An aggressive wheel consists of a plastic core, which is connected with the outer urethane. The urethane contains the bearings and builds a solid basis of the wheels to lead them perfectly in the frame. All different urethane mixtures on the core across to the skater a particular skating feeling, depending on producer and mixture: It could be hard, soft, handy or fast – you can find everything in the range of the producers.
A hardness grade of a wheel is stated in "A" (shore hardness). As a rule aggressive wheels are between 85A and 105A. The higher the number, the harder the wheel. Wheels for skating are between 85A und 95A hard. Grindwheels are between 98A and 105A hard.
Soft wheels have a higher ride comfort as an uneven underground can be compensated easily. Besides this soft wheels have more road adherence (more grip). Naturally, it gives a more comfortable feeling to end up on the street after very high jumps. But their disadvantage is that they quickly fast up and therefore build a wider surface which leads to a higher friction and therewith to less speed. Soft wheels have approx. 85A until 88A.
Hard wheels offer a skating comfort which is not that high but give a direct skating feeling, slightly higher speeds and less scuffing. Durability is especially important for aggressive skating – therefore, hard wheels are preferred. Hard wheels have approx. 89A until 92A.
A size of a wheel is stated in "mm". Mostly, aggressive wheels for skating have between 53mm until 60mm. Most of all 55mm, 56mm and 57mm wheels are used. On the other hand, Grindwheels have 40mm until 50mm.
The bigger a wheel the higher speeds can be reached. But all so higher a wheel is road performance seemed to be groggy and stilted. If you use smaller wheels you have less speed but direct ground contact. The latter is what an aggressive skater is looking for. If the transmitted feeling is correct, the tricks will succeed!
All urethane-mixtures differ from wheel to wheel. The combination of different materials vary from producer to producer and naturally all manufacturers are committed to their own mixtures. We do not have any wheels in our range in which we do not believe. In our online shop you can only buy good and very good wheels.
If you want to know how you have to put a bearing correctly in a wheel we made a assembly instruction with pics