Pump up the Pressure – and Explode Your Tyres?
Is it a tyre myth that overinflation can burst tyres?
It’s easy to think of tyres like balloons; we’ve all burst one of those because we overinflated it. But will overinflation cause your tyre to burst? It’s one of the most common tyre myths. It’s time we explored it.
What is the correct tyre pressure?
The right tyre pressure for your tyres depends upon your vehicle. You’ll find the recommended tyre pressure on the tyre placard on the door jamb or in your vehicle’s owner’s manual. It’s not the tyre pressure on the sidewall – that is the maximum tyre pressure at maximum load.
Will overinflation increase the risk of a blowout?
If you overinflate your tyres and drive at speed, and hit a pothole or other debris, there is a risk that you could suffer a blowout. But that risk is very slim. If it does happen, it’s more likely to be because of an existing fault in the tyre.
The pressure at which a tyre burst is around 200 PSI. This is around 165 PSI higher than the average recommended tyre inflation pressure. You really would have to pump some air into a tyre to get its pressure up there.
So, is it safe to overinflate a tyre?
It’s certainly safer than underinflating a tyre, but you still wouldn’t want to overinflate your tyres.
When a tyre is overinflated, the tyre’s walls push out. The tyre becomes stiffer than it should be. This affects performance. Traction is likely to be reduced, as there is less rubber on the road. This also means that tyre wear will be concentrated along the centre of the tyre, with the likelihood of bald patches caused by hard braking.
You may also suffer increased fuel consumption because the engine must work harder to drive the vehicle forward on reduced traction. You are like to have a bouncier, more unstable and less comfortable ride. Tyre sidewalls act as second shock absorbers, softening the blow to your car’s actual shock absorbers. When you overinflate a tyre, the sidewall’s stiffness transfers directly to the shock suspension.
So, is it better to underinflate a tyre?
No! It’s more dangerous to put too little air in a tyre than too much. Underinflation puts stress on a tyre’s shoulders and sidewalls. The stress on the tyre’s steel belts can be enormous. With the temperature reaching as high as 200 degrees in this spot, the chances of tyre failure are massively increased.
When you underinflate tyres, you are likely to increase fuel consumption and increase wear and tear. You will need to renew your tyres sooner. But the big danger is the increased risk of catastrophic failure.
What the experts say
Unless you have a death wish or your tyres are defective, you won’t overinflate your tyres to bursting point. They are more robust than party balloons. However, overinflated tyres may be more at risk of bursting if you hit potholes, kerbs, or other debris at speed. Still, underinflated tyres are more dangerous.
“Your tyres will not explode simply by overinflating them. (However) overinflation will cause unnecessarily excessive wear on the tyre and reduce the amount of contact with the road. It will also cause drivers to assume that their vehicles are more responsive due to the reduced contact resistance between tyre and road.”
Having said all this, you should ensure that you don’t inflate your tyres to more than the tyre manufacturer’s recommended maximum (as displayed on the tyre sidewall). Further, you should always inflate to your vehicle manufacturer’s recommended tyre pressure, found on the door jamb and/or vehicle owner’s manual.
Not sure what tyre pressure is right for your vehicle? Feel free to contact us to book an appointment or ask any questions you may have.
Keeping your family and fleet safe on the road,