Updated May 2026
What is the MOT tyre tread requirement in the UK?
The UK MOT tyre tread minimum is 1.6mm across the centre 75% of the tread, around the full circumference of every tyre, on all four wheels. Below that and the tyre fails. At MOT Checkup we see tyres flagged as the second most common fail item — a free MOT check shows last year's tyre advisories at a glance.
TL;DR
- 1.6mm minimum tread depth
- Measured across the centre 75% of the tread width
- Around the full circumference — uneven wear can fail
- Applies to all four tyres independently
- Pass-with-advisory typically logged at ~3mm or below
The four checks the tester runs
- Tread depth. Measured at multiple points across the centre 75%. Below 1.6mm anywhere in that zone = fail.
- Tread pattern continuity. Treads must run around the full circumference; a worn-flat patch fails.
- Sidewall and casing. Bulges, cuts, or exposed cords are an automatic fail.
- Inflation and matching. Significant underinflation, or mismatched tyre types on the same axle, fail the test.
What the result categories mean
| Tread depth | MOT outcome | Action |
|---|---|---|
| Above 3mm | Pass, no comment | Drive on |
| ~1.6mm – 3mm | Pass with advisory | Plan replacement |
| Below 1.6mm in centre 75% | Major defect — fail | Replace before driving |
| Cords showing / sidewall split | Dangerous defect — fail | Do not drive on public road |
The 2018 categorisation introduced minor / major / dangerous defects — see advisory vs fail vs dangerous for the full breakdown.
Why the centre 75% rule exists
The centre 75% is where tyres do most of their work — channelling water away from the contact patch and providing grip in the dry. The shoulders matter for cornering, but they wear at a different rate from the centre, and the rule recognises that. A tyre with good shoulders but worn-out centre tread is dangerous because aquaplaning starts at low speeds.
The 20p test
A 20p coin gives a free at-home check. Slot the coin into the main tread groove. If you can see the outer band of the coin, the tread is below ~3mm — time to think about replacements. If the band disappears completely, you're still legal but check at multiple points before assuming the whole tyre is fine. See our tyre safety guide for the full method.
What about the spare?
The spare wheel is not part of the MOT. The tester only inspects the tyres in use on the road. That said, it's worth checking your own — many cars now ship with a space-saver or repair kit rather than a full-size spare, and a flat or perished spare is useless.