Install a new rear cassette and freewheel to keep your gears turning smoothly. Fitting on the rear wheel, cassettes (and the freewheel bodies they are mounted on) typically have between seven and ten cogs, giving a wide range of gear ratios. However, with use the teeth can become worn down, possibly leading to gears jumping and skipping.
For mountain bikes, cassettes are traditionally 7-speed, 8-speed, or 9-speed, but are increasingly moving towards 12 cogs in newer systems from Shimano and SRAM. Meanwhile, 8-speed freewheel, 9-speed and 10-speed road bike cassettes are available from these manufacturers and also from Campagnolo. We also stock multi-speed freewheels, which tend to be found on budget bikes, and BMX freewheels, and single speed cassettes.