Our knowledge base for Drivers and Operators

Commercial vehicle tyres and the law

Mixing types of commercial vehicle tyre

The regulations are strict when it comes to mixing radial and cross-ply tyres. This is because of their different behaviours and the effect that could have on the handling of a truck.

  • It is illegal to mix radial and cross-ply tyres on the same axle.
  • In the case of a commercial vehicle with two axles, cross-ply tyres must not be fitted to the rear axle if radials are fitted to the front, unless the rear axle is fitted with wide tyres having a tread contact width per tyre greater than 300mm or having twinned-tyre wheel assemblies.
  • It is illegal to mix radial and cross-ply tyres on steerable axles.
  • It is illegal to mix radial and cross-ply tyres on two or more driven axles.
  • Legally, any two wheels of a commercial vehicle or trailer are regarded as one wheel if the distance between the centres of their areas of contact with road is less than 460mm. For more information, see 'Construction and Use Regulations' 26 and 27.

Tyre condition and the law

There are many legal requirements relating to the condition and use of tyres on commercial vehicles.

  • It is illegal to run a vehicle with a tyre at the wrong pressure.
  • It is illegal to run a tyre that has a cut longer than 25mm (or 10% of the section of the tyre, whichever is greater) or deep enough to reach the ply or cords.
  • It is illegal to use a tyre with a lump, bulge or tear, or with any of the cords exposed.
  • The tyre grooves must have a depth of at least 1mm around the whole circumference and across three quarters of the breadth of the tread. If the original tread pattern was only across three-quarters of the tread, all grooves must be at least 1mm deep.

Staying within the law can be complicated. At Tructyre ATS we know the law and keep up-to-date with developments and legislation. With our managed contracts and your daily checks, we'll keep your fleet's tyres legal.

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