What Run Flat Tyres?
Run-flat tyres are exactly that, tyres that allow you to carry on driving even if the air has escaped.
That doesn’t mean you can drive normally, though – once the air has escaped, you can only drive on a ‘flat’ run-flat tyre for a limited number of miles, and at a lower speed.
It’s worth noting that while run-flat tyres can be retrofitted to cars, they’re not recommended for cars without a Tyre Pressure Monitoring System (TPMS), as your car will give little or no indication that the tyre’s pressure is dropping.
What are the benefits of run flat tyres tyres?
The main advantage of run-flat tyres is that you can carry on driving if you get a puncture – assuming the sidewall itself hasn’t been significantly damaged. True, you have to be careful with how, how much and how fast you drive, but the distance limits run-flats come with should allow you to get to a garage or tyre fitters fairly easily.
Because of their strong sidewalls, run-flat tyres are also said to be less prone to blowouts – a rapid and potentially dangerous loss of air from the tyre.
Another advantage is there’s no need to carry a spare wheel, meaning the car’s boot can be a little bigger, or have under-floor storage where the spare would normally sit.
Are there any drawbacks with run flat tyres?
Run-flat tyres work well in many cases, but there are some circumstances in which they’re less than ideal. If you get a puncture late on a Sunday evening, for example, you may have to wait until Monday to find an open garage to fix it. It’s also possible your journey length will exceed the tyre’s limit, particularly if you’ve got to drive to your destination before making a second excursion to a garage the next day.
Speaking of fixes, because the sidewall may have been damaged, run-flat tyres must generally be replaced rather than repaired after a puncture. Run-flat tyres are also more expensive to buy than standard tyres, adding further cost.
Some drivers feel cars with run-flat tyres are slightly less enjoyable to drive, or aren’t as good at soaking up potholes and broken tarmac as cars fitted with conventional tyres. That’s because the stiffer sidewalls are less adept at absorbing bumps, and they also add ‘unsprung’ weight (mass that isn’t supported by the car’s suspension), meaning the suspension is less effective.