Skate Wheels
Roller skate wheels come in many sizes and hardness. Outdoor wheels have a softer wheel. A softer wheel is normally anything under 90A
Indoor roller skate wheels usually have a hardness of 90A or higher. Rec wheels are better for turns and speed wheels are as the name indicates best for speed skating.
The larger the wheel the faster the speed. You will be able to find wheels 57mm, 62mm, (which is the average size), 65mm and 70mm. Children who are just beginning to learn to skate should choose a small wheel.