Quick answer
For most cars in the UK, the legal minimum tread depth is 1.6mm across the central three-quarters of the tyre around the full circumference.
If tread is below that level, or the tyre has dangerous damage, the vehicle can fail its MOT.
When tyres can fail an MOT
- !Tread depth below legal minimum.
- !Exposed cords or canvas.
- !Bulges, cuts or structural damage.
- !Severe uneven wear.
- !Incorrect tyre size or unsafe fitment.
- !Tyres fouling bodywork or suspension.
Legal tread depth explained
1.6mm minimum
Applies to most passenger cars on UK roads.
Across main contact area
Measured across the central three-quarters of the tread.
Whole circumference
The requirement applies around the tyre, not one small section only.
Replace earlier if possible
Grip in wet weather reduces before tyres reach the legal limit.
Simple tyre checks before MOT
- 1Check tread with a gauge or wear indicators.
- 2Inspect inner and outer edges for uneven wear.
- 3Look for cuts, cracks or bulges.
- 4Check tyre pressures when cold.
- 5Make sure matching sizes are fitted correctly.
- 6Replace borderline tyres before the test.
Why tyres wear unevenly
Poor wheel alignment
Common cause of inner or outer edge wear.
Incorrect pressure
Under or over-inflation changes wear pattern.
Suspension wear
Worn bushes or joints can affect tyre contact.
Driving style
Hard cornering and braking increase wear.
Wheel balance issues
Can create vibration and patchy wear.
Neglected rotation
Some vehicles benefit from regular tyre rotation.
Will tyres close to 1.6mm pass?
Possibly, but if tyres are very close to the limit many drivers replace them before MOT to avoid risk, improve grip and prevent a near-future failure.
Can one tyre fail the whole MOT?
Yes. A single tyre below the legal standard can result in failure.
Related MOT and tyre guides
Frequently asked questions
Can 2mm tyres pass MOT?
Usually yes if condition is otherwise safe, but replacement may be sensible soon.
Do spare tyres count?
Normally the tyres fitted to the vehicle are the main concern.
Can sidewall damage fail MOT?
Yes, especially cuts, bulges or exposed cords.
Can tyres get an advisory?
Yes, for wear approaching limits or age-related concerns.
Should I replace tyres before MOT?
Often wise if close to limits or visibly damaged.
Are tyres a common MOT fail?
Yes, tyres are one of the most frequent problem areas.