Some drivers believe over inflated tyres make their car handle better. Others put too much air in because they believe it will save fuel. Whatever reason you do it for, it’s not a very good idea.
What happens with over inflated tyres?
When you put too much air into a tyre, the centre of the tread is forced down onto the road. This will make the middle of the tread area wear out more quickly than the outer edges. The result is tyres that wear unevenly and therefore more quickly than if they were correctly inflated.
Can it cause a safety problem?
When a tyre is over inflated, as we’ve already seen, the centre part of the tread is more in contact with the road. This effectively means there’s less of the tyre touching the ground. In wet conditions, there’s less tread capable of channelling water away in contact with the road. That makes water more likely to build up beneath the tyre and cause the car to aquaplane.
In dry conditions, over inflation can mean the edges of the tread area lose contact with the road. This can see the tyres give up traction, increasing the chances of you losing control through corners.
Lastly, over-inflated tyres can make the ride firmer.
Why it’s important to set your tyres to the correct pressures
Tyre makers spend many millions of pounds and man hours developing tyres that perform as well as possible. In some cases, they develop tyres for specific cars. These are called OE (Original Equipment) fitment and they’re the tyres your car was fitted with when it left the factory.
Tyres are one of the marvels of motoring. Not only are they designed to stop quickly and safely in the wet. They are also engineered to stop in the dry, corner safely in all conditions and perform a job assisting the car’s suspension to provide a smooth ride. Some tyres will even help you to save fuel. To achieve all this, the manufacturers design them to be run at certain pressures. You will find these in the car’s user manual.
Are there any benefits to over inflating tyres?
In some cars, when you look in the user manual, you’ll see a set of tyre pressures designed to help you save fuel. These will be higher than the regular pressures, but only by four to six PSI. So running tyres over inflated will help you to save fuel. This is because there’s less of the tyre in touch with the road. That means there’s less friction and so it takes less engine power to move the car.
Is it worth it? You might save a bit of fuel but the tyres will wear out much quicker. Really you won’t be making much if any saving. And the impact on road safety will be sufficient to make it a definite no-no.
I’ve been writing about cars and motoring for more than 25 years. My career started on a long-departed classic car weekly magazine called AutoClassic. I’ve since pitched up at Autosport, Auto Express, the News of the World, Sunday Times and most recently the Daily Telegraph. When I’m not writing about cars and motoring, I’m probably doing some kind of sport or working in my garden.