Spanish law requires that your vehicle is fitted with the correct type and size of tyre for the vehicle type you are driving and for the purpose it is being used. This means fitting the right tyres and for safety ensuring that they are inflated to the manufacturer’s recommended pressure.
The legal limit for minimum depth of the tread on your tyres is 1.6 millimetres, across the central ¾ of the tread around the complete circumference of the tyre.
What are principal grooves and tread depth indicators, and how do I find these?
Principal grooves are the wide grooves in the tyre tread which have the tread-depth indicators located inside them.
For safety reasons it is recommended that you replace your tyres before the legal limit is reached. Many vehicle manufacturers recommend replacing at 3 millimetres. At 1.6 millimetres in wet weather it takes an extra two car lengths (8 metres) to stop at 50 mph than if your tread was 3 millimetres.
A regular check of your tyres can help you to avoid 200 euro / each wheel in fines for having tyres worn beyond the legal minimum limit on your vehicle.