DON’T Buy A Used Bike Without Checking THIS, by GCN Tech on YouTube. 17 min 20 s.
- Video length
- 17 min 20 s
- Time to do it
- 20 minutes
- Difficulty
- Easy
- Steps
- 8
What you need
Steps
Spin each wheel and watch the rim as it passes the brake pads. A rim that wobbles side to side means the wheel is out of true. Check the tyres for cuts, cracks and worn tread, and squeeze them to feel the pressure.
Look over the chainrings, cassette and derailleur pulleys for hooked, sharp or broken teeth. A drivetrain with pointed teeth is worn out and will need replacing soon.
Measure chain wear with a chain checker or a ruler over 12 inches of chain. If the checker drops in easily or the pins sit past the 1/16 inch mark, the chain is stretched and the cassette is likely worn too.
Shift through every gear while turning the pedals. The chain should move cleanly up and down the cassette. Look at the derailleur hanger from behind to check it is straight and not bent.
Inspect the frame tubes, welds and joints for cracks, dents and deep scratches, especially under the bottom bracket and around the head tube. Check the seatpost moves freely and is not seized in the frame.
Squeeze the brake levers hard and check the pads have material left and hit the rim or disc squarely. Test the brakes by rolling the bike and stopping. Cables should pull smoothly without fraying.
Hold the front brake and rock the bike forward and back to feel for play in the headset. Turn the bars side to side to check they move freely. Check the stem bolts and bar tape for damage.
Add up the cost of any worn parts, such as chain, cassette, tyres and brake pads. Use that figure to negotiate the price or walk away if the frame or wheels are damaged.
Tips and common mistakes
Bring a chain checker with you, since a stretched chain is the most common hidden cost on a used bike.
Never buy a bike with a cracked frame, even a small one, because repairs are rarely worth it.
Check the frame number and ask for proof of ownership to avoid buying a stolen bike.
Pump the tyres to the pressure on the sidewall before your test ride so handling feels normal.
Questions
How do I check chain wear without a tool?
Lay a ruler along 12 inches of chain and line up the zero mark with a pin. If the pin at the 12 inch mark sits more than 1/16 inch past the mark, the chain is worn.
What is the biggest red flag on a used bike?
Cracks or dents in the frame are the worst sign, because they make the bike unsafe. Worn chains and cassettes are common but easy to price into the deal.
Should I test ride a used bike before buying?
Yes, always ride it if you can. A short ride shows up gear, brake and handling problems that are hard to spot when the bike is standing still.
This guide was drafted from the video's details and general task knowledge. It has not been checked against the full video. Check the video and relevant product instructions before following a procedure. Report a correction.
