What exactly are run flat tyres?
The feature that distinguishes run flat tyres is their specially reinforced sidewalls. This characteristic means that even when they are punctured, you can carry on driving on them for a limited number of miles and at a reduced speed. Usually, you can drive for a maximum of 50 miles at a top speed of 50mph on a punctured run flat, allowing you to get to a tyre centre to assess the damage.
This saves you from having to replace your car tyre at the roadside (which may be difficult or even dangerous) or call out emergency roadside assistance. As an added bonus, because you don’t have to carry a spare tyre with you in your car, you can benefit from a larger boot space and – thanks to the reduced weight – greater fuel efficiency and mileage. Importantly, run flats also make it easier to keep control of your vehicle in the event of a puncture, reducing the risk of an accident.
Because of their reinforced sidewalls, it can be difficult to tell you’ve got a puncture if you’re driving on run flats. This means all vehicles that use these tyres must also have a tyre pressure monitoring system (TPMS) fitted. Often, an alert from this monitoring system is the only thing that indicates to drivers that they have a puncture.
If your car has run flats and your TPMS warns you that you’re losing pressure in one or more tyres, it’s vital that you stick to the speed limit and mileage specified by the manufacturer and get your tyres changed as soon as possible. Your handbook will give you the details of these restrictions.
The fact is, run flat tyres aren’t designed to be used over long distances or high speeds after being punctured. Even though they may look fine to the untrained eye, it’s essential that you get to a tyre centre and have a specialist technician check them out. If you don’t, there’s a danger you’ll damage the wheel itself, which is much more costly than replacing your tyre.