Your tyres are the only part of your car in contact with the road. Everything else — your brakes, your steering, your suspension — depends on those four patches of rubber gripping the tarmac. Yet tyres are one of the most neglected parts of a vehicle, and worn tread is consistently one of the top reasons cars fail their MOT in the UK.
What Is the Legal Minimum Tread Depth?
In the UK, the legal minimum tyre tread depth for cars is 1.6mm across the central three-quarters of the tyre, around the full circumference. Driving on tyres below this limit is illegal and can result in a fine of up to £2,500 per tyre, plus three penalty points on your licence. More importantly, tyres below the legal limit have significantly reduced grip, especially in wet conditions.
Most tyre safety experts — and we agree — recommend replacing tyres when the tread reaches 3mm rather than waiting until 1.6mm. Tests have shown that stopping distances in wet weather increase dramatically as tread depth falls below 3mm. The difference between 3mm and 1.6mm can add several car lengths to your braking distance at 70mph.
How to Check Tread Depth at Home
There are three easy ways to check your tyre tread depth without any specialist equipment.
The 20p coin test: Insert a 20p coin into the main tread grooves of your tyre. If the outer band of the coin is hidden when inserted, your tread is above 3mm and you are fine. If you can see the outer band, your tread is getting low and you should get your tyres checked professionally.
Tread wear indicators: All modern tyres have small raised rubber bars moulded into the base of the main tread grooves. These indicators sit at exactly 1.6mm. If the surface of your tyre is level with these bars, your tyre is at the legal minimum and must be replaced immediately.
A tread depth gauge: These cost just a few pounds from any motor factors or online retailer and give you an accurate reading in seconds. If you want to monitor your tyre wear precisely, this is the best option.
Where to Check
Do not just check one spot. Tyre wear can be uneven — worn in the centre, worn on the edges, or worn more on one side than the other. Each pattern tells you something different about your vehicle. Centre wear usually means the tyre has been over-inflated. Edge wear suggests under-inflation. One-sided wear can indicate a wheel alignment or suspension problem. Check the tread depth in at least three places across the width of each tyre, and on all four tyres.
How Often Should You Check?
We recommend checking your tyre tread depth at least once a month and before any long journey. It takes less than two minutes and could save your life. While you are at it, check the tyre pressures too — under-inflated tyres wear faster, reduce fuel economy, and affect handling.
When to Replace Your Tyres
As a general rule: replace at 3mm for safety, and you must replace at 1.6mm by law. If you notice uneven wear, get your wheel alignment checked at the same time — fitting new tyres on a misaligned car will just wear them out prematurely again.
At AVS Bransgore, we stock a wide range of tyres for all vehicles and can fit them while you wait. We will also check your wheel alignment and tyre pressures as part of the service. If you are not sure about the condition of your tyres, pop in and we will take a look — no appointment needed for a tyre check. Call us on 01425 200826 or visit us at Bransgore Garage, Ringwood Road, Christchurch.
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