Tyres account for a large share of MOT failures every year, and the reasons are consistent. Almost all of them can be spotted in a few minutes beforehand, which turns a likely fail into a simple pre-test fix.
The usual culprits
Most tyre failures come down to a handful of faults:
- Tread below 1.6mm: the single most common, and often on just one edge where wear is uneven
- Damage: cuts, lumps, bulges or cracks in the tread or sidewall
- Exposed cord or ply: where the rubber has worn or been damaged through to the structure beneath, an automatic fail
- Wrong size or rating: a tyre that does not match what the vehicle requires
- Mixed constructions: radial and cross-ply tyres on the same axle, which is not allowed
- Incorrect fitment: a directional or asymmetric tyre fitted the wrong way round
- TPMS fault: a tyre pressure warning light on a car from 2012 onward
- Valve damage or a tyre not correctly seated
The ones drivers miss
A few of these slip past a casual glance. Uneven wear is the big one: a tyre can look fine across most of its face while the inner edge has worn below the limit, which is common on cars that need an alignment, and increasingly on heavier electric cars where the inner edge wears first. Turning the wheel to full lock to inspect the inner shoulder catches it.
A TPMS warning light is another. It is easy to live with a dashboard light for weeks, but on a car from 2012 it means a straight fail, so it is worth resolving before the test rather than discovering it on the day.
Catching them beforehand
A short pre-MOT check covers the lot:
- Check tread at several points across each tyre, including both edges
- Look over the tread and sidewalls for cuts, bulges or anything embedded
- Make sure no tyre warning light is showing
- Confirm pressures are at the recommended figures
None of this needs tools beyond a tread gauge or a 20p coin, and it is far cheaper than a failed test, a retest, and a tyre bought in a hurry, far better to spot a worn one early and replace it in good time, ordering the new one online from a tyre shop like Tyres.co.uk.
Prepare without disguising a defect
Measure tread and look for visible damage, but do not attempt to conceal cracking or cuts with dressing. Check pressures and resolve monitoring warnings properly rather than resetting them solely for the appointment. Tell the garage about rapid pressure loss or a recent impact. An MOT is an inspection at a point in time; it is not a full dismantled tyre examination or a replacement for routine maintenance afterwards.
Common questions
What is the most common tyre MOT failure?+
Tread below the 1.6mm legal minimum is the most common, often on one edge where wear is uneven. Damage such as cuts, bulges and exposed cord is the next most frequent reason a tyre fails.
Will a tyre warning light fail an MOT?+
On cars first used from 2012, a tyre pressure monitoring warning light that stays on means the system is registering a fault, and that is a major MOT failure. It should be investigated before the test.
Can the wrong tyre size fail an MOT?+
Yes. A tyre that is the wrong size or an unsuitable rating for the vehicle is a failure, as is mixing radial and cross-ply tyres on the same axle or fitting a directional or asymmetric tyre the wrong way round.
How do I avoid a tyre MOT failure?+
Check each tyre's tread at several points, look over the sidewalls and tread for damage, make sure no tyre warning light is on, and confirm pressures are correct. Catching these beforehand avoids a fail and a retest.