Longboard bushings - are they different?
The bushings for longboards are the same which are normally used on skateboards as well. The material is the same, namely polyurethane; the size is the same, and the hardness is also measured in durometers, marked with a number from 70 to 100 and the letter A.
The higher the number before the A, the harder the bushings are, and opposite, a lower number means softer bushings.
What you need to take into consideration though, is what kind of longboarding you do in order to pick the right hardness and shape of the longboard truck bushings. Harder ones are good for freeride and downhill (where you need stability) and softer ones are good for carving (where you look for more steering and responsiveness).
Bushings for longboards and their shape
The four main shapes the bushings come in are: cone, barrel, stepped cone, and double-stepped. Generally, the cone shape allows freedom of steering which is perfect for carving. The barrel, on the other hand, gives more stability and less motion which can still be used in carving but also freeride and downhill.
The other two shapes, stepped cone and double-stepped, are the more restrictive shapes. This means that you get limited motion but great stability which you normally look for at high-speed longboarding, such as downhill. The double-stepped bushing is the most restrictive and stable shape of longboard bushings.