Why Tyre Age Matters Even If Tread Looks Fine

Rubber is a natural polymer that gradually degrades through a process called oxidation, even when a tyre is not in use. The oils, polymers, and chemical compounds in the rubber compound slowly break down when exposed to oxygen, UV light, heat, and ozone. As this happens, the rubber loses its flexibility, becomes brittle, and can develop cracking — externally and internally.

Internal degradation is particularly insidious because it's invisible from outside the tyre. A tyre that looks fine on the surface may have significant internal cracking and weakening, making it prone to sudden failure — particularly at high temperatures generated during motorway driving.

Every tyre has a DOT code stamped on the sidewall. Look for the letters 'DOT' followed by a series of characters. The last four digits of the DOT code give you the manufacture date: the first two are the week of the year and the second two are the year. So '3522' means the tyre was made in the 35th week of 2022.

Check all four tyres — and your spare — for their manufacture dates. If any tyre is over five years old, have it professionally inspected. If any tyre is over ten years old, replace it regardless of appearance.

There is no single universal rule on tyre age limits, but the majority of tyre manufacturers and safety organisations recommend inspection from five years and replacement by ten years. Some manufacturers, including Michelin and Continental, suggest a maximum of ten years as an absolute limit.

Be especially vigilant with low-mileage cars, caravans, trailers, and motorhomes, which may have tyres that are old but still have significant tread remaining. On a car used only for short summer trips, the tyres might have years of tread left but be dangerously aged. Tread depth alone doesn't tell you everything — age matters too.