Tyres are the only part of your vehicle in contact with the road. Worn or under-inflated tyres dramatically increase stopping distances and the risk of aquaplaning and blowouts.
Legal Minimum Tread Depth
The legal minimum tread depth in Sweden is 1.6 mm across the central three-quarters of the tread width for summer tyres. However, safety organisations recommend replacing tyres at 3 mm — below this, wet-road performance deteriorates significantly. Use the tread wear indicators (small raised bars in the tread grooves) — when the tyre surface is level with these bars, the tyre must be replaced.
Tyre Pressure
Under-inflated tyres flex excessively, build up heat, and wear faster on the outer edges. Over-inflated tyres give a harsher ride, less grip, and wear in the centre. Check the correct pressure (in bar or PSI) in your vehicle’s manual or on the sticker inside the driver’s door frame. Check pressure monthly and before long trips — always when cold (before driving more than 2 km).
Tyre Condition
Tyres with cuts, bulges, or damage must be replaced immediately — a structural failure at speed is catastrophic. Mix tyre types with care: avoid mixing radial and cross-ply tyres on the same axle.
Exam tip: The legal minimum is 1.6 mm but the safe recommendation is 3 mm. The exam may ask both — know the distinction.