When should you change your tyres? The signs that never lie

A tyre gives no warning when it is finished. It brakes a little less well, then a little less well again, until the rainy day when the car slides. Here are the six checks to make, once a month, in two minutes.

Tread depth

This is the main criterion. The law requires 1.6 mm minimum across the whole tread. But at 1.6 mm a tyre clears water very poorly: on a wet road the braking distance grows noticeably. We recommend changing at 3 mm for a summer tyre and at 4 mm for a winter tyre, which loses most of its grip in snow below that.

How to measure: every tyre has wear indicators, small bumps at the bottom of the grooves, marked on the sidewall by the letters “TWI” or a small triangle. When the tread is level with the indicators, the tyre is at 1.6 mm: too late. A depth gauge costs a few euros; otherwise, we measure your four tyres at every visit and give you the figures.

The age of the tyre

Rubber ages even without driving: it hardens and cracks. Look at the four digits after “DOT” on the sidewall: week and year of manufacture (“2219” = week 22 of 2019). Beyond five years, have the tyre checked every year; beyond ten years, replace it whatever its wear. This matters especially for cars that do little mileage, and for spare wheels.

Visible damage

Walk around the car and look at the sidewalls:

• a bulge (a lump on the sidewall): the internal structure has failed and the tyre can burst. Change it without delay;
• a cut that exposes the cords or the fabric;
• many cracks on the sidewall or at the bottom of the grooves: a sign of ageing;
• an embedded object (nail, screw): do not pull it out, see our page on punctures.

Uneven wear

A tyre worn on one edge only usually points to a tracking or camber problem. Worn in the middle: it has run over-inflated. Worn on both edges: under-inflated. Flat spots or saw-tooth wear: tired shock absorbers or an unbalanced wheel. In those cases, changing the tyre is not enough: the cause has to be fixed, or the new tyre will wear the same way. We tell you when we see it.

Vibrations and noises

A steering wheel that shakes between 90 and 120 km/h most often comes from an unbalanced wheel: balancing is enough, no need to change the tyre. A hum that grows with speed can come from uneven wear or a wheel bearing. If in doubt, ask us.

Pressure, every month

Not a sign of wear, but the first cause of premature wear. A tyre 0.5 bar under pressure heats up, wears on the edges and uses more fuel. Check the pressure cold, once a month, at the values printed on the door sticker. We check and adjust it at every visit.

Change two tyres or four?

Tyres are changed at least by axle: two identical tyres on the same axle. If you only change two, tyre manufacturers recommend fitting the new ones at the rear, even on a front-wheel-drive car: the rear is what lets go first on a wet road. And for winter tyres, four identical tyres are required.

Unsure about a tyre? Send us a photo on WhatsApp: we will tell you whether it is time to change, and we come to fit the new ones at your door.