b. Gearbox( except as specified in Art. 20. a above): Minimum 1010mm( 250cc and above: 1060mm) maximum 1270mm.
3.2. Track – Minimum two-thirds of the wheelbase.
3.3. Overall length – Maximum 1820mm without a front and / or rear fairing. 1880mm for 210 and 250 Gearbox. 2100mm including bodywork for all Gearbox when in Race Venue Event trim.
3.4. Overall width – All classes unless specified in Class Regulations Maximum 1400mm.
3.5. No part of the Kart can protrude outside the quadrilateral formed by the front fairing the wheels and the rear wheel protection nor be higher than 650mm from the ground( except for a structure solely designed as a head-rest).
4. Flooring
4.1. There must be a floor made from suitably rigid durable material that stretches only from the central strut of the Chassis Frame to the front of the Chassis Frame unless specified in Class Regulations and for Karts in Race Venue Event trim when the floor must be at least from the central strut of the Chassis Frame to the front of the Kart.
4.2. The minimum thickness of the floor tray must be 1.4mm for metallic 1.5mm for composite and 3mm for plastic.
4.3. The floor tray must be flat with any deviation allowed upwards and not downward.
4.4. The floor must be edged on each side with a tube or rim to prevent the Driver’ s feet from sliding off the floor.
4.5. If the floor is perforated on the horizontal surface with the exception of a hole to access the steering column fixing the holes must not have a diameter of more than 10mm and they must be apart by four times their diameter as a minimum.
4.6. It is permitted to drill additional holes for the specific purpose of mounting such items as pedal heelstops ballast sensors and fuel tank provided that the holes are restricted to the minimum size and number required to meet the purpose. Holes must not cause undue weakening of the floor tray at critical points.
4.7. It is permitted to use floor trays with decorative holes or slots so long as they are provided by the manufacturer and that the holes are in the raised sector( s) of the tray.
4.8. Mechanical fixings with more than three threads protruding on the underside of the floor tray are not permitted.
5. Suspension and Wheels 5.1. Any method of suspension including elastomeric material or by pivots is prohibited.
5.2. Wheels must be equipped with pneumatic tyres( with or without tubes) and the front wheels / hubs must be fitted with rolling element bearings.
5.3. Wheels which have been cut and welded are prohibited. 5.4. The attachment of the wheels to the axles / hubs must incorporate locking pins or self-locking nuts.
5.5. The requirement for wheel retaining locking nuts or secondary locking devices is waived for CIK-FIA Homologated wheels and their associated fixings.
5.6. Hubs with a single retaining bolt feature must not protrude beyond the end of the axle unless designed for that purpose and must incorporate a retaining device.
5.7. Extended hubs with one or two retaining bolts designed to overhang the end of the axle are permitted.
5.8. Any hub with an overall length( excluding wheel studs) of less than 60mm must not overhang the ends of the rear axle.
5.9. No form of hub nave plate is permitted on the wheel.
Motorsport UK National Competition Rules 2026 Edition 1
Chapter 18 Appendix 8- General Technical Regulations 668