Every year many cars fail their MOT due to tyres that are dangerously worn. The good news is that with a few simple checks and adjustments, you can avoid that fail and stay safe on the road. Here are practical hacks to ensure your tyres meet the legal standard and help you pass your MOT first time.
What’s the Legal Requirement in the UK
Tyres on cars, light vans and trailers must have a minimum tread depth of 1.6 millimetres in the central three-quarters of the tread, around the full circumference of the tyre. This is the legal minimum. Any tyre worn below that level will fail an MOT.
Beyond tread, tyres must also be in good condition overall. They must not have bulges, cuts exposing cords or ply, visible damage, or mismatched tyres on the same axle.
Quick Hacks & Tests You Can Do Yourself
The 20p Coin Test
Use a 20p coin to check the tread. Insert the coin into the main tread grooves in several places around each tyre. If the outer rim of the coin (or the band around it) is visible, your tread is above the legal limit. If you can see that band clearly, then the tread is likely too low. It’s quick, free and effective. Perform this test about every two weeks and before long journeys.
Wear Indicators in the Tyre
Most tyres have built-in tread wear indicators (or TWIs) in the grooves. These are small raised bars at the base of the tread. When the tread wears down to the level of those bars, the tyre has reached the legal minimum. If you can see the indicator flush with the rest of the tread, you need to replace the tyre.
Depth Gauge
For a more precise check, use a tyre tread depth gauge (analogue or digital). These allow you to measure the tread in millimetres, so you can see how close you are to the legal limit. Use the gauge in multiple grooves around each tyre.
When to Replace Even Before the Legal Limit
Waiting until your tread hits 1.6 mm is risky, especially in wet conditions. Experts recommend replacing tyres once tread drops to around 3 mm. Some suggest even earlier depending on weather, driving style and road type. Below that level, wet braking performance can suffer significantly.
Replacing tyres earlier gives you a safety margin and reduces the risk of failing your MOT because of uneven wear or hidden damage.
Preventing Uneven & Rapid Wear
You can help your tyres last longer and keep tread more evenly by:
- Checking tyre pressure regularly and ensuring it matches what the manufacturer recommends. Under-inflation or over-inflation causes uneven wear.
- Having wheel alignment checked. Misalignment causes the edges or shoulders of tyres to wear faster.
- Rotating tyres (if appropriate for your vehicle) so that wear is spread more evenly across all tyres.
- Avoiding overloading the vehicle. Heavy loads make tyres work harder and accelerate wear.
- Adopting a more moderate driving style. Smoother acceleration, gentler cornering and careful braking help preserve tread.
Other MOT Fail Triggers to Watch
Even if your tread depth passes, you could still fail your MOT on tyre condition if:
- There is damage to the sidewall such as bulges, lumps, cuts or exposed cords.
- Tyres on the same axle are of different structures (for example radial versus cross-ply) or have vastly different tread patterns.
- Tyres are the wrong size, load rating or speed rating for the vehicle.
- Tyre valves are damaged or leaking, making the tyre visibly underinflated.
Pre-MOT Checklist
To give yourself the best chance of a pass, do this about a week before your MOT:
- Do the 20p test on all tyres and replace any that fail the test in multiple places.
- Check all tyres using the wear indicators and a depth gauge.
- Inspect sidewalls for cuts, bulges or damage and check for exposed cords.
- Ensure tyres are inflated to the correct pressure (consult your vehicle handbook or the sticker inside the driver’s door).
- If possible, get wheel alignment and rotation done, especially if wear seems uneven.
- Inspect tyres for correct size, matching pairs on each axle, and ensure load and speed ratings meet or exceed what is required for your vehicle.
Why These Hacks Matter
Tyres are the only part of the car in contact with the road. Proper tread helps channel water away, prevents aquaplaning and gives reliable grip when braking. Worn tyres increase stopping distances significantly, particularly in wet conditions. Failing to maintain good tread does not just risk an MOT failure, but also your safety and possibly your insurance. Putting in a little time now often prevents unexpected failures, fines or worse.
Conclusion
By following the hacks above you can reduce the risk of failing your MOT because of your tyres. Regular checks, replacing tyres before they become unsafe and keeping them in good overall condition all help. It is better to be proactive with tyre care than to wait until your MOT test looms. A good set of tyres with healthy tread not only helps you pass your MOT but also keeps you safer on every journey.