UK motorists are being urged to perform a simple '20p test' on their tyres before driving this summer, a check that can reveal if a tyre is nearing the legal minimum tread depth and may need replacement.
Why the check matters
Sudden summer downpours, especially after a dry spell, can leave road surfaces greasy as rain mixes with oil and grime. If tyre tread is already low, drivers are far more likely to lose grip when braking or steering on wet roads, according to safety experts.
The test involves slotting a 20p coin into the main grooves of the tread at several points around each tyre. If the outer rim of the coin is covered by the tread, the tyre should be above the UK's legal minimum. If the rim is visible, the tread may be too low and the tyre should be checked properly.
Expert advice
Ollie Green, car safety expert at Collect Service Go, said: "Most people don't think about their tyres until something feels wrong, but that's exactly why quick checks are useful."
He added: "Summer can give you long stretches of dry weather followed by a really heavy downpour, and that change in conditions can catch drivers out. If your tyres are already worn, you don't want the first time you find out to be when you're trying to brake or steer on a wet road."
Green advises doing the test in several places because tyres don't always wear evenly, and motorists should also look for obvious warning signs such as cracks, bulges, and uneven wear on the surface.
He said: "It sounds almost too simple, but it's a useful habit. It's important to remember that the 20p test isn't a replacement for properly measuring tread depth so, if you're concerned about a tyre, get it checked rather than relying on the coin test alone."
Legal limits and costs
In the UK, the legal minimum tread depth for cars is 1.6mm across the central three-quarters of the tyre and around the full circumference. Drivers caught below the limit can be fined up to £2,500 and receive three penalty points per tyre, meaning four illegal tyres could total up to £10,000 and 12 points, essentially an instant ban.
According to Checkatrade, replacing a worn tyre typically costs between £45 and £250 per tyre once fitted and balanced. For most everyday cars, drivers usually pay around £70 to £120 for a decent mid-range replacement, with prices varying by brand, tyre size, and whether the work is done at a garage or via mobile fitting.
