Below are some general size suggestions based on the style of riding you might be interested in:
52mm-56mm: for street and park skating.
56mm-65mm: for vert ramps or cruiser boards.
65mm-70mm: for cruising or longboards.
HARDNESS / DUROMETER:
So what type of skateboarding are you going to do? If you are mostly going to skate streets and parks you will want a harder skateboard wheel. If you are mostly going to use your skateboard for cruising or transportation you may want a softer wheel that will be more forgiving on rough surfaces.
