What are run flat tyres and how do they work?
Run flat tyres explained
Run flat tyres have reinforced sidewalls that can temporarily support the weight of the vehicle even after a complete loss of air pressure. This allows you to continue driving safely at a reduced speed to reach a garage, rather than being stranded on the roadside.
How they work
The reinforced sidewall is made from a thicker, heat-resistant rubber that prevents the tyre from collapsing when deflated. When a puncture occurs:
- The TPMS (Tyre Pressure Monitoring System) alerts you via a dashboard warning light
- You can continue driving at a maximum of 50 mph
- For a distance of up to 50 miles, though this varies by manufacturer
Common vehicles with run flat tyres
Run flat tyres come as standard on many modern BMWs, MINIs, and some Mercedes and Audi models. They are typically fitted to vehicles that are supplied without a spare wheel to save boot space and reduce weight.
Important requirement
Run flat tyres should only be fitted to vehicles equipped with a working TPMS. Because run flats are designed to feel relatively normal even when completely deflated, without a pressure warning system you may not realise you have a puncture until serious damage has occurred.
