So, the 190/55 is supposed to have a dramatic (bad) effect on the traction control? Hmmm. The 180/60's circumference changes as the center wears. Its circumference at one point will equal a new 190/55 on the 5.5" rim yet the TC still works. I doubt the effects are anywhere near as dramatic as people try to claim. I doubt most people saying how bad it is have never had a 190/55 on their 959.