What does 86a and 83a means?

Answer 1

Those numbers represent a durometer/hardness of the material on what is called a Shore scale. There is more than one Shore scale. In the case for skate wheels the A (a) scale is used. The scale ranges from 0-100. The closer to 100 the harder the material gets. Within Skateboarding equipment you may find 101a. Although the scale does not go over 100, manufacturers use numbers above 100 so consumers do not get confused if they were to use another Shore scale like D. Now that you know, to answer your question 86a and 83a are 2 durometers that are pretty close together. In your hand you may not be able to feel the difference. Depending on your skill level and what you are doing, you may or may not tell the difference while skating.