If your heel slides up and down when you move around, chances are very good that you will develop a nice set of blisters every time you skate. Some skates have liners with special memory foams that conform to your foot, while others can be warmed with a hair dryer or heat gun to get a unique custom fit. Herein lies some of the biggest confusion among novice skaters. Wheels comes in all sizes and hardnesses. Choosing what's right for you is simply a matter of understanding their applications.
Aggressive skaters tend to migrate to small, hard wheels with a wide, flat profile.
Hockey players will look for a little more rounded profile than an aggressive wheel in about a 72 or 76 millimeter size. And recreational or fitness skaters, will also be in the 72 to 76 millimeter size but with an even more rounded wheel. Racing wheels are usually about 76 to 80 mm and have narrower profiles. A wheel's hardness is expressed in terms of a durometer number. The softer the wheel, the lower the number.