Cassettes
Used MTB cassettes from UK sellers — Shimano, SRAM, SunRace and e*thirteen, matched to your drivetrain speed and freehub body type. The cassette determines your gear range and wears alongside the chain, so check the pair together.
What gear range do I need?
The cassette defines your gear range — how easy your easiest gear is and how fast you can pedal on the flat. Modern 1x drivetrains rely on wide-range cassettes (10-51T or 10-52T) to compensate for having a single chainring up front. 10-speed cassettes (11-42T typical) give adequate range for most trail riding, but the gear jumps between sprockets are larger; 11-speed (11-46T or 10-46T) is the sweet spot of range and gear spacing; 12-speed (10-51T Shimano, 10-52T SRAM) is the widest range available, with a genuine climbing gear and tighter spacing between gears.
Is it worth upgrading to 12-speed?
For new builds, 12-speed is the standard. For existing bikes, upgrading from 10 to 12-speed usually requires a new shifter, derailleur, chain, cassette and potentially a new freehub body, so price the full set of MTB components before you commit to the cassette.
Will it fit my freehub?
This is the most common compatibility trap — unlike a set of pedals, a cassette is not a universal fit. Shimano HG (Hyperglide) fits most 10 and 11-speed cassettes, SRAM XD (XDR) is required for SRAM 12-speed Eagle cassettes, and Shimano Micro Spline is required for Shimano 12-speed cassettes. Your hub's freehub body determines which cassettes you can run; some hubs (Hope, DT Swiss, Industry Nine) offer swappable freehub bodies, so buy the right freehub driver for your cassette choice.
Steel, alloy or titanium?
Steel cassettes are heavy but durable — Shimano Deore 12-speed (CS-M6100) weighs around 470g but lasts well. Alloy and titanium sprockets on higher-end cassettes (XT, XTR, SRAM XX1) reduce weight significantly, down to 230g for XTR, but wear faster and cost substantially more. For most riders, mid-range cassettes offer the best value: SLX or GX Eagle hit a good weight-to-durability ratio. Save the lightweight cassettes for race day.
How do I tell if a used cassette is worn?
A worn cassette causes skipping under load — the chain rides up over the worn teeth instead of engaging cleanly. If you replace a chain and it skips on the cassette, the cassette is done. Replacing the chain on time (at 0.5% wear) extends cassette life significantly: you should get two or three chains through one cassette if you stay on top of chain replacement.