The reasons fall into three distinct categories.
Accident prevention
To drive safely, you need the right tyres in good condition, as they affect the steering, braking and acceleration of your vehicle. Worn tyres make it less predictable to drive and more likely to skid.
Skid resistance also varies a great deal on our roads according to carriageway finish† and the weather at the time.
On a wet road, worn tyres could mean that you need up to 70% more braking distance. For example, at a speed of 50mph you’ll need the following stopping distances depending on how worn your tyres are:
8 mm tread depth = 43 m braking distance
3 mm tread depth = 53 m braking distance
Less than 1.6 mm tread depth = 73 m braking distance
All this means it’s essential to check your tyres regularly and a good idea to change them when the tread reaches the 3mm level, rather than the legal minimum of 1.6mm.
Research from
† DfT (2007) Road Conditions in England: 2007
Staying within the law
Staying within the law
It is now illegal to have:
* Car tyres with tread worn to below 1.6mm;
* A mix of radial and cross-ply tyres;
* Over or under-inflated tyres;
* Tyres with cuts, lumps, bulges or tears;
* The wrong sort of tyre fitted to a vehicle or trailer.
* Car tyres with tread worn to below 1.6mm;
* A mix of radial and cross-ply tyres;
* Over or under-inflated tyres;
* Tyres with cuts, lumps, bulges or tears;
* The wrong sort of tyre fitted to a vehicle or trailer.
Penalties include substantial fines and points on your licence. Which is another good reason to check your tyres regularly.
Find out more about UK tyre law.
Saving money by reducing fuel consumption
Under-inflated tyres mean increased fuel consumption - which means you’ll have to spend more at the filling station.
So check your tyre pressures regularly and make sure they don’t fall below the recommended level. In fact, if you inflate your tyres 0.1 to 0.3 bar over the recommended level, it actually helps reduce road resistance and, with it, fuel consumption and CO2 emissions.
However, for safety reasons, you should never exceed the maximum pressure recommended for driving with a full load.