Originally Posted by
Scottrik
To me, the whole key is that the rear tires are absolutely fixed relative to each other so I'm not entirely convinced the whole "cross weights" thing exactly fits in it's entirety. Pseudo cross weights certainly, but changing at the front. In a stock car (or similar) the rear axle fixes the rear camber relative to each other, but it doesn't have the substantial mass of the car (motor/axle/gearing/hubs/pod) fixed on it and moving on a single pivot.
Would the "ideal" 1/12 have the motor mass perfectly centered? I would argue that the ENTIRE mass of the pod assembly would ideally be balanced side-to-side. I need to check into this, but I'd wager that our brushed motors are now more different in mass from different winds within the same manufacturers lineup. If that's the case, the centering and effect on balance would change with each different wind. Then you run into differences between manufacturers and different lines of motors and you're into a whole 'nuther realm of question. In the end, I honestly don't spend any time trying to balance the rear pod. I balance everything on the front chassis plate when I build the car and (effectively) tweak from the front with the rear sitting across the fixed bar.
I had to think about this for a while to get my head around it. I think we are talking about fairly small orders of magnitude in rear pod imbalance, so just balancing the front to “equal” works okay.
However, when I think back to the old days when I was running carpet oval with a Delta Villain, we would fine tune the corner speed with cross weights and you could defiantly tell the difference. From my experience cross weights do make a difference and should be the ideal way to set “tweak”.