How Do Under Inflated Tyres Affect Your Vehicle?

Bradley Jando | Monday 3rd May 2021 10:28am

Technician inflating a car tyre

It may seem like driving with under-inflated tyres is harmless but if you leave it for too long, you can have several problems on your hands before you know it! Read on to find out how under-inflated tyres affect your vehicle, and what you can do about it.

Uneven tyre wear

Tyre wear

When you drive with under-inflated tyres, the sidewalls of the tyre can become misshapen and bulge out because there’s not enough internal air pressure to hold the correct tyre shape. As a result of the sidewalls bulging, the edges of the tyre tread get much more wear than usual because they’re in contact with the ground more often.

This is actually a desirable thing in some rare cases, like with drag racers, because the slack tyres can grip the road enough to launch the car at the level of acceleration needed. But this is very precisely calculated for each race and, if you’re reading this, you’re unlikely to be driving a drag racer!

At best, this can cause premature tyre wear in normal cars – but if left for too long, excessive wear can lead to tyre bursts in areas where the rubber is too thin to hold the pressure.

If you see any particularly bulging parts of your tyre, you should be very careful of them when driving and get them replaced immediately.

Crucially, avoiding this excessive tyre wear makes it considerably cheaper for you – as you’re not having to replace your tyres prematurely.

Poor fuel economy

Fuel Economy

This is another by-product of the tyres making more contact with the road. Because there’s additional surface contact with the road, there’s more friction, which means that there’s more force holding your car in place – or, rather, there’s more friction slowing your car down.

This, in turn, means that your engine has to work harder to go at the same speed, so you end up using considerably more fuel than you should be.

Unresponsive steering

Because the tyre rubber has more slack in it when it’s in its unpressurised state (or at least its less-pressurised state), your steering will be more sluggish. That’s because it takes more of a side-to-side turn to actually turn the tyre itself.

Think about holding a strip of rubber, if you hold both ends tight and turn one end, it twists. There will always be a certain amount of twist in the rubber of your tyres, but tyres are developed to withstand a certain amount of necessary friction at the correct pressure.

So, not using the correct pressure here means that it becomes harder to control your car at speed – it’ll seem like it’s bouncing around bends rather than holding its grip on the road.

What to do about under-inflated tyres?

It’s quite simple, inflate them!

Inflating your tyres is easy – you can either use a paid air compressor at a petrol station (they’re usually between 50p and £1 to use) or use a 12v compressor at home.

It’s a good idea to regularly check your tyre pressures. You can do this by using your foot to put weight on the tyre, but this is a very rule-of-thumb method and requires some driving experience to know what the correct pressure should feel like.

If you have a 12v compressor, it’ll usually be able to give you a current pressure reading just by putting it onto the valve stem of your tyre. Either an analogue or digital gauge works – but some cheaper compressors could provide inaccurate readings.

It’s recommended to check your tyre pressures by doing this at least once a month.

Need to get your tyres checked?

If you need to get your tyres checked or replaced, get in touch with your Local Kwik Fit – for things you need to rely on, rely on the experts.

Any facts, figures and prices shown in our blog articles are correct at time of publication.

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