Wheel Issues That Can Cause an MOT Fail

Worn tyres, cracked or bent wheels, loose fixings, and some other faults can cause an MOT fail. This guide explains wheel issues that can cause an MOT fail, and helps you tell cosmetic marks from faults that need action before the test. It covers normal passenger cars in England, Scotland and Wales; Northern Ireland uses separate guidance.

Which wheel and tyre issues can cause an MOT fail?

Wheel-related MOT failures include low tread, tyre damage, the wrong tyre fit, serious rim damage, and loose wheels. Testers check tyre condition, size, type, tread depth, wheel condition, and security. Steering and suspension are checked too, so the fault may be more than the tyre alone.

The difference between a fail and a warning matters. Major and dangerous defects mean a failed MOT, while minor defects and advisories do not always stop a pass. Even so, an advisory needs attention. Passing the test is not a reason to ignore a growing problem.

Tyre defects that need attention before testing

1. Tread below the legal minimum

For normal cars, tyres need at least 1.6mm of tread across the middle three-quarters of the tread width and all the way around the tyre. Checking one easy spot is not enough. Check several points, because a tyre may have enough tread in one area and less elsewhere.

A tread-depth gauge gives you a measurement rather than a guess. The 20p coin check is useful for a first look: place the coin in the main grooves and look for its raised outer edge. If that edge is still visible, get a proper check instead of assuming the tyre will pass. Repeat the check at several points on every tyre. 

2. Bulges, cuts and exposed cords

Tyre issues are not limited to worn tread. Bulges from internal damage, tread separation, and exposed cords are serious defects, even when the tread looks deep. Check the sidewalls as well as the part that touches the road; damage on the inside can be easy to miss.

Do not judge a cut by its length alone. Its depth and whether it reaches the internal reinforcement also matter. If you find a bulge, exposed cords, or a deep cut, get a professional check before driving on. Arrange help if the tyre seems unsafe. A home check should spot concerns, not turn into an attempt to pull damaged rubber apart. 

3. Incorrect sizes and unsuitable fitment

Different tyre sizes or types on the same axle can cause a failure. But that does not mean all four tyres must always match: some vehicles have maker-approved differences between the front and rear. Check the vehicle spec rather than copying the tyre already fitted.

When you replace tyres, ask the fitter to confirm the right size and load and speed ratings for your car. Mention any aftermarket wheels or earlier changes to the tyre spec. This is about fit, not just whether the tyre physically fits the rim.

Wheel damage is different from cosmetic scuffing

A wheel fracture or welding fault is classed as dangerous. Heavy distortion can also cause failure, while a loose or missing wheel nut, bolt, or stud is a major defect; more than one on a wheel is dangerous. These are strength and safety issues, not appearance issues. (gov.uk)

For car wheel damage, the key point is the difference between a surface mark and a defect that affects the wheel's strength. Ask a technician to check suspected cracks or bends rather than choosing cosmetic repair first. Tell them about any recent impact and whether you have seen pressure loss or vibration. These details help guide the wheel inspection, but they do not prove the fault on their own. (gov.uk)

Use these notes when you describe the problem to a garage:

• A visible line or split: note where it is and ask if it is a structural crack.
• A clearly bent rim: ask for a check of the wheel and tyre fit, not just the finish.
• Missing fixings: treat wheel security as urgent rather than waiting for the MOT appointment.

Tyre pressure and dashboard warnings need separate checks

A clearly under-inflated tyre is a minor MOT defect, not always a failure. A faulty tyre pressure monitoring system, when fitted and checked, is a major defect. A warning light alone does not prove the system is faulty, so the cause needs a proper check. (gov.uk)

For maintenance, use the vehicle maker's recommended pressures for the load being carried. You will usually find these in the handbook or on a label inside the driver's door or fuel flap. No single correct pressure applies to every car, and the front and rear settings may differ. (nationalhighways.co.uk)

Check pressures when the tyres are cold, and follow the vehicle's instructions. Do not rely on how they look or wait for a warning light: a gauge is the practical way to check. If a tyre keeps losing pressure, ask a professional to find the leak instead of just topping it up. (nhtsa.gov)

Your pre-MOT checklist for wheels and tyres

Use this MOT checklist before the appointment, and leave time to deal with concerns rather than finding them on test day. It is only a prep aid, not a replacement for a professional inspection or normal tyre maintenance. The MOT itself is not a full service or a full check of general mechanical condition.

1. Check every road tyre's tread. Measure several points across the required middle band and around the tyre. Record the lowest readings, not the best-looking area.
2. Look for damage. Check visible tread and sidewalls for cuts, bulges, and exposed reinforcement. Ask a technician to inspect places you cannot see well. 
3. Measure pressures. Use a gauge and the maker's settings for your load. Note any tyre that needs repeated top-ups so you can explain the pattern.
4. Inspect visible wheels and fixings. Look for cracks, bends, or missing nuts and bolts. Do not assume a wheel is secure just because the car still drives. 
5. Report driving symptoms. Mention uneven wear, pulling, vibration, or dashboard warnings. Say when each one happens rather than asking for one repair without a diagnosis. 
6. Check the spare for your own use. Spare wheels and tyres are not checked in the car MOT, but checking them is still sensible maintenance.

Make wheel safety a year-round habit

The best wheel inspection is one that leads to action. Keep checking tread, pressures, and damage between tests, and deal with handling changes quickly. Vehicle safety remains your responsibility even when the car has a current MOT certificate.

If the car fails, read the defect classes before deciding whether it can be driven. You cannot drive with a dangerous defect. Taking it away after failure needs a still-valid MOT and no dangerous defects, and the car must remain roadworthy. If you are in doubt, arrange repairs or recovery instead of assuming the trip home is allowed.