Tyres: reading the date code, pressures, rotation and when to replace

Tyres are the only part of the car touching the road. Here's how to check yours in five minutes.

How old are they?

Look for the four-digit date code on the sidewall, usually at the end of the "DOT" code. "2321" means the tyre was made in week 23 of 2021. Rubber hardens with age and heat even if the tread looks good, so many makers advise replacing tyres around six years old, whatever the tread. Check the date when buying "new" tyres too.

Tread depth

• Tyres have small raised wear indicators across the grooves at 1.6 mm. When the tread is level with them, replace the tyre.
• Grip in the rain drops well before that, so consider replacing at about 3 mm if you often drive in wet weather.
• Uneven wear (one edge worn, or patches) points to alignment, suspension or pressure problems.

Pressure

• Use the pressures on the sticker in the driver's door frame, not the maximum printed on the tyre.
• Check monthly and before long trips, with the tyres cold. Don't forget the spare.

Rotation and alignment

• Rotate every 10,000 km so they wear evenly.
• Check alignment after hitting a big pothole or if the steering pulls to one side.