· The minimum legal tyre tread depth in the UK is 1.6mm across the centre 3/4 of the tyre. This applies to cars and passenger vehicles with up to 8 seated passengers (not including the driver) and motor vehicles & light trailers up to 3500kg gross vehicle weight. The tread depth has a significant impact on the stopping distance of a vehicle, particularly on wet road surfaces. A lot of vehicle manufacturers therefore recommend that you change your tyres when the depth reaches 3mm. In the UK, if you find yourself in front of a judge for illegal tyres, you can expect a fine of £2,500 and 3 penalty points per tyre…
· There are two main types of tyre construction, radial and cross-ply. It is illegal to mix the two types of tyre on the same axle (except in the case of temporary use), so you can’t put a radial on the front drivers’ side and a cross-ply on the front passenger side. They must both be either one or the other. You can however have two radials on the front and two cross-ply’s on the rear. Mixing brands and patterns is not illegal, although some manufacturers will recommend that you don’t do this – please refer to your owner’s manual for details relating to your particular type of vehicle.
· Tyres must be suitable for their purpose. This means the size and type of tyre and they must also be correctly inflated.
· No tyre is allowed to have a tear in its surface or a cut deep enough to reach the cording within the makeup of the tyre. There is also a size limit to the cut or tear which is 25mm or 10% of the tyre’s section width (whichever is the greater).
· Tyres should be checked for bulges or bumps which can be caused by the makeup of the tyre fracturing. These bulges are created by the tyre cording separating or tearing leaving only the actual rubber membrane to contain the air pressure and therefore weight of the vehicle.
· Given that it is only the contact area of the tyre that really wears away it makes sense to try and get some additional use out of the remainder of the tyre. This is where re-treads come in. However, all retreaded tyres supplied in the UK must comply with the British Standard for retreaded tyres (BS AU 144e). There has to be a very strict examination of the tyre before it can be resold and the at all stages it must meet the same load and speed ratings of new tyres. Also, retreads need to have at least 2mm of tread depth.
· For tyre longevity, safe grip and handling it is essential that tyres are inflated to their correct air pressure. Low tyre pressure will result in increased fuel consumption, shorter tyre life and increased risk of tyre failure. High tyre pressure can cause less grip, reduced stability when braking or cornering, greater risk of tyre impact damage from debris on the road and less comfort.
· Contrary to popular belief spare tyres, whilst stowed away, does not have to comply with tyre legal requirements. And, there is no obligation on the part of the MOT tester to inspect the spare wheel, although they may mention its condition in any advice note given with the MOT certificate. Once the spare tyre is fitted to the vehicle though, it will be subject to all of the legal requirements listed above.