The 24H Motos field is divided into three classes: Formula EWC (top class in the event and the FIM EWC), Superstock and Experimental. Endurance is one of only a few disciplines in which teams are free to choose their tyres for the world championship, so there is healthy competition between tyre manufacturers as well as teams. In the Superstock class, however, the exclusive supplier is Dunlop.
This is the prime category at the 24H Motos. The fork, damper, swing arm, brakes, radiator and exhaust may be changed as long as the general appearance complies with the homologated machine. A degree of freedom is granted to increase the engine performance level. These machines are fitted with a quick wheel change system. Teams select a machine among those authorised for the Superbike world championship.
These motorcycles are very similar to the original and therefore to the production model. Modifications are limited, especially relating to the mapping of the electronic fuel injection units. The engine must remain in its original configuration. Reinforcing the clutch and changing the air filter, silencer, internal parts of the forks, rear suspension unit, countershaft sprocket and rear wheel sprocket are allowed, as is mounting a steering damper and a quick-fill device for refuelling. The original wheel fasteners shall be used. Therefore good strategy and coordination will be required when changing the wheels on pit stops.
In both Formula EWC and Superstock, the fuel tank is enlarged to take up to 24 litres and a quick-fill device added.
In this category, the engine, main frame or suspension can be completely different to the original design. Experimental machines appear in the general classification of the race, but do not qualify for Endurance World Championship points. They are allowed to compete in the race if the Selection Committee considers the machine to be innovative and of technical interest. Electric machines can be entered in this class.