth that are structurally designed to mesh with a bicycle rear sprocket assembly. At least one of the at least nine external spline teeth has an asymmetric shape with respect 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 transmission surface has a first external spline surface angle defined between the external spline transmission surface and a first radial line, the first radial line is from a center of rotation of the bicycle hub assembly The axis extends to one of the radially outermost edges of the outer spline drive surface. The external spline non-driving surface has a second external spline surface angle defined between the external spline non-driving surface and a second radial line, the second radial line is from the bicycle hub assembly. The rotation center axis extends to a radially outermost edge of one of the outer spline non-drive surfaces. The second external spline surface angle is different from the first external 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 the thirty-fourth aspect of the present invention, the bicycle hub assembly according to the thirty-third aspect is structurally designed so 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 the thirty-fifth aspect of the present invention, the bicycle hub assembly such as the thirty-third aspect or the thirty-fourth aspect is structured so that the surface angle of the first external spline is between 0 degrees and 10 degrees. Within range. In the case of the bicycle 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 the thirty-sixth aspect of the present invention, the bicycle hub assembly according to any one of the thirty-third aspect to the thirty-fifth aspect is structured so that the surface angle of the second external spline is at 0 degrees To 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 the thirty-seventh aspect of the present invention, the bicycle hub assembly according to any one of the thirty-third aspect to the thirty-sixth aspect is structured so that the at least ten external spline teeth have a first An external perimeter angle and a second external perimeter angle different from the first external perimeter angle. In the case of the bicycle hub assembly according to the thirty-seventh aspect, the difference between the first outer perimeter angle and the second outer perimeter angle helps the user to properly mount the bicycle rear sprocket assembly to the sprocket The support body, especially with regard to the circumferential position of each sprocket of a bicycle rear sprocket assembly.

