Torsen diff and rear tire size sensitivity

[rumatt]

This morning I switched on my winter tires and headed to PA for Thanksgiving. While driving I kept thinking, "Hmmmm, somethings weird. It must be windy or something because I'm making a lot of steering corrections.

Then a few minutes later I realize that every time I stepped on the gas the car was turning slightly left. And when I let off it was turning right. At low speeds you didn't notice it but at 80 on a straight highway it is very noticeable, and actually incredibly annoying.

I hypothesized that the right tire might have more tread, making it a little bigger, thus putting down more torque now that I have an LSD.

I measured the tread depth with a quarter and couldn't see any difference. This left me scratching my head. What the hell else could it be?

I got to my parents and took both wheels off. Sure enough the right tire was just a little taller than the left. But we're talking less than a quarter of an inch (maybe 1/8th?) measured using a level. Could this possibly make that much of a difference??

So I swapped the wheels and sure enough, the symptoms reversed. The car now pulls right when accelerating (at least I think it does.. it was a crappy test on curvy roads.. I'll know for sure tomorrow.)

I think this is a problem that will go away on its own because the larger tire will wear faster. But I wonder if it's bad for the torsen gears to be working this much while it wears down?

I might also put more air in the smaller tire, but not enough to make them completely equal.

Either way... Torque vectoring diff FTW!