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"For sprockets of different diameters, small rings D are used, of different diameters. The nut C is screwed on and off by a wrench; it has grooves, in order to get rid of the turnings that fall on the threads of the studs." —Grimshaw, 1902

Bicycle Sprockets Gear

"For sprockets of different diameters, small rings D are used, of different diameters. The nut C is…