The "Road Vehicles (Construction & Use) Regulations 1986", specifically Reg.. 24 to 27, specify exactly what types of tyres can legally be fitted to your vehicle. THESE NOTES HAVE BEEN EXTRACTED FOR GENERAL INFORMATION ONLY: THEY MUST NOT BE TAKEN TO REPRESENT THE LAW.

REGULATION 24 :
This Regulation specifies what type of tyre may be fitted to different classes of vehicle, and any conditions and/or exemptions that apply. As far as those dealing with trucks and/or cars are concerned one item covered is the restrictions on the fitment of tyres that are 'Regroovable' (referred to in the regulations as 'Re-cut' ). The fact that no regrooved pneumatic tyre may be fitted to a motor vehicle with an unladen weight of less than 2540 kg demonstrates the principal limitation on the use of such tyres. This Regulation also defines the vehicles to which 'Temporary Use Spare Tyres' may be fitted.

REGULATION 25 :
This Regulation is concerned with the tyres load index and speed ratings. It specifically deals with, items such as the tyres fitted to Goods Vehicles, Buses and Trailers and for which a Ministry Plating Certificate must have been issued, and a Ministry Plate attached to the vehicle. Amongst other vehicle information the Plate, which must be securely attached to the vehicle in a conspicuous location, gives the maximum axle and gross vehicle operating weights. The Regulation requires that the tyres fitted to the vehicle are not only capable of supporting the maximum permitted load on each axle but of doing so at the vehicle’s maximum legal speed. In defining “load–capacity index” and “speed category” the Regulation makes reference to UN ECE Regulations 30 and 54 and to the European Union Directive 92/23/EEC.

REGULATION 26 :
Deals with the mixing of tyres of differing structures. The regulation defines three types of tyre structure, diagonal ply (Crossply), bias-belted and radial. No vehicle shall be fitted with tyres of differing structure on the same axle. For cars and vans (even with twinned rear axle), the following are the LEGAL tyre combinations.

Front	Rear
Diagonal ply (Crossply) Bias belted Radial Diagonal ply (Crossply) Bias belted Diagonal ply (Crossply)	Diagonal ply (Crossply) Bias belted Radial Bias belted Radial Radial
Mixing of a temporary spare tyre on a car is allowed, provided it is not driven at a speed exceeding 50mph.

REGULATION 27 :
Deals with the condition and maintenance of tyres. It specifies when a tyre should not be used on the road due to for example:- it not being suitable for the use to which the vehicle is being put, or issues relating to its condition or maintenance, such as inappropriate tyre pressures, cuts, bulges or tyre damage. It also allows the use of run flat tyres when in a deflated state provided the tyre and wheel are so constructed to be fit for the use to which the vehicle is being put. This Regulation also specifies that the grooves of the tread pattern of every tyre fitted to cars and light vans shall be of a depth of at least 1.6mm throughout a continuous band comprising the central three quarters of the breadth of tread round the entire circumference of the tyre.

In accordance with these rules, look under the heading "Find your tyre" for the alternatives offered by MICHELIN for each vehicle model.