I am mounting a set of 29x1850 15lt mickey thompson sportsman pro tires on my scamp. Tires say on the sidewall tube type tires. When I removed the old tires there were no tubes used. I purchased tubes when I bought the new tires and figured they were required. So I have repeatedly mouted these tires with the new tubes and cant get the hop out of them. Tubes show to be correct #. Two questions. 1. is it safe to ride around withe tube type tires with no tubes? 2. any advise on mounting them? I used the powder and what not. The old tires had no hop but also had no tubes.