Four Classes
The pulling tractors are divided into four different categories. Modified is the open class for self designed and built tractors. All types of parts are allowed as long as the weight and size are within the rules. In this class pullers can be seen with a jet engine from an aeroplane or a helicopter, or with five or six big V8 engines each generating hundreds of hp. The newest comers are the minipullers which resemble the modified machines but are much smaller and weigh only 950 kg.
Super Stock is a class for the standard agricultural tractors. The base of the tractor is a standard tractor and the engine, gearbox and rear axel have to be original. Also the appearance of the tractor has to be similar to the mass production model. Tractors in the Super Stock use metanol-powered engines.
The newest development is the Pro Stock class which like the Super Stock class, is based on standard agricultural tractors. The main difference is the less powerful engine as the tractor may be fitted with one turbocharger only. Also the tyres are a bit narrower. The maximum engine displacement is 8.364 cc and all tractors in the class have diesel-powered engines. Pro Stock tractor resembles very much the Super Stock tractor.
The standard agricultural tractors used in races cannot differ in appearance or equipment from the original ones. Difference is only allowed in the fuel systems. Rpm cannot exceed 2.800 r/min. In both classes (Pro and Super Stock) a tractor is classified only if a minimum of 150 units have been produced.
Weight classes
In each class the tractors are further classified based on their weight. In the Super Stock and Pro Stock tractors currently weigh 3.500 kg. The standard tractors are divided into four weight classes; 3.500, 4.500, 6.000 and 8.000 kilograms. The tractors are being weighted together with the drivers before each race.
There is also a separate class for trucks, where again, the appearance of the truck has to be original. The basic truck has to be a two- (4x2) or a three-axle (6x4) one . Only one drive shaft is allowed and the engine's highest operating speed cannot exceed 2.800 rpm.
Rules in Short
Classes