Tread depth
The table below shows the basic tyre tread depth requirements:
Type of vehicle | Minimum tread depth |
Cars, goods vehicles e.g. vans, not exceeding 3500kg | At least 1.6mm throughout a continuous band in the centre 3/4 of the tread and around the entire circumference |
Most other vehicles e.g. busses, large goods vehicles etc. | At least 1mm throughout a continuous band across at least 3/4 of the breadth of the tread and around the entire circumference. The original tread pattern must be clearly visible in the remaining quarter. At least 1mm where the original pattern did not extend beyond three-quarters of the breadth of the tread. |
Motorcycles over 50cc | At least 1mm throughout a continuous band across at least 3/4 of the breadth of the tread and around the entire circumference. The original tread pattern must be clearly visible in the remaining quarter. At least 1mm in where the original pattern did not extend beyond three-quarters of the breadth of the tread. |
Mopeds and motorcycles not exceeding 50cc | The original tread pattern must be clearly visible |
Other legal requirements
Generally, with some exceptions for agricultural vehicles etc., it's against the law to use a tyre that:
- is not suitably inflated for the use to which the vehicle or trailer is put.
- has a cut in excess of 25mm or 10 per cent of the section width of the tyre, whichever is the greater, deep enough to reach the ply or cord.
- has a lump, bulge or tear caused by separation or partial fracture of its structure.
- is unsuitable in regard to the vehicle's use or to the types of tyres fitted to the other wheels (this does not apply to temporary use spare tyres).
- has any portion of the ply or cord exposed.
- is not maintained in fit condition for the use to which the vehicle or trailer is put.
- has a defect that might cause damage to the road surface or to persons on or in the vehicle or using the road.
Age
Tyres degrade with age even if they aren't used very often but there are no hard and fast rules on when they should be replaced. Therefore, it's important to check tyres regularly for signs of aging such as cracks in the side walls, and replace them straight away.
Effect of less tread depth
Whilst the legal limit for cars is 1.6 mm, tests conducted by the Motor Industry Research Association (MIRA) found that once tyres are below 3 mm, stopping distances increase dramatically.
Expert guidance
If you are in any doubt as to whether your tyres are roadworthy, have them checked by a reputable garage/tyre fitter – they will be able to advise you.
