Summer, winter or all-season tyres?

The right tyre depends above all on the temperature and your journeys:

• Summer tyres: above 7 °C, shorter braking distances and more precise handling, on dry and wet roads alike.
• Winter tyres: below 7 °C, a compound that stays supple and sipes that grip on snow and ice.
• All-season tyres: a single set all year round, ideal in town and on flat terrain for low annual mileage.

If you often drive in the mountains or drive long distances, two dedicated sets, summer and winter, remain the best choice.

Tread depth and age

In Switzerland, the legal minimum tread depth is 1.6 mm. The TCS nevertheless recommends replacing summer tyres from 3 mm and winter tyres from 4 mm: below that, braking on wet roads and grip on snow deteriorate significantly.

Age matters too: the DOT code on the sidewall gives the week and year of manufacture (for example 2324 = 23^rd week of 2024). Over the years, the compound hardens, even if the tread is still sufficient.

XL, runflat, C: the markings that matter

• XL (Extra Load): a reinforced tyre with a higher load index; often required on SUVs and powerful cars.
• Runflat (RFT, ROF, SSR…): lets you keep driving for a short distance after a puncture; to be fitted only on a vehicle designed for it, equipped with tyre pressure monitoring.
• C after the diameter: a tyre for vans and light commercial vehicles, designed for heavy loads.

As a minimum, match the load index and speed rating specified for your vehicle.

Reading a tyre size

The size is shown on the sidewall of your current tyres and in the vehicle documents. Example: 205/55 R16 91V

• 205: width in millimetres;
• 55: sidewall height, as a percentage of the width;
• R: radial construction;
• 16: rim diameter, in inches;
• 91: load index, here 615 kg per tyre;
• V: speed rating, here 240 km/h.

Tempted by another size? Our tyre size calculator shows sizes with the same diameter and how much they differ.