Roller derby wheels

Roller derby wheels come in all kinds of different sizes. They can be really soft or they can be rock hard. So which wheel do you want? How soft should they be? How hard should they be? Don't worry, this is what I want to know too. 

What are soft wheels good for? 
Soft wheels are good for skating outside. This is because the softness of the wheels absorbs the bumps and it makes the ride smoother. Soft wheels are also good for having a good grip. If you are constantly slipping, this is what you want. But don't stop reading here, there is more to this! There are also disadvantages! If you are heavy and you have soft wheels you might find that everyone around you keeps passing you. Even if you are a light as a feather you might still find that it is hard to go fast on flat surfaces. Harder wheels are MUCH better for going fast. If you want to go fast while riding outside and having a good grip then I have a trick for you! Have two hard wheels and two soft wheels on each skate! Now that I suggested that you might be thinking Oh gosh! Why  didn't I think of this earlier?! 

So, now that you know that you can mix wheels together you might be wondering how many of each? Well, If you always ride inside and are always slipping but you don't want to lose any speed, then I would suggest one soft wheel on each skate. The other three should be hard. Now, where do I put this soft wheel on my skate? It depends. Are you slipping on your turns or crossovers? Or are you slipping while you are just going forward? If you are slipping on your turns you want to put it on the inside of your skate. It doesn't matter if it is on the bottom or the top just whichever one works best for you. So you can use these concepts to figure out how many soft wheels you need and how many hard wheels you need. If you have any question just leave me a comment. Also if you want to know more about this check out this website:
http://www.rollersandrevellers.com/rollers/lowdown-wheels/pushers

What are wheels made out of?
Wheels used to be made out of hard wood and clay. Now they are made out of a mineral called Urethane. Urethane wheels first started out as wheels for skate boards. Now they are also used for roller skates. Urethane gets the skater to go faster, grip better, and be better a skating all together now then when they were made out of wood and clay.

How is the hardness of a wheel rated?
It is rated on what is called an "A" rating scale. The higher the number the harder the wheel is, this allows the skater to roll more but have less grip. On the other hand, the lower the A rating scale is the softer the wheel is, allowing the skater to have more grip but to roll slower.
Thanks for reading everyone! 
Here is my drawing of a roller skate:

Thanks a lot,
Coco