Buying a used bicycle: the checklist for frame, size and wear

A good used bicycle is one of the best deals there is: quality bikes last, and the steepest depreciation has already been paid by the first owner. Three things decide whether the purchase succeeds: the right size, a healthy frame and an honest look at the wear parts.

Size first – it is non-negotiable

The best bargain is useless if the bike does not fit. Before enquiring, check the frame size (in cm or S/M/L) and compare it with your inseam. Rule of thumb: inseam × 0.66 for road bikes, × 0.59 for mountain bikes gives the frame height in centimetres. Seatpost and stem allow fine-tuning, not size correction.

Frame and fork: the knockout criteria

• ·Aluminium frames: check for dents and cracks, especially at the welds of head tube and bottom bracket.
• ·Carbon: no deep scratches, no soft spots, no creaking under a load test. After a crash, carbon can be invisibly damaged – ask explicitly about crashes and document the answer in the chat.
• ·Fresh paint touch-ups on load-bearing areas are a warning sign of concealed damage.
• ·Spin the wheels freely: lateral and vertical wobble, loose spokes, brake tracks on rim-brake wheels.

Think of wear parts in francs

None of this is a deal-breaker – but all of it belongs in the price calculation:

• ·Chain and cassette: 60 to 150 francs including fitting
• ·Brake pads (and rotors on disc brakes): 40 to 150 francs
• ·Tyres: 50 to 120 francs per pair
• ·Cables and housings or brake fluid: 50 to 100 francs
• ·Full service at the mechanic: 100 to 250 francs

The test ride

• ·Shift through all gears under load – skipping or rattling means adjustment work or wear.
• ·Test each brake firmly on its own, including from some speed.
• ·Let the bike roll with a light grip: it should track straight and true.
• ·Quick bearing check: rock the handlebars with the front brake pulled (headset), push the crank sideways (bottom bracket), tilt the wheels sideways (hubs).

Provenance, price, closing

As with e-bikes: note the frame number, ask for the purchase receipt and walk away from suspiciously low prices without proof of origin – stolen bikes are the number-one risk in the second-hand market.

For the price, compare three to five similar listings and deduct the concrete wear costs. Well-kept brand bikes with service receipts rightly fetch more; when selling, it pays to publish exactly those receipts in the listing.