Have you heard of run-flat tyres? These aren’t a new thing. In fact, they were first introduced in the 1930s. However, as time has advanced, so too has the tech behind these tyres and the ones that are available today are built to withstand modern roads.
But what are they exactly? To find out more about the history of these tyres, along with an overview of the pros and cons behind them, read on.
What are run-flat tyres?
Run-flat tyres are designed to withstand a puncture and keep your car moving until you can swap the tyre for a non-punctured alternative. They’re able to do this because they feature a reinforced sidewall that is strong enough to keep the tyre’s rim suspended above the ground when it deflates. This means it continues to hold the weight of your vehicle as the air pressure in the tyre begins to fall.
This additional support buys you time as it allows you to drive at a lower speed, usually for a set number of miles, until you can pull over to a safe spot and repair the damaged tyre. For added peace of mind, these tyres are created by leading names, including Goodyear, Dunlop, and Bridgestone, as well as Michelin and Pirelli, and available from stockists such as Protyre.
While they were first introduced almost 90 years ago and developed during the second world war, it was in the 1980s that they became a standard addition to passenger cars. Since then, the tech behind them has become stronger and safer, thanks to years of testing and new ways of engineering tyres.
How far can you drive on a punctured run-flat tyre?
How your tyre pressure is monitored and the way you’re alerted to a drop in pressure depends on the type of car you have and the brand it’s made by. Modern models often have a tyre pressure monitoring system displayed onscreen that will let the driver know when there has been a puncture. For older cars, the manual will explain what the optimal pressure is.
You will also know how far you can drive on a damaged run-flat tyre as this is usually detailed in your vehicle’s handbook. As a general rule, most of these tyres allow you to drive no more than 50mph for 50 miles.
Your car will be set up for run-flat tyres. This means that you can’t simply switch a punctured run-flat tyre with a traditional one as your car’s suspension is designed with the run-flat tyres in mind. If you were to swap for a standard tyre, the handling would be very different and could ultimately cause an accident. Your insurance wouldn’t be valid, either.
What are the new tyres and how do they work?
In 2016, Bridgestone introduced DriveGuard tyre technology that changed things up. This is a run-flat tyre that’s self-supporting and can be fitted to any car that has a tyre pressure monitoring system.
While run-flat tyres allow the car to keep going at a reduced speed, the increased firmness of the reinforced sidewalls impacts on the drive quality. This means that the driver has to adapt how they drive until they can pull over and assess the damage.
DriveGuard was created using Bridgestone’s Nano Pro-Tech technology and this tech evenly distributes the air inside the tyre, reducing internal friction. A cooling mechanism inside the tyre’s sidewall also helps to reduce heat build-up.
The enhanced tech means that the impact of any bumps in the road are dramatically minimised, delivering a smoother drive. In addition, DriveGuard offers thinner sidewalls, and this helps to keep the overall weight of the vehicle down – a significant plus point when focusing on the reduction of CO? emissions and other types of pollution.
What are the cons of these tyres?
If you’re considering investing in run-flat tyres with this DriveGuard tech, it’s worth considering the cons too. First, the more accurate your tyre pressure monitoring system, the more likely it is that your car will register there is a puncture with these tyres.
Also, a punctured DriveGuard can only be repaired by authorised dealers, as long as the sidewall or the structure of the tyre hasn’t been affected. This means that you may have to ring around a few places to find someone who can help if you’ve got a puncture.
Additionally, although you can use a tyre inflation system if your DriveGuard run-flat tyre does encounter a puncture, Bridgestone recommends the tyre is inspected before you attempt to reinflate it.
There are also question marks around the EU tyre labelling scheme. DriveGuard received an ‘A’ for wet performance and ‘C’ for rolling resistance. While it may be challenging for run-flat tyres to achieve higher scores in these areas because of the stiffer sidewalls, this could be worth considering before you go ahead and buy.
Run-flat tyres have their plus points. They have the ability to keep you safe until you can switch tyres. However, the type you invest in will depend on your car and its tech.