Cranksets
Used mountain bike cranksets from UK sellers, including Shimano, SRAM, Race Face, Hope, Rotor and e*thirteen. The crank arms and spindle transfer your pedalling power to the chainring, so match the spindle interface, arm length and chainring mount to your bottom bracket and frame.
What does a crankset need to match?
The crankset is the lever arm between your feet and the chainring. Unlike most components it interacts directly with three other parts — the bottom bracket, the chainring and your pedals — so compatibility matters at every connection point.
What crank arm length should I choose?
Standard MTB crank arms are 170mm or 175mm. Shorter cranks (165mm, 160mm) have become popular for DH and enduro: they provide more ground clearance, reduce pedal strikes on rocks, and allow a slightly lower bottom bracket height without penalty. The power difference between 170mm and 175mm is negligible for most riders, and if you clip pedals frequently on rocky trails, going to 165mm solves it mechanically rather than by changing your pedalling style.
Which spindle interface fits my bottom bracket?
The spindle passes through the bottom bracket and connects the two crank arms. Shimano Hollowtech II uses a 24mm hollow steel spindle integrated into the right (drive-side) crank arm. SRAM DUB uses a 28.99mm alloy spindle. Race Face Cinch uses a 30mm spindle compatible with Race Face and Easton cranks, and Hope uses a 30mm spindle with their own crank design. The spindle interface determines which bottom bracket you need — these are not interchangeable.
Alloy or carbon cranks?
Alloy cranks (forged 7050 or 7075 aluminium) are strong, stiff and relatively affordable, and Shimano SLX and XT alloy cranks are excellent. Carbon cranks save 50-100g per pair but cost significantly more and can be damaged by rock strikes. For trail and enduro riding alloy is the pragmatic choice; carbon makes more sense on XC race bikes where the cranks are less exposed to rock strikes.
Do I need Boost cranks?
Boost cranks use a 3mm outward chainline offset compared to non-Boost, matching the wider Boost hub spacing (148mm rear, 110mm front) that's now standard on MTBs. Running a non-Boost crankset on a Boost frame shifts the chainline inward and causes poor chain alignment with the outer cassette sprockets. Most modern cranks are Boost-compatible or Boost-specific, and a 3mm chainring spacer or a Boost-specific chainring fixes the chainline without replacing the whole crankset — worth checking before you buy other MTB components to go with it.