Between different skateboard types, decks vary in length, width, and profile. Generally, longer decks are reserved for longboards and cruisers as they offer increased stability and increased room underfoot. 

Trucks sit on the underside of the deck and are what attach the wheels to the board. In general, the width of the trucks should match the width of your board. 

Bearings are essentially what allow your wheels to turn, they have a big impact on how fast, or slow, your board rolls.

Bushings are the rings that fit around the kingpin (the central bolt that goes through your trucks to hold them together). They allow the board to turn and pivot smoothly and affect how responsive your trucks are. By tightening or loosening the kingpin, you can adjust how tight the bushings are and how easy the board is to turn. Bushings come in various stiffnesses, measured by a durometer, and in general, a softer bushing is more manoeuvrable, and a stiffer bushing offers a more stable and responsive ride.

Wheels vary in size and softness. Small wheels are great for tricks and smaller street riders, whereas larger wheels suit bigger riders, and importantly they roll better on rough surfaces as well as being faster. Longboards and cruisers will come with larger wheels than standard skateboards for this reason.