I had the 18s on the truck with the Pirellis and never noticed any bump steer. As soon as I moved up to a 20" aftermarket wheel with Cooper Zeon LTZs, I *did* notice some bumpsteer under certian conditions but it's never been severe. I only say it was noticeable due to it not behaving that way with the 18s on it.

I'm sure we'll here from some of the guys/gals who run the factory 20s and what their experiences are with it.