Skateboading Hardware is one the most important because is what puts together the skateboard, althought size is not important but quality and material is.

 

Skateboarding Barerings are all the same size and will fit any wheel you buy. Althought bearings do not vary in size, they do vary in quality. The more expensive the barerings are the better the metal quality is and sealing.

 

Risers pads in a skateboard prevent the hardware from vibrating loose. But for small decks with wheels 55mm or smaller don't really need them.

 

Bolts (hardware) are what keep your skate board attached to the trucks. So if you are going to use riser pads is better to get longer bolts just to be safe.

 

7/8" to 1" - No Riser
1" to 1 1/8" - 1/8" Riser
1 1/4" - 1/4" Riser
1 1/2" - 1/2" Riser