Trucks
Trucks are the metal turning mechanism that attach the longboard wheels to the deck. They come in a wide range of styles, with wider trucks meaning a wider turning circle. They use the motion of the rider's feet and body to turn the board by pivoting a joint in the middle of the truck. There are generally two types of trucks used on longboards: reverse kingpin trucks and conventional skateboard trucks (vertical kingpin). Conventional skateboard trucks have the axle on the outside side (towards the nose and tail) of the kingpin, whereas reverse kingpin trucks have the axle on the inside side (towards the center of the board) of the kingpin.
Popular conventional skateboard trucks include Independent and Tracker. Popular reverse kingpin trucks include Paris, Randal, and Gullwing. Reverse kingpin trucks were created with longboarding in mind. While they are usually considered to have more grip and stability (two important things in the downhill discipline), conventional trucks have a very different feel that is often preferred by many longboarders.
Hanger width can greatly influence the turning characteristics of a truck. A wider hanger is thought to be more stable (turn less quickly). This is because the board generally has less leverage over the hanger, the wheels have a further distance to travel to get to an angle, and more board lean is lost due to bushing compression.
The angle of the baseplate can also greatly influence the turning and stability of a truck. As a general rule, as the degree gets smaller, the truck will be more stable, but turn less (its turn essentially becomes more vertically oriented rather than horizontally oriented). For example, trucks with 44 degree baseplates will generally be more stable (turn less) than trucks with 50 degree baseplates.
Read more about this topic: Longboard (skateboard), Components