The basic idea of the tractor pulling race is to pull a heavy trailer (sled) along the race track as far as possible. The winner in the race is the one who is able to drive the longest distance and the aim is to make a “Full Pull”. The pulling tractors are divided into four different categories. For the standard agricultural tractors there are two classes, Super Stock and Pro Stock. The classes for self designed and built tractors are Modified and Minipullers.
Rules in short
The idea of the tractor pulling race is to pull a heavy trailer (sled) along a 100 meter long, clay-sand surfaced, ten meter wide track as far as possible. The trailer is built so that the drawing resistance increases along the race. While pulling, the weight on the trailer moves towards the front and increases the weight on the breaking device. The most successful in the race is the one who is able to drive the longest distance.
The aim is to make a “Full Pull”, which means pulling the whole hundred meters. In case there are several competitors making the Full Pull, the carriage is adjusted and a new race will be held. According to the new rules, in the rerun, a 110 meter track can be used to further decrease the possibility of a Full Pull.
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.
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- (4×2) or a three-axle (6×4) one . Only one drive shaft is allowed and the engine’s highest operating speed cannot exceed 2.800 rpm.