PRACTICAL GUIDE · 6 MIN READ
What size second-hand bike should I buy?
The photographs, measurements and chart checks to collect before travelling to see a used bike.
Everyday Bike Fit product guide · updated 2026-09-22 · Independent fitter review pending.
Match the bike’s full model, frame label and wheel option to its own sizing chart before buying. The seller’s height, purchase year or description of “medium” is not enough to establish your size.
Sign in to open frame sizing and save your shortlist.
Ask for a few useful photographs
Request a full side view, close-ups of the model wording and frame-size label, the wheel-size marking, and the seatpost and handlebar setup. Ask whether the stem, bars, seatpost or fork have been changed.
Photos help identify a listing and prepare questions. They cannot establish the bike’s structural condition or prove that its brakes, frame and components are safe. Arrange a mechanical inspection when you need one.
Separate purchase year from model year
A bike bought in one year may belong to an earlier model year. Keep a receipt date as a purchase date unless other evidence establishes the model year. Component upgrades or replacement decals can also make photographs misleading.
Find the exact archived listing, retaining its model number and suffix. If the generation remains uncertain, keep the chart unconfirmed. Year unknown is an acceptable starting state.
Match your measurements to the evidence available
Measure height and inside leg barefoot, then open the model guide. A published body-range chart can suggest candidates. An entry listing only S, M and L cannot do that; it needs the exact manufacturer range or individual sizing advice.
If two sizes overlap, retain both. Do not borrow a chart from today’s version of the same model or a different wheel option just because it looks similar.
Use the inspection to resolve the remaining questions
Check the physical size label against the advert. Confirm mounting and brake access, inspect the component adjustment limits, and compare the installed parts with the source specification. Try the bike only when it is safe and the seller permits it.
Record parts that would need changing before you decide whether the bike is a good purchase. A low price does not compensate for a position that cannot be achieved safely within the frame and component limits.