Components

Buying Used MTB Components

Components are where used buying makes the most sense. A Shimano XT derailleur with a season on it shifts identically to a new one, and drivetrain parts are consumables anyway — chains, cassettes and brake pads wear out regardless of whether they started life on your bike or someone else's. Buying used lets you run higher-spec parts for the same budget.

What to Look For

Wear varies massively by component type. Drivetrain parts (chain, cassette, chainring) have a finite lifespan and a worn chain will accelerate wear on everything it touches — check chain stretch if buying used. Brakes are more durable — brake calipers and levers last years, while pads and rotors are cheap consumables. Cockpit parts (bars, stems, grips) are essentially buy-once items that last until you crash or change preferences.

Compatibility

The main trap with used MTB components is compatibility between generations and brands. Shimano 12-speed and SRAM 12-speed are not interchangeable — different pull ratios, different freehub bodies, different chain widths. Within a brand, things are generally backwards-compatible within the same speed count. If you're building up a drivetrain, stick to one brand and one speed for the shifter, derailleur, cassette and chain.

Condition Grades

Cosmetic damage on components rarely matters — scratched anodising on a stem doesn't affect clamping force. Structural damage is a different story. Check aluminium parts for cracks around bolt holes and high-stress areas. Carbon bars and seatposts should have no visible damage, chips or deep scratches — carbon doesn't bend, it snaps, and failure is sudden. When in doubt, don't buy used carbon cockpit parts.