Hex, Hi!

Here is my 'final answer' for the $1,000,000.

On the drive side of the bike the SunTour dérailleur is bolted into dropout. The little 10mm (I think) bolt should have a nut on the other side of it that is keeping the dérailleur attached to the bike. What that has done is moved the skewer/axle position forward from the rear of the dropout. Sounds pretty simple.

On the other side where the quick release is, there should be some sort of piece with a similar bolt and nut that keeps the axle from shifting backwards. When power is put to the chain it pulls the drive side forward and will actually pivot the passive side backwards. It's just shifting the axle around.

I'm explaining this as an ideal circumstance. If the skewer is really tightened up a lot it might not be a problem, but from what you have said thus far it sounds like it's going to shift no matter what the tightness of the skewer is.

The fix can be really simple, just a small bolt and nut fit into the dropout on the left side and tightened up will give the axle a firm anchor to keep itself from moving around.

Does this make sense?


Liz