Skateboard trucks are necessary to attach the skateboard deck to the wheels. There are 2 trucks required, made of aluminum alloy (typically), and they consist of two parts: the baseplate and the hangar. They provide a cushioning mechanism to the skateboarder, similar to shock absorbers. A kingpin nut determines how easy a skateboard can turn or does stunts. You can adjust the flexibility of the truck and the entire skateboard by tightening or loosening the kingpin nut.
Skateboard trucks have to be perfect in size compared to the wheels and the skateboard deck. A truck that has a larger than average axle can cause instability, and inevitable injury if not bolted properly.
