What dose the nitrogen in the rear shock do? I know why they use nitrogen, I just dont know what it dose. The reason I ask is because the shock on my kids 50 sx pro senior was leaking. I took it apart to fix it and can not see how it would have been charge with nitrogen. I have read that people will take a schrader valve and put on it to charge them, but the more I think about it the more I think that they do not charge these shock? Anyone know?