Used bike checklist

Ask for the frame number near the bottom bracket, rear dropout or in the maker's documents. Search the number, check local stolen-bike groups, archived listings and registries relevant to the bike's country. No match does not prove clean ownership, so proof of purchase or a sale agreement still matters.

Compare completed auctions, archived listings and current offers in the same size. A price far below market is not automatic proof of theft, but it does require stronger origin, frame and service checks.

Ask for close photos of the serial number, front frame junctions, underside of the lower frame tube, bottom bracket area, fork upper tubes, cassette near the spokes, hooked teeth on used sprockets and derailleur mount.

A useful answer has a date, scope and place: fork lower service, chain replacement, brake service, suspension bearings. 'It was serviced recently' without detail counts as no history.

Choose open space, enough time and permission for a test ride. A dark garage, rushed meeting or refusal to let you inspect the frame is a reason to reschedule or leave.

A coin tap is only a warning signal, not a diagnosis. A dull response, soft spot, ripple under paint, spider-web paint cracks after impact or fresh paint in a contact zone means you buy only with independent carbon inspection and repair records.

A hairline crack near a weld, steering area, bottom bracket shell, dropout or shock mount is not cosmetic. A small dent away from stress zones may be a pricing point, but it does not replace a service inspection.

Stone chips are normal, but fresh film exactly over an impact zone should be lifted and checked around the paint edge. On carbon, any suspicion of crushed laminate or separation belongs with a specialist.

Inspect the tube junctions in angled light and turn the bar fully both ways. Uneven gloss, paint cracks, a mark from a hard bar rotation or headset play after adjustment are reasons to leave or get an independent diagnosis.

Hold the rear wheel and move it sideways while touching the suspension joints. Play can mean bearings, bushings or hardware, so without service records you should budget parts and labour.

Cost/takeaway: Often a few hundred PLN equivalent; more if hardware is seized or a linkage part is damaged.

After a fall or transport, the hanger may be slightly bent. Symptoms include difficult indexing, skipping on selected gears and the chain moving toward the spokes. A workshop checks this with an alignment gauge, not by eye alone.

Cost/takeaway: Alignment or replacement is usually modest, but unusual hangers can be hard to source.

Use a gauge, but the threshold depends on the drivetrain. On 11/12-speed systems, 0.5% is often the chain-replacement point; older systems often use 0.75%. At 1.0%, assume the cassette and rings may already be affected.

Modern cassettes use shift ramps and varied tooth profiles. Check against photos of a new cassette, look for hooked loaded edges on favourite sprockets, skipping under load and poor behaviour with a fresh chain.

Cost/takeaway: The cassette can be the biggest drivetrain cost, especially on 12-speed bikes.

Alternating wide and narrow teeth on 1x drivetrains are intentional. Problems are hooked teeth, very thin tips, missing teeth, chain drop and skipping during a hard effort.

Small side play at the pulleys is normal, but sharp teeth, grinding or a weak clutch on an MTB reduces chain control. Also check that the cage is not twisted from impact.

Every click should be distinct and the derailleur should return without delay. Heavy action often points to cable and housing, while empty clicks may mean a worn lever mechanism.

Move the crank sideways and rotate it slowly, ideally with the chain dropped from the ring. Play, grinding or notchy movement means adjustment, bearings or spacer issues.

There is no single number for every brake. Many Shimano instructions call for pad replacement at 0.5 mm of friction material, while SRAM often uses 3 mm for pad plus backing plate. Uneven wear suggests caliper or piston trouble.

Minimum thickness depends on brand and model. Many Shimano rotors list 1.5 mm, while SRAM lists 1.55 mm for 1.85 mm rotors and 1.7 mm for 2.0 mm rotors. Cracked, heavily heat-marked or bent rotors need replacement.

The lever should not touch the handlebar, and the bite point should stay repeatable after several hard stops. Spongy feel, growing lever travel or fluid at the caliper means brake service.

Squeal does not always kill a rotor, but it can point to contaminated or glazed pads. After the test ride, check that the wheel spins freely and the rotor does not rub at one spot.

Ask which fluid the brake requires and when it was last serviced. Mixing fluids or using the wrong procedure can damage seals.

Look for scratches you can feel with a fingernail, burrs, discolouration and dry movement. A deep mark where the seal slides usually means expensive service or replacement parts.

A light grease film can be normal, but a wet dirt ring, air noise, knocking or failure to return after compression requires service. Without an invoice, treat the suspension as overdue.

Do not remove the valve core. Attach a shock pump to the Schrader valve and compare settings with the same pump, because reconnecting the pump can change the reading as the hose fills. Sag, full travel, witness marks and service history matter more.

Fox lists full service around 125 hours or yearly as a reference. RockShox commonly splits 50-hour service and fuller 100/200-hour service depending on model. No history means a service cost in your budget.

Cost/takeaway: On a full-suspension bike, often budget fork and shock service after purchase.

Adjusters should have clear positions or a predictable range matching the model. No change between extremes can point to damper trouble.

A small side wobble may only need truing, but cracks at spoke holes, a dented bead, brake contact or tubeless sealing trouble are real costs.

Compare the sound of neighbouring spokes and gently squeeze pairs by hand. One loose spoke is not automatically a free quick fix; it may mean poor tension, a damaged nipple or a tired rim.

Move the wheel sideways and rotate it slowly. Play, grinding or a skipping freehub means bearings, cone adjustment or ratchet service.

The date code helps, but a three-year-old tyre stored cool can be better than a one-year-old tyre left in the sun. Check sidewall cracks, hard rubber, bead cuts and uneven tread wear.

Ask when sealant was added and whether the rim tape was replaced. Air escaping at the valve or spoke holes means opening the wheel, not just pumping it up.

A short parking-lot loop will not reveal load-related issues. You need pavement, bumps, several hard stops and a climb or sprint in a hard gear.

Shift both ways while pedalling firmly, without abusing the bike. Chain skip on one sprocket usually points to drivetrain wear, hanger alignment or setup.

The bike should stop straight, with no bite-point drift and no rotor rub after releasing the lever. After several stops, the lever should not become soft.

Full travel, smooth return and no sinking under body weight. Slow return may be cable or pressure, but sinking under load means cartridge service.

Movement should be smooth, with no metallic end stroke and no knock on fast unloading. After the ride, check dirt rings at the seals and whether the bike used travel sensibly for the terrain.