Yes, your car will definitely fail its MOT if the tyre tread is below the legal 1.6mm minimum, or if it has serious cuts, lumps, or bulges. However, minor wear or ageing might only result in a pass with an advisory notice.
It's one of the most common questions I get asked as an MOT tester: 'Will my car fail on its tyres?' It's a sensible thing to worry about. Your tyres are the only things connecting your car to the road, and their condition is absolutely critical for your safety, especially when it comes to braking and cornering in the wet. The rules around tyres for the MOT aren't just about how much tread you have left. We look at the tyre's entire condition, and a failure can come from several different issues, some of which aren't obvious at a quick glance. Lots of people get caught out by uneven wear on the inside edge of a tyre, or by damage they picked up from a kerb or pothole weeks ago and have since forgotten about. Understanding what we look for during the test can save you the hassle and expense of a failure. A fail for tyres isn't just an inconvenience; if a defect is classed as 'dangerous', you won't be able to legally drive the car away from the test centre. Let's break down the official rules and what they mean in the real world, so you can go into your next MOT with confidence.
The official UK MOT rule
When we inspect your car, we're not just making it up as we go along. We follow a strict set of guidelines laid out by the Driver and Vehicle Standards Agency (DVSA). For cars (Class 4 vehicles), the relevant rules are in **Section 5.2.3 of the MOT inspection manual**. Here’s what the rulebook says, in plain English: **1. Tread Depth:** This is the big one. The law requires a minimum tread depth of **1.6mm**. But it's not quite that simple. This depth must be present in a continuous band across the *central three-quarters* of the tread's width and around the *entire circumference* of the tyre.
How testers actually assess this
When your car comes into the bay, the tyre inspection is one of the most hands-on parts of the test. We can't do it properly just by looking. We need to get up close and personal with every tyre on the vehicle. First, we do a general visual check as the car comes in. Then, once it's on the ramp, the detailed work begins. I'll take my tread depth gauge and check each tyre in several places. I don't just measure the middle; I measure across the width of the tread pattern, in the main grooves, to check for that 'central three-quarters' rule. People often get caught out by poor wheel alignment cau
Common scenarios — pass, advisory or fail?
Let's walk through some real-world examples I see every week in the test bay. This will help you understand the difference between a pass, an advisory, and a fail. * **Scenario 1: Tread is getting low.** You check your tyres and the tread seems okay, but it's not brand new. I measure it with my gauge and find it's 2.5mm across all tyres. * **Result: PASS, with an advisory.** The legal limit is 1.6mm, so at 2.5mm you are perfectly legal and safe for now. However, that's not a lot of tread left before you hit the limit. I'll add an advisory note like: `[001] Tyre worn close to legal limit/worn o
What to do if you're worried before your test
It's always better to find a problem yourself a week before the MOT than for me to find it during the test. A few simple checks can save you a lot of time and money. Here’s what you can do: **1. The 20p Test:** This is a brilliant, simple way to get a rough idea of your tread depth. Take a 20p coin and place it into the main tread grooves of your tyre. The border of the 20p piece has an outer band on it. If you can't see that outer band when the coin is in the groove, your tread is likely above the 1.6mm legal limit. If you *can* see the band, your tread is getting low and you should have it c
What happens if you do fail
Okay, so the worst has happened, and I've had to fail your car on a tyre. Don't panic, it's a common situation and there's a clear process to follow. You'll be issued with a VT30 'Refusal of an MOT Test Certificate', which lists the reason for failure. Tyre defects are categorised as either 'Major' or 'Dangerous'. * **If it's a 'Major Defect'** (e.g., tread below 1.6mm), your car has failed its MOT. You can't get a new certificate until it's fixed. If your previous MOT certificate is still valid, you can technically drive the car away to be repaired. However, be aware that you are knowingly dr
Are 'budget' tyres more likely to fail an MOT? — Not because of their brand, no. Any new tyre sold in the UK, budget or premium, must meet strict safety standards to be legal. It will pass an MOT perfectly fine when new and correctly fitted. The difference between budget and premium tyres is usually found in performance—things like wet grip, road noise, and how long they last. A cheap tyre on a car with bad alignment will wear out just as fast,
My TPMS (tyre pressure) warning light is on. Is that an MOT fail? — Yes, if your vehicle was first used on or after 1st January 2012. For these vehicles, a Tyre Pressure Monitoring System (TPMS) warning light that stays on indicates a system malfunction, and this is a 'Major Defect' which will fail the MOT. This is covered in Section 5.2.3 of the inspection manual. If your car is older than that, the TPMS system is not part of the test, but the light is still warn
What about the spare tyre? Is that part of the MOT test? — It depends entirely on where it's stored. If you have a spare wheel in the boot or secured inside the car, it is not inspected as part of the MOT. However, if your spare wheel is carried in a cradle underneath the vehicle, then we are required to check it. We inspect the tyre for its general condition and security, and also check that the mounting cradle itself is not corroded or insecure. A defec
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