It’s often said that we should spend good money on the things that separate us from the ground: comfy shoes, an ergonomic mattress, and reliable tyres.
We often don’t think about the rules surrounding our car and the roads since passing our theory test. But tyre rules are so important that it’s a concern how often they’re neglected. This article looks into the UK’s legal statutes and MOT testing criteria regarding tyre tread depth, sidewall damage, and tyre age.

Decoding UK legal minimum tyre tread depth requirements
UK law mandates a minimum tyre tread depth of 1.6mm – this is the figure that should stick religiously in your mind. It must be at least this across the central three-quarters of the tread breadth and around the entire outer circumference (for most vehicles).
The ’20p test’ is useful, where the outer band of the coin should no longer be visible when placed inside the treat. A calibrated tread depth gauge is more accurate though, for precise measurement.

Tread depth is of course needed for optimal grip, particularly in poor weather, along with reducing aquaplaning risks. Keeping your vehicle fitted with appropriate tyres, like 13 inch all terrain tyres for certain 4X4s for example, is just as important.
Assessing tyre sidewalls
From the source AUTODOC UK: “tyre sidewalls must be in good condition without any significant damage, such as bulges, deep cuts, or punctures, to comply with legal requirements. Tyres with damaged sidewalls will not pass an MOT, as such issues compromise their safety and performance on the road.”
Essentially, cuts deep enough to expose the ply or cords are a straight failure. Regulations often stipulate that cuts exceeding 25mm in length (or 10% of the tyre’s section width) and exposing internal cords constitute a failure. You can get away with some minor superficial scuffs that aren’t penetrating to the cords, but they should be closely monitored.
When does a tyre become too old?
A tyre’s manufacturing date is encoded within the DOT code – it’s imprinted on the sidewall. The last four digits usually show the week and year. Current UK MOT regulations state that tyres fitted to the front axle which are ten years old or more (or even rear axle if it’s a minibus) will result in an MOT failure.
Plus, if the tyre doesn’t display a legible date code, it will also be an MOT failure because it can’t be checked.
But, these are all failure points – it doesn’t mean we should run it to the wire, of course. Best practice strongly advises the replacement of any tyre exceeding 10 years from its manufacture date, regardless of tread depth or which axis it’s on. Signs of ageing should just be dealt with promptly.

Prioritising tyre safety
Your tyres are what directly connect the heavy machine you’re driving and the road. A good set of tyres with minimal ageing will improve your handling and braking, keeping you safe, and ensure that you pass the MOT without any issues. To achieve this, it’s best to build up the habit of checking your tyres every month or so.