When I changed my car tyres, the tyre shop pumped up all four with air pressure of 220 kPa (32 psi, according to the conversion table). Is this okay? Why is tyre pressure important and how often do I need to check it?
There is no standard pressure setting for tyres. It varies according to the tyre size, weight of the car and suspension design.
Often, the pressure recommended for the front is not the same as for the rear. Refer to the owner's manual for recommended pressures for the front and/or rear tyres.
You will also find in it the recommended pressures for times when you carry a full load of passengers and when you are embarking on a long-haul journey.
Take note that the tyre inflation specification usually refers to "cold" pressure. If you have been driving for some distance, the tyres would have heated up and you should increase the setting by about 10 to 15 per cent.
The correct tyre pressure is essential for optimum all-round performance. That means dry and wet road grip, braking, ride comfort, tread wear and fuel economy.
Motorists often pay little attention to tyre pressure. Observe the tyres of a car you are following. Often, you will notice bulging side-walls, which means the tyres are under-inflated. This significantly increases fuel consumption and compromises grip. It also adversely affects steering precision.
Under-inflated tyres may in some cases improve ride comfort, but safety would be compromised.
Over-inflated tyres also result in a deterioration in performance. But as long as you do not exceed the recommended pressure by 20 per cent, it is quite safe.
It is a good idea to check tyre pressure once a month. Refer to your car's manual or the sticker on the driver's door sill.