Buying a used bike is one of the best ways to get significantly more bike for your money. It’s also where many people get burned — buying something that needs expensive repairs, was stolen, or simply doesn’t fit. This checklist reduces those risks substantially.
Before You Meet the Seller
Research the bike model and what it should sell for. Use completed eBay listings (not active ones) to see what similar bikes actually sell for. If the asking price is significantly below market rate, ask why before going to view it.
Check the bike against the Bike Register or a similar stolen bike database. In the UK, BikeRegister.com lets you search by frame number. In the US, BikeIndex.org does the same. A stolen bike can be recovered by its owner even after you’ve paid for it — you get no refund, just the loss.
Ask the seller for the frame number and check it before traveling. If they won’t provide it, don’t go.
Checking the Frame
Look for cracks, particularly around welds, the head tube, bottom bracket shell, and dropout (where the wheel axle sits). A crack in a frame is potentially dangerous and rarely worth repairing economically.
Check for bent tubes. Sight along the top tube and down tube from the front — they should be straight. Look at the rear triangle: the seatstays and chainstays should be symmetric. A frame that’s been in a hard collision may be bent in ways that aren’t immediately obvious but affect handling.
For carbon frames: press firmly along all the tubes feeling for soft spots or crackling sounds. These indicate delamination. Carbon bikes that have been dropped or crashed can have internal damage that’s invisible externally.
Checking the Wheels
Spin each wheel while watching the rim pass a fixed point. More than 2-3mm of lateral wobble indicates a wheel that needs truing. A wheel with broken spokes (check each one — it should be taut, not loose or broken) will be expensive to rebuild.
Look at the brake track on each rim. If it’s concave (worn hollow), the rim is nearing the end of its life. Some rims have wear indicators — a groove that disappears when the rim is worn through. A worn rim needs replacing, which costs $40-100 per wheel.
Checking the Drivetrain
A chain wear indicator tool is the reliable way to check chain wear; eyeballing it is unreliable. If you don’t have one, try to lift the chain off the front chainring — if it pulls away more than 5mm, it’s worn. A worn chain may have worn the cassette and chainring with it, making a full drivetrain replacement necessary ($80-200).
Check gear shifting: run through all gears front and rear. Hesitation, slipping, or refusal to shift to certain gears indicates cable, derailleur, or cassette issues. Some of these are cheap fixes (cables); some are expensive (bent derailleur hanger, worn cassette).
Checking the Brakes
Squeeze each brake firmly. The lever should not reach the handlebar, and the bike should stop promptly. Spongy hydraulic brakes may need bleeding. Cable brakes that feel weak usually need new cables and pads — cheap fixes.
Check the brake pads for wear. On rim brakes, the wear indicator groove should still be visible. On disc brakes, the pad should have at least 1.5mm of material remaining.
Test Ride
Always test ride. The bike should track straight (let go of the bars briefly on a safe surface), shift through all gears smoothly under load (not just while stationary), and brake effectively. Any shimmy, vibration, or handling oddness warrants investigation before buying.
The Final Check: Does It Fit?
The correct frame size is the purchase criterion that most people skip. A bike that doesn’t fit is uncomfortable at best and damaging at worst. Check standover height (straddle the bike — there should be 1-2 inches of clearance for a road bike), reach, and saddle height range. A bike that’s too large or too small isn’t worth buying regardless of its mechanical condition.