Tyres are one of the most scrutinised areas during your
MOT – and for good reason.
They’re the only point of contact between your car and the road, and if something’s not right, it can significantly compromise your safety.
But can
poor tyre condition really lead to an MOT failure? Yes –
as reported through our MOT test results report, tyre-related issues are among the top three reasons UK vehicles fail their MOT each year.
In this guide, we’ll walk through what’s inspected during an MOT when it comes to tyres, the most common reasons for failure, and what you can do to avoid it.
What Do MOT Testers Check on Your Tyres?
During your MOT, a certified inspector performs a thorough visual and functional inspection of your
vehicle’s tyres.
Here's what they’ll be looking for:
Tread Depth
The
legal minimum tread depth for most cars is 1.6mm across the central three-quarters of the tyre, measured around the full circumference. If even one tyre falls below this, it’s classed as a dangerous defect and will result in an automatic fail.
Tyre Condition
The sidewalls are checked for cuts, bulges, or tears. Any visible structural damage – such as a bulge indicating internal separation – is a red flag and likely to result in failure.
Tyre Type, Size & Structure
MOT testers ensure all tyres are of the correct size and load rating for the vehicle. Additionally, tyres on the same axle must be of compatible structure – for example, two radial-ply tyres should not be mixed with cross-ply tyres on the same axle.
Pressure & TPMS (Tyre Pressure Monitoring System)
On vehicles registered after 1 January 2012, your TPMS must be working properly. A faulty TPMS warning light showing during the test is marked as a major defect. Tyres that are obviously under-inflated may also trigger a minor defect advisory.
Common Tyre Issues That Lead to MOT Failure
If your tyres have any of the following defects at the time of testing, your car is likely to fail its MOT:
1. Tread Below the Legal Limit
This is one of the most common causes of tyre-related MOT failures. Insufficient tread compromises grip, especially in wet weather. Testers use a gauge to measure tread depth, and anything under 1.6mm is a dangerous defect.
Quick tip: Use the
20p coin test. Insert the coin into the tread groove – if you can see the outer rim, your tread may be too low.
2. Cuts, Bulges or Cracks
Tyres with cuts deep enough to expose cords, or bulges caused by internal damage, will result in an immediate fail. These are not just MOT concerns – they’re serious safety risks.
3. Wrong Tyres for the Vehicle
If the tyres don’t meet your vehicle’s required size, speed rating or load index, that’s a major defect. This includes mixing mismatched structures on the same axle (e.g. radial with cross-ply).
4. Incorrectly Fitted Tyres
Tyres mounted against the directional arrow or with asymmetric sidewalls fitted incorrectly (‘outside’ on the inside) won’t necessarily result in a fail, but the tester may advise you to correct it.
5. TPMS Malfunction
If your
TPMS light is on due to a malfunction, and your vehicle was registered from 2012 onwards, you’ll fail your MOT with a major defect. A low-pressure warning alone may result in an advisory, but not a fail.
How to Avoid an MOT Fail Because of Your Tyres
Avoiding a tyre-related MOT failure comes down to regular checks, maintenance, and knowing what to look out for.
Do a Pre-MOT Tyre Check
Before your test, inspect all four tyres (and the
spare tyre, if fitted) for:
- Tread depth: Use a 20p coin or a tread depth gauge.
- Sidewall damage: Look for bulges, tears, cracks or foreign objects.
- Even wear: Excess wear on one edge may indicate wheel misalignment.
- Inflation: Check tyre pressures against the manufacturer’s recommendations – found in the car manual or on the fuel flap.
- Age: While not all vehicles are tested for tyre age, tyres over 10 years old on certain vehicles (like minibuses) can result in a fail.
Choose Quality Replacements
If your tyres are worn or damaged, replace them before the test. Cheap part-worn tyres can be tempting, but they have poor wear history and may not meet legal standards, being a risk to not just you, but others.
Stick to reputable, preferably premium tyre brands for the highest quality tyre models.
Keep Your TPMS in Working Order
If your TPMS warning light is on, it may just need a reset – especially after a tyre change. If not, it might require sensor or battery replacement. Ask your garage to inspect it before the MOT.
Advisory Notes vs MOT Fails: Know the Difference
Tyres don’t always lead to an MOT fail. Sometimes, they’ll trigger an advisory, meaning they’re close to the limit or showing signs of concern but not yet illegal.
Common tyre advisories include:
- Tread depth approaching 1.6mm
- Minor cracks or perishing
- Uneven wear patterns
- Surface cuts that don’t expose cords
While these may not fail the MOT test, they signal future issues – and may cost you next time around if ignored.
Tyres and MOT Failure: Final Thoughts
Tyres are not just a tick box on your MOT – they’re critical to your safety.
With regular maintenance and a keen eye, you can stay compliant with the law and avoid a costly fail.
Whether it’s tread depth, sidewall condition or a TPMS warning light, don't leave tyre checks until MOT day.
The sooner you spot a problem, the easier – and cheaper – it’ll be to fix.
FAQs:
Can a tyre fail an MOT just because of its age?
For most standard cars, tyre age alone isn't a direct MOT fail point — the tester is looking at condition and tread rather than the date code. However, on certain vehicles such as minibuses, tyres over 10 years old are an automatic failure. Even on regular cars, old tyres are worth replacing regardless, as rubber degrades and cracks over time even when tread depth looks fine.
Will a slow puncture or flat tyre fail an MOT?
A noticeably flat or severely underinflated tyre is likely to be flagged, and the test may not proceed at all if the tyre can't safely support the vehicle during inspection. A slow puncture that hasn't visibly deflated the tyre may only result in an advisory, but it's worth getting it sorted beforehand — turning up with a flat tyre wastes the appointment and you'll still be charged.
Can part-worn tyres fail an MOT?
They can pass an MOT if they meet the legal minimum tread depth and show no signs of damage. However, part-worn tyres are often closer to the limit than you might think, and poorly sourced ones can have hidden damage from their previous use. If you've fitted part-worns recently, it's worth measuring the tread carefully before your test rather than assuming they're fine.
Does uneven tyre wear cause an MOT failure?
Not directly — but if uneven wear has brought any part of the tread below 1.6mm, that's a fail. Heavy wear on one edge is also a sign of misalignment or suspension issues, which the tester may pick up on separately. If your tyres are wearing unevenly, it's worth getting your tracking checked before the MOT rather than just replacing the tyres.
