what needs to be replaced on my 3905?

[Tempted]

It really just sounds like the wheel is out of round to me. It was hard for me to decifer the problem from the grammer, though. I believe that you are saying one wheel wobbles more than all the rest. If it gets worse as you go faster, its probably just a tire out of round. If you can grab the wheel and "wobble" it up and down(like checking a wheel bearing in a car), try tightening the pillow balls. The "hub" that someone refers to is actually called the axle carrier or steering block. Very cheap but either its broken or its not. A picture would help more and a video would be definitive.