hahaa - sorry mate, i cant actually answer that one till i get hold of some lipos and an ESC -lol- (Which btw will be an MGM 160-25 Z-Series and PolyRC 6000 MAh 6S 22.2volt 25C packs from the extreme series)

Could it be something to do with your servo arm position or travel possibly? Or maybe it's binding up somewhere? I cant tell for sure - but they appear to turn left/right equally, although i have no real way to tell untill i'm able to driv it - sorry mate.

But i did swap all the links out to the BOTTOM of the hub, and i still cant figure out how or why it happens... like - why the wheels turn left/right with up/down arm movement simply because of such a small placement issue!?!? I was looking at it last night, and STILL couldn't figure it out -lol- Anyways - thanks again bl-is-future - bloody lifesaver hehehe