Embodiments will now be described with reference to the drawings, in which like reference numerals designate corresponding or identical elements in the various drawings. 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 mounted on the bicycle hub assembly 12. The bicycle brake rotor 16 is mounted on the bicycle 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 crank shaft 22, a right crank arm 24, a left crank arm 26, and a front sprocket 27. The right crank arm 24 and the left crank arm 26 are fastened to the crank shaft 22. The front sprocket 27 is fastened to at least one of the crank shaft 22 and the right crank arm 24. The bicycle chain 20 meshes 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. The crank assembly 18 includes a front sprocket 27 as a single sprocket in the illustrated embodiment. However, the crank assembly 18 may include a plurality of front sprockets. The 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", "horizontal", "upward" and "downward" and any other Similar directional terms refer to the directions determined based on a user (eg, a rider) sitting on a bicycle seat (not shown) and facing a handle (not shown). Therefore, these terms, when used to describe the bicycle drive system 10, the bicycle hub assembly 12 or the bicycle rear sprocket assembly 14, should be related to the bicycle drive system 10 equipped as used in an upright riding position on a horizontal surface , Bicycle hub assembly 12 or bicycle rear sprocket assembly 14 to interpret. 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 a rotation center axis A1 with respect to the bicycle frame BF (FIG. 1). The bicycle rear sprocket assembly 14 is structurally designed to mesh with the bicycle chain 20 to transmit a 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 mounted on the sprocket support body 28 to transmit a transmission rotational force F1 between the sprocket support body 28 and the bicycle rear sprocket assembly 14. The bicycle hub assembly 12 further includes a hub shaft 30. The sprocket support body 28 is rotatably mounted on the hub shaft 30 about a rotation center axis A1. The bicycle hub assembly 12 includes a lock ring 32. The lock ring 32 is fastened to the sprocket support body 28 to hold the bicycle rear sprocket assembly 14 relative to the sprocket support body 28 in an axial direction D2 parallel to the rotation center axis A1. As seen in FIG. 4, the bicycle hub assembly 12 is fastened to the bicycle frame BF by a 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 between the first shaft end 30B and the second shaft end 30C along the rotation center axis A1. 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 a wheel fastening structure WS. The wheel fastening structure WS includes a structure known in the applied bicycle. Therefore, for 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 a rotation center axis A1. The brake rotor support body 34 is coupled to the bicycle brake rotor 16 (FIG. 1) to transmit a 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 about a rotation center axis A1. In this embodiment, the sprocket support body 28 is a separate member from the hub body 36. The brake rotor support body 34 is integrally provided with the hub body 36 as a one-piece integral member. However, the sprocket support body 28 may be provided integrally with the hub body 36. The brake rotor support body 34 may be a separate member from the 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 the first flange 36A. A second spoke (not shown) is coupled to the second flange 36B. The second flange 36B is spaced 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. The lock ring 32 includes an externally threaded portion 32A. The sprocket support body 28 includes an internally threaded portion 28A. In a state where the lock ring 32 is fastened to the sprocket support body 28, the externally threaded portion 32A is in threaded engagement with the internally 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 operatively 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 so that the sprocket support body 28 together with the hub body 36 is rotated in the transmission rotation direction D11 (FIG. 5) during stepping. The ratchet structure 38 is structurally designed to allow the sprocket support body 28 to rotate relative to the hub body 36 in the reverse rotation direction D12 (FIG. 5) during idle rotation. Therefore, the ratchet structure 38 can be interpreted as a unidirectional coupling structure 38. The ratchet structure 38 includes a structure known in the bicycle field. Therefore, for 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 relative to the hub shaft 30 about a rotation center axis A1. In this embodiment, each of the sprocket support body 28, the brake rotor support body 34, and the hub body 36 is made of a metal material such as aluminum, iron, or titanium. However, at least one of the sprocket support body 28, the brake rotor support body 34, and the hub body 36 may be made of a non-metal material. As seen in FIGS. 7 and 8, the sprocket support body 28 includes at least one external spline tooth 40 that is structurally designed to engage the bicycle rear sprocket assembly 14 (FIG. 6). The sprocket support body 28 includes a plurality of external spline teeth 40 that are structurally designed to mesh with 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 that are structurally designed to mesh with the bicycle rear sprocket assembly 14 (FIG. 6). The sprocket support body 28 includes at least ten external spline teeth 40 that are structurally designed 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. The outer 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 spiral outer spline teeth 46. The larger diameter portion 42 and the flange 44 extend radially outward from the base support 41. The larger-diameter portion 42 is provided between the plurality of outer spline teeth 40 and the flange 44 in the axial direction D2. The larger-diameter portion 42 and the flange 44 are provided between the plurality of external spline teeth 40 and the plurality of spiral external spline teeth 46 in the axial direction D2. As seen in FIG. 6, the bicycle rear sprocket assembly 14 is held between the larger-diameter portion 42 and the lock flange 32B of the lock ring 32 in the axial direction D2. The larger diameter portion 42 may have an internal cavity such that a transmission structure such as a one-way coupling structure may be received within the internal cavity. As needed, the larger diameter portion 42 may be omitted from the bicycle hub assembly 12. As seen in FIG. 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 26. However, the total number of external spline teeth 40 is not limited to this embodiment and the above range. At least ten outer spline teeth 40 have a first outer peripheral angle PA11 and a second outer peripheral angle PA12. At least two outer spline teeth of the plurality of outer spline teeth 40 are arranged circumferentially at a first outer pitch angle PA11 with respect to the rotation center axis A1 of the bicycle hub assembly 12. At least two outer spline teeth of the plurality of outer spline teeth 40 are arranged circumferentially at a second outer pitch angle PA12 with respect to the rotation center axis A1 of the bicycle hub assembly 12. In this embodiment, the second outer perimeter angle PA12 is different from the first outer perimeter angle PA11. However, the second outer perimeter angle PA12 may be substantially equal to the first outer perimeter 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 outer spline teeth 40 are arranged at a second outer peripheral angle PA12 in the circumferential direction D1. However, at least two outer spline teeth of the outer spline teeth 40 may be arranged at another outer pitch angle in the circumferential direction D1. The first outer perimeter angle PA11 is in a range of 10 degrees to 20 degrees. The first outer perimeter angle PA11 is in a range of 12 degrees to 15 degrees. The first outer perimeter angle PA11 is in a range of 13 degrees to 14 degrees. In this embodiment, the first outer perimeter angle PA11 is 13.3 degrees. However, the first outer perimeter angle PA11 is not limited to this embodiment and above. The second section angle PA12 is in the range of 5 to 30 degrees. In this embodiment, the second outer perimeter angle PA12 is 26 degrees. However, the second outer perimeter angle PA12 is not limited to this embodiment and above. The outer spline teeth 40 have substantially the same shape as each other. The outer spline teeth 40 have spline sizes that are substantially the same as each other. When viewed along the rotation center axis A1, the outer spline teeth 40 have substantially the same contours as each other. 