Bicycle drive with small dia. sprockets - of pitch less than 12.7 millimetres and drive chain with equal or integral multiple pitch

摘要

Bicycle gears in which the diameter of the sprockets is reduced below that of conventional devices, comprises a front driving gear (1) mounted on a crank (11), a rear driven gear (2), with a drive chain (3) engaging both gears. The sprockets on both gears (1a, 2a) have teeth with a pitch of less than 12.7 mm - pref. from 8.5 mm to 11.5 mm - and the chain has a pitch equal to, or an integral multiple of that of the sprocket teeth. The device gives lower running resistance with improved acceleration and increased transmission ratio without increasing the diameter of the driving gear.