How to Check Your Tyres Before an MOT

Your tyres are the only point of contact your vehicle has with the road, making them one of the most critical safety components on your car. Unsurprisingly, tyre defects account for roughly 10% of all MOT failures in the UK.

Failing an MOT due to poor tyres is entirely preventable. By performing a simple inspection at home, you can identify issues early, purchase replacement tyres at a competitive price online, and avoid paying premium garage prices on the day of your test.

1. Understand the Legal Minimum Tread Depth

The law in the UK states that car tyres must have a minimum tread depth of 1.6mm across the central three-quarters of the tyre, around its entire circumference.

While 1.6mm is the legal limit, most motoring organisations strongly recommend replacing tyres when they reach 3mm, as braking distances in the wet increase dramatically below this point.

2. The 20p Coin Test

If you don't have a professional tread depth gauge, the 20p coin test is a quick and easy alternative:

• Take a 20p coin and insert it into the main tread grooves of your tyre.
• Look at the coin side-on. If the outer band of the 20p coin is completely hidden by the tyre rubber, your tread is above the legal limit.
• If you can see any part of the outer band of the coin, your tyre tread may be below 1.6mm, and you should have it checked by a professional immediately.
• Remember to check the tread at multiple points across the width of the tyre and around its circumference, as tyres can wear unevenly.

3. Inspect for General Damage

An MOT tester will inspect the entire surface of the tyre, including the sidewalls, which are often overlooked by drivers. You need to check for:

• Cuts and Tears: Any cut deep enough to expose the ply or cords of the tyre is an instant failure.
• Bulges or Lumps: A bulge on the sidewall indicates structural failure within the tyre carcass, usually caused by hitting a pothole or kerb. The tyre is unsafe and will fail the MOT.
• Embedded Objects: Look for nails, screws, or glass embedded in the tread. Even if the tyre isn't losing pressure rapidly, an embedded object can lead to a slow puncture and may result in an MOT advisory or fail depending on severity.

4. Check for Uneven Wear

If the inside or outside edge of your tyre is significantly more worn than the centre, your car's wheel alignment (tracking) is likely out. Uneven wear can quickly cause a tyre to drop below the legal limit on one edge, even if the rest of the tyre looks fine. If you notice uneven wear, have a garage check your alignment when fitting new tyres.

5. Don't Forget the Spare Tyre

Interestingly, the spare tyre is not checked during the standard MOT test. However, if you are currently driving on a space-saver spare wheel, the car will fail the MOT. The vehicle must be presented with four standard road wheels fitted.

6. Tyre Pressures and TPMS

While the MOT test doesn't explicitly fail a car for slightly low tyre pressures, a significantly under-inflated tyre will attract attention. More importantly, for cars registered after January 2012, the Tyre Pressure Monitoring System (TPMS) warning light on the dashboard must be functioning correctly. If the TPMS light stays on, it is a major MOT failure.

Taking 5 minutes to inspect your tyres using these steps will ensure your car is safe, legal, and ready to pass its MOT tyre inspection without any nasty surprises.