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 the other of the at least ten external spline teeth 40 . At least one of the at least ten outer spline teeth 40 may have a first spline size that is different from a second spline size of the other one of the at least ten outer spline teeth 40. When viewed along the rotation center axis A1, at least one of the at least ten outer spline teeth 40 may have a profile different from that of the other of the at least ten outer spline teeth 40. In FIG. 10, one of the external spline teeth 40 has a spline shape different from that of the other teeth of the external spline teeth 40. One of the external spline teeth 40 has a spline size different from the spline size of the other teeth in the external spline teeth 40. When viewed along the rotation center axis A1, one of the external spline teeth 40 has a profile different from that of the other teeth in the external 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 include a plurality of external spline transmission surfaces 48 for receiving a transmission rotational force F1 from the bicycle rear sprocket assembly 14 (FIG. 6) during pedaling. The plurality of external spline teeth 40 include a plurality of external spline non-drive surfaces 50. The external spline drive surface 48 may be in contact with the bicycle rear sprocket assembly 14 to receive a transmission rotational force F1 from the bicycle rear sprocket assembly 14 (FIG. 6) during pedaling. The external spline drive surface 48 faces the reverse rotation direction D12. The external spline non-drive surface 50 is provided on the opposite side of the external spline drive surface 48 in the circumferential direction D1. The outer spline non-transmission surface 50 faces the transmission rotation direction D11, so that it does not receive the transmission rotation force F1 from the bicycle rear sprocket assembly 14 during pedaling. At least ten outer spline teeth 40 each have a maximum circumferential width MW1. The outer 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 F2 applied to the external spline teeth 40. The maximum circumferential width MW1 is defined as the linear distance based on the external spline drive surface 48. The plurality of outer spline drive surfaces 48 each include a radially outermost edge 48A and a radially innermost edge 48B. The outer spline 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 spline non-drive surface 50 at a reference point 50R. The maximum circumferential width MW1 extends straight from the radially innermost edge 48B in the circumferential direction D1 to the reference point 50R. The plurality of external spline non-drive surfaces 50 each include a radially outermost edge 50A and a radially innermost edge 50B. The outer spline non-drive surface 50 extends from the radially outermost edge 50A to the radially innermost edge 50B. The reference point 50R is disposed 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 width MW1 is equal to or greater than 55 mm. The sum of the maximum circumferential width MW1 is equal to or greater than 60 mm. The sum of the maximum circumferential width 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 width MW1 is not limited to this embodiment and the above range. As seen in Figure 12, at least one outer spline tooth 40 has an outer spline large diameter DM11. The external spline major diameter DM11 is equal to or greater than 25 mm. The external spline major diameter DM11 is equal to or greater than 29 mm. The external spline major diameter DM11 is 30 mm or less. In this embodiment, the large diameter DM11 of the external spline is 29.6 mm. However, the external spline large diameter DM11 is not limited to this embodiment and above. At least one outer spline tooth 40 has an outer spline small diameter DM12. At least one external spline tooth 40 has an external spline tooth root circle RC12, and the external spline tooth root circle RC12 has an external spline small diameter DM12. However, the external spline tooth root circle RC12 may have another diameter different from the external spline small diameter DM12. The external spline diameter DM12 is equal to or less than 28 mm. The external spline diameter DM12 is equal to or greater than 25 mm. The external spline diameter DM12 is equal to or greater than 27 mm. In this embodiment, the external spline small diameter DM12 is 27.2 mm. However, the external spline small diameter DM12 is not limited to this embodiment and above. The larger diameter portion 42 has an outer diameter DM13 that is larger than the outer spline large diameter DM11. The outer diameter DM13 is in the range of 32 mm to 40 mm. In this embodiment, 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 external spline drive surfaces 48 each include a radial length RL11 defined 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 drive surfaces 48 is equal to or greater than 7 mm. The total of the radial length RL11 is equal to or greater than 10 mm. The total of the radial length 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 outer spline teeth 40 have an additional radial length RL12. The extra radial length RL12 is defined from the outer spline tooth root circle RC12 to the radially outermost end 40A of the plurality of outer spline teeth 40, respectively. 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 outer spline teeth 40 has an asymmetric shape with respect to the circumferential tooth tip center line 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 tooth 40. However, at least one of the outer spline teeth 40 may have a symmetrical shape with respect to the circumferential tooth tip center line 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. The external spline drive surface 48 has a first external spline surface angle AG11. The first external spline surface angle AG11 is defined between the external spline transmission surface 48 and the first radial line L11. The first radial line L11 extends from the rotation 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 perimeter angle PA11 or the second outer perimeter angle PA12 is defined between adjacent first radial lines L11 (see, for example, FIG. 9). The external spline non-drive surface 50 has a second external spline surface angle AG12. The second external spline surface angle AG12 is defined between the external spline non-drive surface 50 and the second radial line L12. The second radial line L12 extends from the rotation center axis A1 of the bicycle hub assembly 12 to the radially outermost edge 50A of the outer spline non-transmission surface 50. In this embodiment, the second external spline surface angle AG12 is different from the first external spline surface angle AG11. The first external spline surface angle AG11 is smaller than the second external spline surface angle AG12. However, the first external spline surface angle AG11 may be equal to or larger than the second external spline surface angle AG12. The first external spline surface angle AG11 is in a range of 0 to 10 degrees. The second external spline surface angle AG12 is in the range of 0 to 60 degrees. In this embodiment, the first external 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 FIGS. 13 and 14, the brake rotor support body 34 includes at least one additional external spline tooth 52 that is structurally designed to mesh with the bicycle brake rotor 16 (FIG. 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 rotation center axis A1. The additional outer spline teeth 52 extend radially outward 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 diameter DM14. As seen in FIG. 15, the additional external spline diameter DM14 is larger than the external spline diameter DM11. The additional outer spline large diameter DM14 is substantially equal to the outer diameter DM13 of the larger diameter portion 42. However, the additional external spline diameter DM14 may be equal to or smaller than the external spline diameter DM11. The additional outer spline large diameter DM14 may be different from the outer diameter DM13 of the larger diameter portion 42. As seen in FIG. 16, the hub shaft 30 includes an axial contact surface 30B1 to contact 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 from the axial contact surface 30B1 to the larger diameter portion 42 in the axial direction D2 with respect to the rotation center axis A1. 