Checklist: What to Check Before Buying a Used Bike

Buying a used bike involves two separate checks, and most guides only cover the mechanical one. A bike can be in perfect condition and still be stolen, in which case it is not yours, you will not be compensated, and it can be taken back.

Do the provenance check first. It is quicker and it is the one that can cost you everything.

Part one: is it actually theirs to sell

1. Find the frame number. It is stamped into the frame, usually underneath the bottom bracket where the pedal cranks meet, sometimes on the head tube or the rear dropouts. Turn the bike upside down and look. A seller who will not let you find the frame number has ended the conversation for you.

2. Check it against BikeRegister. BikeRegister is the UK's national cycle database, used by police forces, and it has a free stolen-bike check. Enter the frame number before you hand over money. A hit means walk away and report it. No record is not proof the bike is clean, because not every owner registers, but it is a meaningful check that takes a minute.

3. Look for a tampered number. Filed, ground, painted over or unusually shallow stamping is a serious warning sign. So is a frame number that does not match the bike's apparent age or model.

4. Ask for the original receipt or proof of purchase. Plenty of genuine sellers no longer have one, so its absence is not damning. But a seller who has the receipt, the original bike shop, the registration and the story that matches is a very different proposition from one who has none of it.

5. Ask questions a real owner can answer. What size is the frame, what did you change on it, where did you buy it, why are you selling. Someone who has ridden a bike for two years answers these without pausing. Someone who acquired it last night does not.

6. Be suspicious of the price. A £1,200 bike for £250 is not a bargain, it is an explanation. Stolen bikes are priced to move quickly.

Part two: is the bike any good

Frame first, because everything else is replaceable and a cracked frame is not.

• Check the whole frame for cracks, dents and ripples, especially around the welds, the head tube and under the bottom bracket.
• On carbon frames, press firmly along the tubes listening for creaking, and look for spider-web cracking in the paint. Carbon damage can be invisible and structural, so if in doubt, walk.
• Check for rust at the seat post and inside the frame where possible.

Then the wheels and drivetrain.

• Lift each wheel and spin it. It should run true, without wobbling side to side, and without rubbing the brake.
• Grab the wheel at the top and rock it sideways. Play means worn hub bearings.
• Look at the teeth on the chainrings and rear cassette. Sharp, hooked or shark-fin shaped teeth mean a worn drivetrain, which is a real cost to replace.
• Lift the rear wheel and run through every gear. It should shift cleanly in both directions.

Then the contact points and controls.

• Squeeze both brakes hard. They should bite well before the lever reaches the bar. Check pad thickness and, on disc brakes, look for scoring on the rotors.
• Hold the front brake and rock the bike forwards and backwards. A knock means a loose or worn headset.
• Grab the cranks and push side to side. Movement means bottom bracket wear.
• Check the tyres for cracking in the sidewalls, which means age rather than use.

Then ride it, if the seller allows and it is safe to do so. Leave something as security if asked. Listen for creaks, check it tracks straight hands-off on a quiet stretch, and try every gear again under load.

Do not skip these

• Check the size is right for you. The cheapest bike in the world is worthless if the frame is two sizes too big. Manufacturers publish size guides by height.
• Take photographs of the frame number and the bike before you pay, whatever happens next.
• Meet somewhere sensible. A police safe exchange zone if your force runs one, otherwise a busy public place in daylight. See where to meet a buyer safely.
• Register it as yours on BikeRegister as soon as you buy it, and take your own photographs. If it is ever stolen, this is what gets it back.

The gap this checklist leaves

You can do every check above and still not know who sold it to you. If the bike turns out to be stolen despite a clean database check, "I bought it from a bloke called Chris off Marketplace" gives the police nothing to work with and gives you no route to recover your money.

Chainr covers that half. Both buyer and seller verify their real identity with a government ID and face check, you record the item and its frame number, and you seal the handover in person with a six digit code. You both keep a timestamped certificate showing the item, the price and both verified names. If the bike is ever questioned, you can show exactly who you bought it from and when.

Related: where to meet a buyer safely, is Facebook Marketplace safe, the eight most common private sale scams.