CHAPTER 17 TRIALS Appendix 5- Technical Regulations – National Trials Car Formula
Note:( 1) * indicates that additional information must be provided in the Official Documents
1. Eligibility
1.1. The National Trials Car Formula involves four-wheel Vehicles complying with all Technical Regulations except:
a. Ch. 7 App. 2 Arts. 6.5 – 6.9 and Arts. 22.4- 22.9. b. Period Vehicle Waivers. 1.2. Vehicles can be divided into two classes up to 850cc and over 850cc up to 1650cc. 1.3. Details of 750 Motor Club Trials Formula should be obtained from:
2. Safety
750 Motor Club, Donington Park Circuit, Melbourne Road, Castle Donington, Derby, DE74 2BN Tel: 01332 814548.
2.1. An electrical cut out switch per Ch. 7 App. 5 Art. 5 is mandatory. The switch must be located on the offside rear of the car and be rearward facing- see App. 7 Drawing 1. Ch. 7 App. 3 Art. 25.2 is recommended.
3. Chassis
3.1. Chassis construction is free but permitted wheelbase and width dimensions are shown in the App. 7 Chart 1.
3.2. Vehicle engines must be located with the centre of the foremost original manufacturer’ s sparking plug orifice not more than one-fifth of the wheelbase behind the centre line of the front wheel hubs where the only operative water radiator is mounted in front of the engine or one-eighth if no radiator is fitted in front of the engine( tolerance 1cm).
4. Body 4.1. There is no requirement for a windscreen or aero-type screen.
4.2. The bodywork must be of adequate strength and proper construction to provide a compartment for Driver and Passenger. It must meet the following criteria:
a. The front and rear overhangs must be as specified in App. 7 Chart 1. b.
c.
It must be equipped with fixed seats for a Driver and one adult Passenger and have seat backs not less than 30.5cm measured from the uncompressed base seat cushions along the angle of the seat back.
The rearmost portion of the seats( without cushions) at this 30.5cm height must not be behind a line through the vertical axis of the rear hubs.
4.3. All Passenger handles must be of rigid construction securely anchored and neither flexible nor adjustable.
4.4. No handle must be capable of touching the ground in the event of a roll-over and all handles must be sited so that in the event of the car hitting a solid object the handles are protected from contact with the object by the chassis.
Motorsport UK National Competition Rules 2026 Edition 1
Chapter 17 Appendix 5- Technical Regulations – National Trials Car Formula
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