[bobcowan]

You adjust whatever is out of proper adjustment. I know that sounds like a smart-aleck answer. But the list of things that can cause that is long - from a slightly smaller tire on one side, to a bad steering rack.

Things to check are the obvious things like tire pressure and brake drag. And then start looking at alignment settings, ride height, and cross weights.

Don't forget to check the rear suspension, too. M ake sure the axle is square, etc.