Used Bike Inspection: 30-Point Checklist UK

Before you go

From the Cyclesite marketplace. The single most common reason a Cyclesite buyer regrets a used purchase is rushing the inspection. Buyers who spend 20 minutes on the bike before paying have an order-of-magnitude lower regret rate than those who agree on price in the first five. The checklist below takes that 20 minutes and turns it into something repeatable.

A used bike inspection is not about catching out the seller. It is about making sure the bike does what you need it to do, that the price reflects condition, and that you are not buying someone else's problem. Most sellers are honest; some are not; many are honest but do not know what is wrong with the bike themselves. Your job is to find out.

Bring the following:

• A torch (or phone torch) for inspecting frame and inside the bottom bracket
• A pair of nitrile gloves (drivetrains are filthy)
• A small screwdriver or Allen key set for lifting cable end caps
• Cash or a payment method ready in case the bike is right (best price comes from a buyer ready to commit)
• A copy of this checklist on your phone

Allow 60-90 minutes for the inspection plus test ride. Sellers who rush you should be a yellow flag.

The frame inspection

Frame condition is everything. A new groupset on a cracked frame is worthless. A clapped-out groupset on a clean frame is a £200 service away from being like new.

Look for cracks at:

• The head tube, both top and bottom
• The down tube where it meets the head tube
• The bottom bracket shell, especially the underside
• The chainstay where it meets the bottom bracket
• The seat tube where it meets the top tube
• The rear dropouts on both sides

Cracks on aluminium are usually obvious as hairline lines following the frame's stress points. Cracks on carbon are harder to spot; look for any change in surface texture, paint bubbling, or "gel-coat" peeling. A magnifying glass helps. If unsure on carbon, a professional carbon-frame inspection costs £30-£50 and is worth it on bikes over £1,500.

Look for crash damage at:

• Both ends of the handlebar (scuffs, gouges)
• The right-hand rear dropout (where the derailleur hanger lives; bent hangers indicate a crash)
• The shifter housings (scuffs from sliding on tarmac)

A bike that has been crashed is not necessarily a bad buy. A frame that has been crashed and is then sold as undamaged is.

Frame size and fit. Stand over the bike. With both feet flat, you should have 2-5cm of standover clearance on a road bike, 5-10cm on a hybrid, 10-15cm on a mountain bike. Sit on the saddle; can you reach the bars without stretching, can you stand up out of the saddle without hitting your knees on the bars? If not, the bike is the wrong size, no matter how good a deal.

Wheels and tyres

Spin each wheel and watch from above. The rim should track within 1-2mm of true. A wobbly wheel needs truing (£15-£30 at a bike shop) or new spokes (£40-£70).

Check for spoke tension. Squeeze pairs of spokes; they should all feel similarly tight. Loose spokes mean a wheel that needs rebuilding (£50-£100) or replacement.

Check the rim for wear. On rim-brake wheels, the braking surface should be flat. Concave wear or a "wear indicator" line at the limit means the rim is end-of-life and needs replacing. On disc-brake wheels, this does not apply.

Tyres. Look at tread depth and sidewall condition. Cracked sidewalls, threadbare tread, or visible casing through the rubber means new tyres needed (£40-£80 for a set). Make sure the tyre fitted is appropriate for the bike's intended use; tour tyres on a road bike are fine, slick road tyres on a gravel bike are not.

Bearings. Lift each wheel off the ground and spin it. The wheel should spin freely for 10+ seconds. Hold the rim and rock it side to side; there should be no play. Grinding, clicking or play means hub bearings need servicing (£20-£40) or replacing (£40-£100).

Drivetrain check

The drivetrain is where most wear hides. Get gloves on.

Chain wear. Use a chain checker (a £5-£10 tool you should own; sellers may have one). Hook one end into the chain; if the other end drops in cleanly at the 0.5 mark, the chain is half worn (still usable). At the 0.75 mark, chain is end-of-life; if it drops in cleanly, the cassette is also probably worn. At the 1.0 mark, chain, cassette and possibly chainrings need replacing (a £150-£300 repair).

Cassette teeth. Look at the most-used cogs (usually middle of the cassette). Worn teeth are shaped like shark fins (asymmetric, hooked) rather than symmetric trapezoids. Worn cassette = chain skip under load.

Chainring teeth. Same shape principle. Look for shark-fin asymmetry on the most-used ring (usually the smaller front ring on a double, or the only ring on a 1x setup).

Shifting test. Lift the rear wheel, turn the cranks, shift through every gear. Each shift should happen within half a crank revolution. Slow shifts, missed shifts or clicking under load means cable, derailleur or hanger adjustment needed (£15-£30) or component replacement (£50-£200).

