Motor Vehicles (Construction and Use) Regulations (Northern Ireland) 1999

Mixing of tyres

31.—(1) Subject to paragraph (5) pneumatic tyres of different types of structure shall not be fitted to the same axle of a wheeled vehicle.

(2) Subject to paragraphs (3) and (5), a wheeled motor vehicle having only two axles each of which is equipped with one or two single wheels shall not be fitted with—

(a)a diagonal-ply tyre or a bias-belted tyre on its rear axle if a radial-ply tyre is fitted on its front axle; or

(b)a diagonal-ply tyre on its rear axle if a bias-belted tyre is fitted on the front axle.

(3) Paragraph (2) does not apply to a vehicle to an axle of which there are fitted wide tyres not specially constructed for use on engineering plant or to a vehicle which has a maximum speed not exceeding 30 mph.

(4) Subject to paragraph (5) pneumatic tyres fitted to—

(a)the steerable axles of a wheeled vehicle; or

(b)the driven axles of a wheeled vehicle, not being steerable axles,

shall all be of the same type of structure.

(5) A temporary use spare tyre may be fitted to a wheel of a passenger vehicle (not being a bus) unless it is driven at a speed exceeding 50 mph.

(6) In this regulation—

“axle” includes—

“a bias-belted tyre” means a pneumatic tyre, the structure of which is such that the ply cords extend to the bead so as to be laid at alternate angles of substantially less than 90 degrees to the peripheral line of the tread, and are constrained by a circumferential belt comprising two or more layers of substantially inextensible cord material laid at alternate angles smaller than those of the ply cord structure;

“a diagonal-ply tyre” means a pneumatic tyre, the structure of which is such that the ply cords extend to the bead so as to be laid at alternate angles of substantially less than 90 degrees to the peripheral line of the tread, but not being a bias-belted tyre;

“a driven axle” means an axle through which power is transmitted from the engine of a vehicle to the wheels on that axle;

“a radial-ply tyre” means a pneumatic tyre, the structure of which is such that the ply cords extend to the bead so as to be laid at an angle of substantially 90 degrees to the peripheral line of the tread, the ply cord structure being stabilised by a substantially inextensible circumferential belt;

“stub axle” means an axle on which only one wheel is mounted; and

“type of structure”, in relation to a tyre, means a type of structure of a tyre of a kind defined in this paragraph.