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 can 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 embodiment, 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 FIG. 17, the bicycle rear sprocket assembly 14 includes at least one sprocket. At least one sprocket includes a minimum sprocket SP1 and a maximum sprocket SP12. The smallest sprocket SP1 may also be referred to as a sprocket SP1. The largest sprocket SP12 can also be called a sprocket SP12. In this embodiment, at least one sprocket further includes sprocket SP2 to SP11. The sprocket SP1 corresponds to a high-speed gear. The sprocket SP12 corresponds to a low-speed gear. The total number of sprocket wheels 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 ten. 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 range. The sprocket SP2 includes at least one sprocket tooth SP2B. The sprocket SP3 includes at least one sprocket tooth SP3B. The sprocket SP4 includes at least one sprocket tooth SP4B. The sprocket SP5 includes at least one sprocket tooth SP5B. The sprocket SP6 includes at least one sprocket tooth SP6B. The sprocket SP7 includes at least one sprocket tooth SP7B. The sprocket SP8 includes at least one sprocket tooth SP8B. The sprocket SP9 includes at least one sprocket tooth SP9B. The sprocket SP10 includes at least one sprocket tooth SP10B. The 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 fourteen. The total number of at least one sprocket tooth SP4B is sixteen. 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 sprocket SP2 to SP11 is not limited to this embodiment. As seen in FIG. 18, the sprockets SP1 to SP12 are separate members. 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, the sprockets SP1 to SP12 are attached to the 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. The 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 the sprocket SP3 and the sprocket SP4. The second ring 59B is provided between the sprocket SP4 and the sprocket 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. The 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. The 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. The 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, and a plurality of sixths. The spacer 58F and the plurality of seventh spacers 58G. As seen in FIG. 23, the first spacer 58A is disposed between the sprocket SP5 and the sprocket SP6. The second spacer 58B is provided between the sprocket SP6 and the sprocket SP7. The third spacer 58C is provided between the sprocket SP7 and the sprocket SP8. The fourth spacer 58D is provided between the sprocket SP8 and the sprocket 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. The sprocket SP6 and the first spacer 58A are attached to the first attachment portion 62A by an adhesive structure such as an adhesive. The sprocket SP7 and the second spacer 58B are attached to the second attachment portion 62B by an adhesive structure such as an adhesive. The sprocket SP8 and the third spacer 58C are attached to the third attachment portion 62C by an adhesive structure such as an adhesive. The sprocket SP9 and the fourth spacer 58D are attached to the fourth attachment portion 62D by an adhesive structure such as an adhesive. The sprocket SP10 and the fifth spacer 58E are attached to the fifth attachment portion 62E by an adhesive structure such as an adhesive. The sprocket SP11 and the sixth spacer 58F are attached to the sixth attachment portion 62F by an adhesive structure such as an adhesive. The sprocket SP12 and the seventh spacer 58G are attached to the seventh attachment portion 62G by an adhesive structure such as an adhesive. The sprocket SP5 and the second ring 59B are attached to the eighth attachment portion 62H by an adhesive structure such as an adhesive. The hub engaging portion 60, the sprockets SP1 to SP4, the first ring 59A, and the second ring 59B are held between the larger-diameter portion 42 and the locking flange 32B of the lock ring 32 in the axial direction D2. 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 made at least partially of a non-metal 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 made at least partially of a metal material such as aluminum, iron, or titanium. The at least one sprocket includes at least one internal spline tooth configured to mesh with the bicycle hub assembly 12. As seen in FIGS. 24 and 25, at least one sprocket includes at least ten internal spline teeth that are structurally designed to mesh with the bicycle hub assembly 12. At least one internal spline tooth includes a plurality of internal spline teeth. Thus, at least one sprocket includes a plurality of internal spline teeth that are structurally designed to mesh with the bicycle hub assembly 12. In this embodiment, the sprocket SP1 includes at least ten internal spline teeth 64 that are structurally designed to mesh with the bicycle hub assembly 12. In this embodiment, the sprocket SP1 includes an internal spline tooth 64 that is structured to mesh with the external spline tooth 40 of the sprocket support body 28 of the bicycle hub assembly 12. The sprocket body SP1A has a ring shape. The internal spline teeth 64 extend radially inward from the sprocket body SP1A. As seen in FIG. 26, the total number of at least ten internal spline teeth 64 is equal to or greater than 20. 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 26. However, the total number of internal spline teeth 64 is not limited to this embodiment and the above range. At least ten internal spline teeth 64 have a first internal peripheral angle PA21 and a second internal peripheral angle PA22. At least two of the plurality of internal spline teeth 64 are arranged circumferentially with respect to the rotation center axis A1 of the bicycle rear sprocket assembly 14 at the first internal pitch angle PA21. At least two of the plurality of internal spline teeth 64 are arranged circumferentially at a second internal peripheral angle PA22 with respect to the rotation center axis A1. In this embodiment, the second internal perimeter angle PA22 is different from the first internal perimeter angle PA21. However, the second internal perimeter angle PA22 may be substantially equal to the first internal perimeter angle PA21. In this embodiment, the internal spline teeth 64 are arranged circumferentially at the first internal pitch angle PA21 in the circumferential direction D1. Two of the internal spline teeth 64 are arranged at the second internal peripheral angle PA22 in the circumferential direction D1. However, at least two of the internal spline teeth 64 may be arranged at another internal peripheral angle in the circumferential direction D1. The first internal perimeter angle PA21 is in a range of 10 to 20 degrees. The first internal perimeter angle PA21 is in a range of 12 degrees to 15 degrees. The first internal perimeter angle PA21 is in a range of 13 degrees to 14 degrees. In this embodiment, the first internal perimeter angle PA21 is 13.3 degrees. However, the first internal perimeter angle PA21 is not limited to this embodiment and above. The second inner perimeter angle PA22 is in a range of 5 to 30 degrees. In this embodiment, the second inner perimeter angle PA22 is 26 degrees. However, the second internal perimeter 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 the other one 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 the other one 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 the other one of the at least ten internal spline teeth 64. However, as seen in FIG. 27, the internal spline teeth 64 may have the same shape as each other. The internal spline teeth 64 may have the same size as each other. The internal spline teeth 64 may have the same cross-sectional shape as each other. As seen in FIG. 