Hong Kong Regulations

ROAD TRAFFIC (CONSTRUCTION AND MAINTENANCE OF VEHICLES) REGULATIONS - REGULATION 22

Tyres

(1) Subject to paragraphs (2) and (7), no wheel of a motor vehicle or trailer
shall be fitted with a pneumatic tyre that-

   (a)  is unsuitable having regard to the use to which the motor vehicle or
        trailer is being put or to the types of tyres fitted to its other
        wheels;

   (b)  is not so inflated as to make it fit for the use to which the motor
        vehicle or trailer is being put;

   (c)  has a break in its fabric, or has a cut in excess of 25 millimetres in
        length or 10 per cent of the section width of the tyre, whichever is
        the greater, measured in any direction on the outside of the tyre and
        deep enough to reach the body cords;

   (d)  has any lump or bulge caused by separation or partial failure of its
        structure;

   (e)  has any portion of the ply or cord structure exposed; or

   (f)  does not-

        (i)    in the case of a motor cycle the cylinder capacity of the
               engine of which does not exceed 50 cubic centimetres, show
               throughout at least 3/4 of the breadth of the tread and round
               the entire outer circumference of the tyre a pattern the relief
               of which is clearly visible; and

        (ii)   in the case of any other motor vehicle or any trailer, have a
               tread pattern (excluding any tie-bar) with a depth of at least
               1 millimetre throughout at least 3/4 of the breadth of the
               tread and round the entire outer circumference of the tyre:
               Provided that this sub-paragraph shall not apply in the case of
               a motor cycle with sidecar attached having 3 wheels in all, the
               weight of which does not exceed 100 kilograms and which is
               incapable of exceeding a speed of 20 kilometres per hour on the
               level under its own power.

(2) Paragraph (1) shall not prohibit the use on a road of a motor vehicle of
trailer by reason only of the fact that a wheel of the vehicle or trailer is
fitted with a tyre which is not fully inflated if the tyre and the wheel to
which it is fitted are so constructed as to make the tyre in that condition
fit for the use to which the motor vehicle or trailer is being put and the
outer sides of the wall of the tyre are so marked as to enable the tyre to be
identified as having been so constructed.

(3) No motor vehicle or trailer shall be fitted with a recut  pneumatic tyre
the fabric of which has been cut or exposed by the recutting process.

(4) Without prejudice to paragraphs (1) and (3), all the tyres of a motor
vehicle or trailer shall at all times while the vehicle or trailer is used on
a road be maintained in such condition as to be fit for the use to which the
vehicle or trailer is being put and as to be free from any defect which might
in any way cause damage to the surface of the road or danger to persons on or
in the vehicle or to other persons using the road.

(5) Pneumatic tyres of different types of structure shall not be fitted to the
same axle of a vehicle.

(6) A motor vehicle or trailer shall not be fitted with-

   (a)  a diagonal-ply tyre or a bias-belted tyre on the rear axle and a
        radial-ply tyre on the front axle; or

   (b)  a diagonal-ply tyre on the rear axle and a bias-belted tyre on the
        front axle.

(7) Paragraph (1) shall not apply to a land tractor, or land  implement, or to
an agricultural trailer when the trailer is being towed by a land tractor and
nothing in paragraph (1) or (3) shall apply to a broken down vehicle or to a
vehicle proceeding to a place where it is to be broken up, in either case
being towed by a motor vehicle at a speed not exceeding 20 kilometres per
hour.

(8) For the purposes of this regulation-

"bias-belted tyre" (交叉簾布緩衝層輪胎) 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;

"diagonal-ply tyre" (斜紋簾布層輪胎) means a pneumatic tyre, other than
a bias-belted 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;

"radial-ply tyre" (徑向簾布層輪胎) 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 stabilized by a substantially inextensible
circumferential belt;

"type of structure" (結構類型), in relation to a tyre, means a type of 
structure of a tyre of a kind as defined in this paragraph.

"bias-belted tyre" (交叉簾布緩衝層輪胎)

"diagonal-ply tyre" (斜紋簾布層輪胎)

"radial-ply tyre" (徑向簾布層輪胎)

"type of structure" (結構類型)