TECHNICAL RULES MOTOCROSS (INCLUDING RULES FOR ... - FIM

The ends of the mudguards must be rounded. The radius must be at least 3 mm.
Mudguards must be made of flexible materials only (e.g. plastic).
43.07
If cast or welded wheels are used, a protection must be provided by enclosing the
spokes with solid discs. Any open area between the outer edge of the solid disc and
the wheel rim shall be maximum 10 mm (tyre inflation valve excepted).
01.45 STREAMLINING
No type of streamlining is allowed (see diagrams), with the exception of motorcycles
in Cross Country Rallies.
Radiator covers (shields) must be made of flexible materials only (i.e. plastic).
01.46 SUSPENSION
Electronically controlled suspension systems may not be used.
01.47 WHEELS, RIMS, TYRES
47.01
All tyres will be measured mounted on the rim at a pressure of 1 kg/cm (14 lb./sq.in.);
measurements are taken at a tyre section located 90° from the ground.
47.02
Any modification to the rim or spokes of an integral wheel (cast, moulded, riveted) as
supplied by the manufacturer or of a traditional detachable rim (other than for spokes,
valve or security bolts) is prohibited. The only exception made is for tyre retention
screws, sometimes used to prevent tyre movement relative to the rim. If the rim is
modified for these purposes, bolts, screws, etc., must be fitted.
47.03 Restrictions for wheel (rim) dimensions
Capacity
Maximum front wheel
(rim) size
14
Maximum rear wheel
(rim) size
65cc 14 inch 12 inch
85cc SW
(small wheels)
85cc LW
(large wheels)
17 inch 14 inch
19 inch 16 inch