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 include a plurality of internal spline transmission surfaces 66 to receive a transmission rotational force F1 from the bicycle hub assembly 12 (FIG. 6) during pedaling. The plurality of internal spline teeth 64 include a plurality of internal spline non-drive surfaces 68. The internal spline transmission surface 66 may be in contact with the sprocket support body 28 to transmit a transmission rotational force F1 from the sprocket SP1 to the sprocket support body 28 during stepping. The internal spline drive surface 66 faces the drive rotation direction D11. The internal spline non-drive surface 68 is provided on the opposite side of the internal spline drive surface 66 in the circumferential direction D1. The internal spline non-transmission surface 68 faces the reverse rotation direction D12, so that the transmission rotational force F1 is not transmitted from the sprocket SP1 to the sprocket support body 28 during stepping. 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 maximum circumferential width MW2 is defined as the maximum width that receives the thrust force F3 applied to the internal spline teeth 64. The maximum circumferential width MW2 is defined as the linear distance based on the internal spline drive surface 66. The internal spline drive surface 66 includes a radially outermost edge 66A and a radially innermost edge 66B. The internal spline drive surface 66 extends from the radially outermost edge 66A to the 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 spline non-drive surface 68 at a 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. The reference point 68R is provided between the radially outermost edge 68A and the radially innermost edge 68B. The sum of the maximum circumferential width MW2 is equal to or greater than 40 mm. The sum of the maximum circumferential width MW2 is equal to or greater than 45 mm. The sum of the maximum circumferential width 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 total of the maximum circumferential width MW2 is not limited to this embodiment. As seen in FIG. 29, at least one internal spline tooth 64 has an internal spline small diameter DM21. At least one internal spline tooth 64 has an internal spline tooth root circle RC22, and the internal spline tooth root circle RC22 has an internal spline small diameter DM21. However, the internal spline tooth root circle RC22 may have another diameter different from the internal spline small diameter DM21. The internal spline diameter DM21 is equal to or less than 30 mm. The internal spline diameter DM21 is equal to or greater than 25 mm. The internal spline diameter DM21 is equal to or greater than 29 mm. In this embodiment, the internal spline minor diameter DM21 is 29.8 mm. However, the internal spline small diameter DM21 is not limited to this embodiment and above. At least one internal spline tooth 64 has an internal spline large diameter DM22 equal to or less than 28 mm. The internal spline major diameter DM22 is equal to or greater than 25 mm. The internal spline major diameter DM22 is equal to or greater than 27 mm. In this embodiment, the internal spline large diameter DM22 is 27.7 mm. However, the internal spline large diameter DM22 is not limited to this embodiment and above. As seen in FIG. 28, the plurality of internal spline drive surfaces 66 include a radially outermost edge 66A and a radially innermost edge 66B. Each of the plurality of internal spline drive surfaces 66 includes a radial length RL21 defined 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 drive surfaces 66 is equal to or greater than 7 mm. The total of the radial length RL21 is equal to or greater than 10 mm. The total of the radial length RL21 is equal to or greater than 15 mm. In this embodiment, the total of the radial length RL21 is 19.5 mm. However, the total of the 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 extra radial length RL22 is defined from the inner spline tooth root circle RC22 to the radially innermost end 64A of the plurality of inner 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 with respect to the circumferential tooth tip center line 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 tooth 64. However, at least one of the internal spline teeth 64 may have a symmetrical shape with respect to the circumferential tooth tip center line 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. The internal spline drive surface 66 has a first internal spline surface angle AG21. The first internal spline surface angle AG21 is defined between the internal spline transmission surface 66 and the first radial line L21. The first radial line L21 extends from the rotation 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 inner perimeter angle PA21 or the second inner perimeter angle PA22 is defined between adjacent first radial lines L21 (see, for example, FIG. 26). The internal spline non-drive surface 68 has a second internal spline surface angle AG22. The 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 rotation center axis A1 of the bicycle rear sprocket assembly 14 to the radially outermost edge 68A of the internal spline non-transmission 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 larger than the second internal spline surface angle AG22. The first internal spline surface angle AG21 is in a range of 0 to 10 degrees. The second internal spline surface angle AG22 is in a range of 0 to 60 degrees. In this embodiment, 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, the internal spline teeth 64 mesh with the external spline teeth 40 to transmit the transmission rotational force F1 from the sprocket SP1 to the sprocket support body 28. The internal spline transmission surface 66 may be in contact with the external spline transmission surface 48 to transmit a transmission rotational force F1 from the sprocket SP1 to the sprocket support body 28. In a state where the internal spline drive surface 66 is in contact with the external spline drive surface 48, the internal spline non-drive surface 68 is spaced from the external spline non-drive surface 50. As seen in FIG. 31, the sprocket SP2 includes a plurality of internal spline teeth 70. The sprocket SP3 includes a plurality of internal spline teeth 72. The 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 structure of the plurality of internal spline teeth 64. The plurality of internal spline teeth 72 have substantially the same structure as the structure of the plurality of internal spline teeth 64. The plurality of internal spline teeth 74 have substantially the same structure as the structure of the plurality of internal spline teeth 64. The plurality of internal spline teeth 76 have substantially the same structure as the structure of the plurality of internal spline teeth 64. The plurality of internal spline teeth 78 have substantially the same structure as the structure of the plurality of internal spline teeth 64. Therefore, for brevity, it will not be described in detail here. The term "comprising" and its derivatives, as used herein, are intended to specify the existence of stated features, elements, components, groups, integers, and / or steps but do not exclude other unstated features, components, components, groups, groups, Open term for the presence of integers and / or steps. This concept also applies to words of similar meaning, such as the terms "having", "including" and their derivatives. The terms "component", "section", "section", "component", "component", "body" and "structure" when used in the singular can have the dual meaning of a single component or a plurality of components. Ordinal numbers such as "first" and "second" described in this application are merely identifiers and have no other meaning, such as a specific order and the like. Further, for example, the term "first element" itself does not imply the existence of a "second element", and the term "second element" itself does not imply the existence of a "first element". The term "pair" as used herein may encompass configurations in which the paired elements have different shapes or structures from each other, except for configurations in which the paired elements have the same shape or structure as each other. Thus, 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 of the modified term such that the end result has not changed significantly. All numerical values described in this application can be understood to include terms such as "substantially", "about" and "approximately". Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It should therefore be understood that the invention may be practiced in other ways than that specifically described herein within the scope of the appended patent applications.

