7.12. The spare wheel( s) or mounting( s) may not extend rearwards more that 200mm from a vertical line passing through the rearmost part of the original bodywork( excluding bumpers) or more than 100mm beyond the rearmost part of the original bumper position for the model of Vehicle whichever creates the lesser protrusion. An alternative maximum dimension not exceeding 400mm may be included in an accepted specification for a car in Class 7( c).
7.13. Class 2 Vehicles must use cross-ply tyres( which need not be listed in Ch. 8 App. 4 Lists 1 or 2 but which must not be of Grip Town & Country or Dual Purpose pattern).
8. Transmission 8.1. Be fitted with non-torque biasing differential in full and free operation between the driving wheels unless:
a. A differential was not fitted by the manufacturer. b. The Vehicle is restricted to running in a nominated Class or Formula.
8.2. Vehicles must be two-wheel drive only unless the Official Documents of the Event allow four-wheel drive.
8.2.1 Four-wheel drive vehicles operating in two-wheel drive mode are not eligible, unless Permitted by the Official Documents.
8.3. It is not permitted to change the gearbox or transaxle casing( except in Class 7( a) or 8) or Vehicles running to an accepted specification.
8.4. Original gear ratios may be changed.
8.5. It is not permitted to fit limited slip torque biasing locked or lockable differentials other than as provided for in 6 and 7( b) as standard equipment.
8.6. The rear axle casing must not be modified except for cars in Classes 7( a) and 8 and those cars in Classes 1 and 3 to 6 whose model and mark type was originally manufactured before 1955.
8.7. Vehicles may fit replacement differentials crown wheels and pinions provided the differential action remains free operating.
9. Electrical Systems 9.1. Vehicles must have a maximum of four forward facing beams in addition to side and indicator lights.
9.2. Auxiliary lights should not be used in non-competitive sections except in fog or falling snow as permitted by law.
9.3. All lights must be fitted and used in accordance with the Motor Vehicle Lighting Regulations.
10. Miscellaneous
10.1. Other than Ch. 7: and in the following sections there are no special requirements under Vehicle Regulations for: Chassis / Engines Suspension Brakes Steering Cooling Oil Systems Fuel Systems Electrical Systems Weight / Ballast Exhausts.
10.2. Auxiliary lamps unless fitted as standard equipment using gas discharge or LED technology are not permitted and gas discharge or LED headlamp units may not be retro fitted.
10.3. Any car which has been improved within the manufacturer’ s specification for the range will be considered as a production car.
10.4. The fitting of a safety roll-over bar is recommended. 10.5. The fitting of sump chassis and exhaust under-body guards and proprietary tow bars is permitted. 10.6. The footbrake clutch and accelerator pedals must all be in their original positions.
10.7. Silencing of Vehicles must be to the levels specified in Ch. 7 App. 8 Art. 2 with engines running at three quarters maximum rpm.
Motorsport UK National Competition Rules 2026 Edition 1
Chapter 17 Appendix 3- Technical Regulations- Classic Reliability Trial Vehicles
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