Cassette
drivetrain
A cassette is the cluster of sprockets (cogs) on the rear wheel that the chain shifts between. Modern road cassettes typically have 11 or 12 cogs; mountain bike cassettes commonly have 12.
Key cassette specs:
- Speed count — number of cogs (e.g. 11-speed, 12-speed)
- Range — smallest to largest cog (e.g. 11–28t, 10–36t)
- Step size — gap between consecutive cogs (closer steps = smoother cadence transitions)
- Freehub standard — the spline pattern that engages the rear hub (HG, Micro Spline, XD/XDR, etc.)
Cassettes are wear items. They typically last 2–4 chains' worth of mileage if chains are replaced before they wear excessively.
See also: Chainring, Freehub Body.