10‧‧‧ Bicycle Transmission System

12‧‧‧ Bicycle wheel assembly

14‧‧‧ Bicycle rear sprocket assembly

16‧‧‧ Bicycle brake rotor

18‧‧‧ crank assembly

20‧‧‧ Bicycle chain

22‧‧‧ crank shaft

24‧‧‧Right crank arm

26‧‧‧Left crank arm

27‧‧‧ front sprocket

28‧‧‧Sprocket support body

28A‧‧‧Internal threaded part

30‧‧‧ hub axle

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 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‧‧‧ Radial outermost

41‧‧‧ base support

42‧‧‧large diameter part

42A‧‧‧ axial end

44‧‧‧ flange

46‧‧‧ Spiral external spline teeth

48‧‧‧ external spline drive surface

48A‧‧‧Radial outermost edge

48B‧‧‧ Radial innermost edge

50‧‧‧ external spline non-drive surface

50A‧‧‧Radial outermost edge

50B‧‧‧ Radial innermost edge

50R‧‧‧Reference point

52‧‧‧ Extra external spline teeth

54‧‧‧ Extra base support

56‧‧‧Sprocket support

58‧‧‧spacer / sprocket support

58A‧‧‧First spacer

58B‧‧‧Second spacer

58C‧‧‧The third spacer

58D‧‧‧Fourth spacer

58E‧‧‧Fifth spacer

58F‧‧‧ Sixth spacer

58G‧‧‧Seventh spacer

59A‧‧‧First Ring

59B‧‧‧Second Ring

60‧‧‧Wheel meshing part

62‧‧‧ support arm

62A‧‧‧First Attachment

62B‧‧‧Second Attachment

62C‧‧‧ Third Attachment

62D‧‧‧Fourth Attachment

62E‧‧‧Fifth Attachment

62F‧‧‧ Sixth Attachment

62G‧‧‧Seventh Attachment

62H‧‧‧Eighth Attachment

64‧‧‧ Internal spline teeth

64A‧‧‧ Radial innermost

66‧‧‧ Internal spline drive surface

66A‧‧‧Radial outermost edge

66B‧‧‧ Radial innermost edge

68‧‧‧ Internal spline non-drive surface

68A‧‧‧Radial 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 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 Framework

