Hey Beej, it wasn't the straights so much, as fast sweepers, and particularly the quick left- right transitions. I think the sidewalls are a bit compliant... probably a concesion to airing down, or absorbing sharp object impact. Don't misunderstand, they are awesome tires, big improvement over the "Stones" and if I hit dirt at all, they would still be on the VX. Yeah, they are 18's by the by.