The tread is below the UK legal minimum of 1.6mm, measured across the central three-quarters of the tread width and around the entire circumference. It's a measured, black-and-white item — there's no interpretation involved.
Wording as it commonly appears on an MOT certificate: “Tyre tread depth below the legal limit of 1.6mm”.
What does it mean?
The tread is below the UK legal minimum of 1.6mm, measured across the central three-quarters of the tread width and around the entire circumference. It's a measured, black-and-white item — there's no interpretation involved.
How serious is it?
Usually recorded as: Major. The tester assesses the actual vehicle on the day, so your certificate is what counts.
What normally causes it?
- Normal wear
- Under-inflation, which wears the shoulders and leaves the middle looking fine
- Over-inflation, which does the opposite and wears the centre band
- Wheel alignment out, which wears one edge in a distinctive feathered pattern
- A worn damper or suspension component causing scalloped, patchy wear
What a mechanic would check
Depth gauge in several places across and around the tyre, not just the one spot. Then I'd look at the wear pattern, because that's the useful part — even wear is just mileage, but edge wear or feathering tells you the geometry needs setting before the new tyres go the same way.
What might need replacing
- One or more tyres
- A four-wheel alignment if the wear pattern is uneven
- Suspension attention if the wear is scalloped
Can you still drive it?
Below 1.6mm you're not only failing the MOT, you're breaking the law every time you drive — and the penalty applies per tyre. Wet grip falls off sharply below about 3mm long before you reach the limit, so don't let it get here.
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This is general guidance from a UK mechanic, not a substitute for a physical inspection. Only the tester who inspected your vehicle can confirm what was recorded and why.