BF11‧‧‧First groove

BF12‧‧‧Frame contact surface

BF21‧‧‧Second groove

CL1‧‧‧Circular tooth tip centerline

CL2‧‧‧Circular tooth tip centerline

CP1‧‧‧circle center point

CP2‧‧‧circle center point

D1‧‧‧ circumferential direction

D2‧‧‧ axial direction

D11‧‧‧Drive rotation direction

D12‧‧‧Reverse rotation direction

DM11‧‧‧External spline diameter

DM12‧‧‧External Spline Trail

DM13‧‧‧ Outside diameter

DM14‧‧‧Extra external spline diameter

F1‧‧‧Drive rotation force

F2‧‧‧thrust

F3‧‧‧thrust

IV-IV‧‧‧line

L11‧‧‧The first radial line

L12‧‧‧Second radial line

L21‧‧‧First radial line

L22‧‧‧ Second radial line

MW1‧‧‧Circumference maximum width

MW2‧‧‧Circumference maximum width

PA11‧‧‧First external week angle

PA12‧‧‧Second Outer Corner

PA21‧‧‧First internal week angle

PA22‧‧‧Second Internal Week Angle

RC11‧‧‧First reference circle

RC12‧‧‧External spline tooth root circle

RC21‧‧‧Second Reference Circle

RC22‧‧‧Internal spline tooth root circle

RL11‧‧‧Radial length

RL12‧‧‧Extra radial length

RL21‧‧‧Radial length

RL22‧‧‧Extra 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 lever

XVI-XVI‧‧‧line

XXIII-XXIII‧‧‧line

When considered in conjunction with the drawings, with reference to the following detailed description, a more complete evaluation of the present invention and many of its accompanying advantages will be readily available and also better understood, where: FIG. 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. 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 a 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. 7 is a perspective view of a sprocket support body of a bicycle hub assembly of the bicycle transmission system illustrated in FIG. 2. 8 is another perspective view of a sprocket support body of a 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. FIG. 10 is a side view of a sprocket support body of a bicycle hub assembly according to a 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 a bicycle hub assembly of the bicycle transmission system illustrated in FIG. 2. 14 is a side view of a 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. FIG. 16 is a cross-sectional view of the bicycle hub assembly taken along the line XVI-XVI of FIG. 5. 17 is a side view of a bicycle rear sprocket assembly of the bicycle transmission system illustrated in FIG. 2. FIG. 18 is an exploded perspective view of the bicycle rear sprocket assembly illustrated in FIG. 17. FIG. 19 is a partially exploded perspective view of the bicycle rear sprocket assembly illustrated in FIG. 17. 20 is an exploded perspective view of another portion of the bicycle rear sprocket assembly illustrated in FIG. 17. 21 is an exploded perspective view of another part of the bicycle rear sprocket assembly illustrated in FIG. 17. 22 is an exploded perspective view of another portion of the bicycle rear sprocket assembly illustrated in FIG. 17. FIG. 23 is a perspective cross-sectional view of the bicycle rear sprocket assembly taken along the line XXIII-XXIII of FIG. 17. FIG. 24 is a perspective view of the smallest sprocket of the bicycle rear sprocket assembly illustrated in FIG. 17. 25 is another perspective view of the smallest sprocket of the bicycle rear sprocket assembly illustrated in FIG. 17. FIG. 26 is a side view of the smallest sprocket of the bicycle rear sprocket assembly illustrated in FIG. 17. Figure 27 is a side view of the smallest sprocket according to the modification. FIG. 28 is an enlarged cross-sectional view of the smallest sprocket illustrated in FIG. 24. FIG. 29 is a cross-sectional view of the smallest sprocket illustrated in FIG. 24. FIG. 30 is a cross-sectional view of the sprocket support body and the smallest sprocket of the bicycle transmission system illustrated in FIG. 2. FIG. 31 is a partially exploded perspective view of the bicycle rear sprocket assembly illustrated in FIG. 17. 32 is a perspective view of a sprocket support of the bicycle rear sprocket assembly illustrated in FIG. 17.

Claims (37)

