guide
what changing sprockets does
The final ratio is the rear teeth divided by the front teeth: 42 ÷ 14 = 3.00.
- 01
A higher ratio (one tooth less at the front, or more at the rear) is shorter gearing: stronger pull and more engine revs at the same speed, with a lower top speed. A lower ratio does the opposite.
- 02
If the speed sensor reads the gearbox output, the speedometer is off by the same percentage as the ratio changes. If it reads the front wheel, sprockets do not change it.
- 03
Bigger sprockets need a longer chain. The Drive kit calculator works out the links from your present chain so the rear axle stays about where it is now.
Source: ANSI/ASME B29.1 and ISO 606 roller chain series (1/2 in and 5/8 in pitch)