GB862910A - Improvements in or relating to pneumatic tyres for vehicle wheels - Google Patents

Abstract

862,910. Tyre treads. PIRELLI S.p.A. June 20, 1958 [April 2, 1958], No. 19836/58. Class 144 (2). A pneumatic tyre has a tread A comprising at least one pair of main circumferential rows 1, 2, 3, 4 of blocks disposed symmetrically one wholly on each side of the mid-plane of the tyre with the blocks of the or each pair of main rows being relatively circumferentially staggered, and a pair of subsidiary circumferential rows of blocks 20 disposed symmetrically one upon each side of the mid-plane with their blocks transversely aligned, each block of the main rows being transversely aligned, and coextensive circumferentially, with two successive blocks in the adjacent subsidiary row. As shown, each block in the main rows is of rectangular shape with two recesses 10, 11 in that side thereof facing the mid-plane of the tyre. Adjacent blocks 20 are separated from each other by a block 21 of smaller transverse width and circumferential length, but of the same radial height as the blocks 20, recesses 22 and 23 extending into the shoulders B, C serving to separate each block 21 from the adjacent blocks 20. The shoulders B, C comprise blocks 30 continuous with the blocks 20 and separated from each other by recesses 33. Each shoulder portion of the tyre comprises also concentric circumferential ribs 31, 32.