A bicycle hub assembly includes: a sprocket support body including at least ten external spline teeth that are structurally designed to mesh with a bicycle rear sprocket assembly, each of the at least ten external spline teeth One has an external spline drive surface and an external spline non-drive surface. As in the bicycle 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. As in the bicycle hub assembly of claim 2, wherein the total number of the at least ten external spline teeth is equal to or greater than 25. The bicycle hub assembly of claim 1, wherein the at least ten external spline teeth have a first external peripheral angle and a second external peripheral angle different from the first external peripheral angle. The bicycle hub assembly of claim 1, wherein at least one of the at least ten external spline teeth has a second spline shape different from one of the other of the at least ten external spline teeth. One spline shape. As in the bicycle hub assembly of claim 1, wherein at least one of the at least ten external spline teeth has a second spline size different from one of the other of the at least ten external spline teeth. One spline size. As in the bicycle hub assembly of claim 1, wherein the at least ten outer spline teeth each have a maximum circumferential width, and a sum of one of the maximum circumferential widths is equal to or greater than 55 mm. If the bicycle hub assembly of claim 7, wherein the sum of the maximum circumferential widths is equal to or greater than 60 mm. If the bicycle hub assembly of claim 8, wherein the sum of the maximum widths of the circumferences is equal to or greater than 65 mm. A bicycle hub assembly includes: a sprocket support body including a plurality of external spline teeth that are structurally designed to mesh with a bicycle rear sprocket assembly, and at least two of the plurality of external spline teeth The external spline teeth are arranged along the circumference with a first external peripheral angle with respect to a rotation center axis of the bicycle hub assembly, and the first external peripheral angle is in a range of 10 degrees to 20 degrees. The bicycle hub assembly of claim 10, wherein the first outer perimeter angle is in a range of 12 degrees to 15 degrees. The bicycle hub assembly of claim 11, wherein the first outer perimeter angle is in a range of 13 degrees to 14 degrees. For example, the bicycle hub assembly of claim 10, wherein at least two external spline teeth of the plurality of external spline teeth are arranged circumferentially at a second external pitch angle with respect to the rotation center axis of the bicycle hub assembly. And the second outer perimeter angle is different from the first outer perimeter angle. A bicycle hub assembly includes: a sprocket support body including at least one external spline tooth that is structurally designed to mesh with a bicycle rear sprocket assembly, the at least one external spline tooth having an equal or less than 30 One of the outer diameter of the spline is large. The bicycle hub assembly of claim 14, further comprising: a brake rotor support body including at least one additional external spline tooth configured to mesh with a bicycle brake rotor, the at least one additional external spline tooth having An additional external spline diameter is greater than one of the external spline diameters. The bicycle hub assembly of claim 14, wherein the large diameter of the external spline is equal to or greater than 25 mm. The bicycle hub assembly of claim 16, wherein the large diameter of the external spline is equal to or greater than 29 mm. The bicycle 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. The bicycle hub assembly of claim 18, wherein the external spline diameter is equal to or greater than 25 mm. The bicycle hub assembly of claim 19, wherein the external spline diameter is equal to or greater than 27 mm. The bicycle 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 includes one of the rear sprockets for receiving from the bicycle during pedaling A plurality of external spline drive surfaces for transmitting rotational force, each of the plurality of external spline drive surfaces includes a radial outermost edge, a radial innermost edge, and a radial length from the radial outermost The edge is defined to the radially innermost edge, and the sum of one of the radial lengths of the plurality of outer spline drive surfaces is equal to or greater than 7 mm. If the bicycle hub assembly of claim 21, wherein the sum of the radial lengths is equal to or greater than 10 mm. If the bicycle hub assembly of claim 22, wherein the sum of the radial lengths is equal to or greater than 15 mm. The bicycle hub assembly of claim 14, wherein the sprocket support body includes a larger diameter portion having an outer diameter larger than one of the larger diameters of the outer splines. The bicycle hub assembly of claim 24, wherein the outer diameter is in the range of 32 mm to 40 mm. The bicycle hub assembly of claim 24, further comprising: a hub shaft including an axial contact surface for contacting a bicycle frame, wherein the sprocket support body is rotatably mounted on the rotation center axis On the hub shaft, a first axial length is defined from the axial contact surface to the larger diameter portion in an axial direction relative to the rotation center axis, and the first axial length is 35 mm to 41 mm Within range. The bicycle hub assembly of claim 26, wherein the first axial length is equal to or greater than 39 mm. The bicycle hub assembly of claim 26, wherein the first axial length is in a range of 35 mm to 37 mm. The bicycle hub assembly of claim 26, wherein the larger diameter portion has an axial end furthest from the axial contact surface in the axial direction, and a second axial length is in the axial direction It is defined from the axial contact surface to the axial end, and the second axial length is in a range of 38 mm to 47 mm. The bicycle hub assembly of claim 29, wherein the second axial length is in a range of 44 mm to 45 mm. The bicycle hub assembly of claim 29, wherein the second axial length is in a range of 40 mm to 41 mm. The bicycle hub assembly of claim 24, wherein an axial length of one of the larger diameter portions is in a range of 3 mm to 6 mm. A bicycle hub assembly includes: a sprocket support body including at least nine external spline teeth that are structurally designed to mesh with a bicycle rear sprocket assembly, and at least nine of the at least nine external spline teeth One has an asymmetric shape with respect to a circumferential tooth tip centerline, and the at least one of the at least nine external spline teeth includes: an external spline drive surface having a surface defined by the external spline drive surface and A first external spline surface angle between a first radial line extending from a rotation center axis of the bicycle hub assembly to a radially outermost edge of the external spline transmission surface ; And an external spline non-driving surface having a second external spline surface angle defined between the external spline non-driving surface and a second radial line from the bicycle hub In general, the rotation center axis extends to a radially outermost edge of the non-transmission surface of the external spline, and the second external spline surface angle is different from the first external spline surface angle. The bicycle hub assembly of claim 33, wherein the first external spline surface angle is smaller than the second external spline surface angle. The bicycle hub assembly of claim 33, wherein the first external spline surface angle is in a range of 0 to 10 degrees. The bicycle hub assembly of claim 33, wherein the second external spline surface angle is in a range of 0 to 60 degrees. The bicycle hub assembly of claim 33, wherein the at least ten external spline teeth have a first external peripheral angle and a second external peripheral angle different from the first external peripheral angle.