Derailleur hanger. Sight along the rear derailleur from behind. The cage should be vertical and parallel to the cassette cogs. A bent hanger throws shifting and is the most commonly damaged part on used bikes (£20-£40 for replacement plus fitting).

Brakes

Two systems on the UK market: rim brakes (calipers, V-brakes, cantilever) and disc brakes (mechanical or hydraulic).

Rim brakes. Squeeze each lever; brake should bite within the first third of lever travel. Pads should sit cleanly on the rim braking surface. Pads worn below the indicator line need replacement (£15-£25). Cables should not be frayed or kinked at exit points.

Mechanical disc brakes. Same lever-feel test. Pad to rotor gap should be 0.5-1mm. Pads at metal backing plate are end-of-life (£15-£25 to replace). Rotor should be flat and unscored.

Hydraulic disc brakes. Lever should feel firm and consistent. Spongy or pumping levers means brake bleed needed (£20-£40 per side). Look for fluid leaks at the lever and caliper. Pad wear same as mechanical.

Test under load. Push the bike forward, squeeze the front brake hard. Front wheel should lock up cleanly. Same with rear. Brakes that need a long pull or do not lock are unsafe and need urgent service.

Bearings (other than wheel bearings)

Headset bearings. Hold the front brake on. Push the bike forward and back. There should be no clicking or play at the head tube. Lift the front wheel; the bars should turn freely with no notchiness or grinding.

Bottom bracket bearings. With the bike off the ground, turn the cranks. Should spin freely without grinding. Hold a crank and try to rock it side to side; there should be no play. Worn bottom bracket = £20-£60 service or replacement.

Pedal bearings. Spin each pedal. Should rotate smoothly. Pedal play means the pedal needs replacement (£30-£200 depending on type).

Cables and housings

Look at every cable entry and exit point on the frame. Frayed cables, kinked housings, or cable ends without end caps mean the bike has not been serviced in a while. Cable replacement is a £30-£50 service that restores most shifters and brakes.

Mechanical groupsets older than 5 years often need full cable replacement to feel right. This is normal maintenance, not a fault, but factor £40-£60 into your budget if cables look tired.

The test ride

Always test ride. Sellers who refuse a test ride should be a deal-breaker.

Before riding: Check tyre pressure (the seller should have inflated to a sensible level; if not, ask). Check saddle is at a sensible height for you. Check both brakes work.

On the ride (10-20 minutes):

• Ride straight; the bike should track without pulling left or right
• Brake hard at moderate speed; both brakes should bite cleanly
• Shift through every gear under load (climbing or accelerating)
• Stand up out of the saddle and pedal hard; no creaks, no slipping
• Sit and pedal smoothly; no clicks or grinding from the bottom bracket
• Bunny-hop a small obstacle (kerb, twig); no rattles, no shifts
• Long descent: brakes should not fade

Listen for:

• Creaks at the bottom bracket (loose bottom bracket, dry chain, dry seatpost)
• Clicks at the headset (loose headset bolts)
• Squeaks at the drivetrain (dry chain)
• Rattles from cables (worn cable housings, loose internal routing)

A noisy bike is not necessarily broken, but it usually needs a £40-£70 service to silence.

The paperwork

Before payment:

• Frame number recorded and cross-checked against BikeRegister
• Original purchase receipt or proof of ownership (if seller has it; many do not for older bikes)
• Service history (if seller has it)
• Reason for sale (a coherent reason; "moving house, downsizing, upgraded" all fine; vague answers a yellow flag)
• Lock and any accessories included or specifically excluded

If the seller cannot provide any proof of ownership and the bike is over £500, walk away. Stolen-bike resale is the most common scam. The bike may also be subject to BikeRegister "stolen" flag, in which case selling it on later becomes complicated and the marketplace may refuse the listing.

For Cyclesite listings: every listing on our platform is screened against UK stolen-bike databases at submission. Buying through Cyclesite is significantly safer than buying through general marketplaces because of this check.

Walk-away signs

Specific things that should end the deal:

• Cracked frame, even hairline
• Significant carbon damage
• Bent rear derailleur hanger that has snapped before
• Severely worn cassette and chainrings (a full drivetrain replacement is £200+ on most bikes; that is rarely worth it on a used bike)
• Stuck seatpost (especially aluminium seatpost in a steel frame; this can mean the post is rusted into the frame and the bike is effectively scrap)
• Snapped frame number, ground-off frame number or a frame number that does not match BikeRegister records
• Seller cannot or will not test ride with you watching
• Seller refuses to let you take a photo of the bike before money changes hands
• Price seems too good for the condition

Walking away from a doubtful deal costs you nothing. Buying a problem bike costs hundreds.

The 30-point checklist

Print this and bring it. Check off as you go.