The legal minimum tyre tread depth in the UK is 1.6mm across the central three-quarters of the tyre. 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, worn tread dramatically increases your stopping distance, especially on wet Welsh roads.
The easiest way to check at home is 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, your tread is above the legal limit. If you can see the outer band clearly, your tyres may be illegal and need replacing immediately. Repeat this test in several places across the tyre width, as wear can be uneven.
Tyre safety experts generally recommend replacing tyres when they reach 3mm tread depth, not waiting until the 1.6mm legal minimum. Wet-weather stopping distances increase significantly as tread wears below 3mm. If you are unsure about your tread depth or notice uneven wear patterns, call Royal Mobile Tyres Cardiff on 029 22714889 — we can come to you for a free inspection.