When to replace your tires: legal wear, age, and the signs that don't lie
Updated · Autofy
When to replace your tires: legal wear, age, and the signs that don't lie
In Europe and the UK, a car tire must be replaced at the latest when its tread depth reaches 1.6 mm, the height of the wear indicators; below that you risk a fine and a failed inspection. Tire makers recommend replacing earlier, around 3 mm for summer tires and 4 mm for winter tires, because wet grip drops well before the legal limit. Tires also age without being driven: after five years, have them inspected yearly, and replace them at around ten years at the latest.
The legal limit: 1.6 mm
European and UK law requires a minimum depth of 1.6 mm in the main grooves. To check without tools, manufacturers mould small raised bars, the wear indicators, at the bottom of the grooves, marked by a small triangle or the brand logo on the sidewall. When the tread reaches their level, the tire is at the limit.
Below it, you risk a fine, a possibly immobilised car and a failed inspection.
Why replace well before
Wet grip doesn't collapse suddenly at 1.6 mm: it drops gradually. The grooves clear water; the shallower they get, the higher the risk of aquaplaning. That's why makers such as Continental recommend replacing a summer tire at around 3 mm and a winter tire at around 4 mm, since snow needs deeper grooves.
Age matters too
Rubber hardens and cracks over time, even on a barely used tire: a car that rarely moves, a spare wheel, a caravan. Common recommendations:
- after five years, have the tires inspected every year;
- at around ten years, replace them regardless.
To find the age, read the DOT code on the sidewall: the last four digits give the week and year of manufacture. 2321: week 23 of 2021.
Other signs to watch
- Wear on both edges: under-inflated. The tire pressure light helps you avoid it.
- Wear in the centre: over-inflated.
- Wear on one side only: wheel alignment needs adjusting.
- A bulge on the sidewall: damaged structure, replace immediately.
- Cracks in the sidewall: ageing.
- Vibration at steady speed: balancing, or a deformed tire.
Track your tires
Autofy tracks your tires with a gauge that accounts for their mileage and age, and for the type fitted (summer, winter, all-season, run-flat). You know when to budget for new ones before you reach the wear indicators.