||Tractor pulling classes will vary slightly from association to
association, with minor rule changes occurring almost
annually. Therefore, we will not try and break them down
here, but recommend you take a look at a specific tractor
pulling association's rules (See Tractor Pulling
Associations). On top of this, there are also different
weight classes within the different tractor classifications.
Stock tractors, Pro-Stock and Super-Stock are factory
produced tractors that retain the original engine, rear axle,
gear box and look stock in appearance. Typically,
Super-Stock tractors are allowed up to three stage
changes using four turbo chargers. Pro-Stock tractors
are allowed one turbo-charger.