What are run flat tyres and how do they work?

What Are Run Flat Tyres?

Run flat tyres have specially strengthened sidewalls that allow the vehicle to still be driven despite the loss of air pressure in the tyre(s). This means that you can drive to a garage without the need to stop on the side of the road to change a tyre.

How do Run Flat Tyres Work?

The rubber used for the sidewalls of run flat tyres is thickened and designed to withstand high temperatures, allowing the sidewalls to hold their shape after being punctured. When a run flat tyre is punctured a number of things can happen:

• The TPMS (Tyre Pressure Monitoring System) alerts you via a dashboard warning light
• The tyre can be driven on at a maximum of 50 mph
• The distance that can be driven on the tyre can be up to 50 miles, this is determined by the tyre's manufacturer

Which Cars Have Run Flat Tyres as Standard?

Run flat tyres are standard on many new BMW, MINI, and some models of Mercedes and Audi cars. Run flat tyres are also used on vehicles that do not come with a spare wheel so that there is more storage space in the boot and the vehicle weighs less.

An important note about run flat tyres

Run flat tyres should only be used on vehicles with a functioning TPMS. The driving characteristics of run flat tyres are designed so that they feel normal to drive and it means that the driver might not realise that they have a puncture until the tyre is damaged beyond repair.