I just got new z rated tires on my car. Before that, I had H rated that were very worn out. My problem is, when I got the new tires I noticed that when I hit a bump the car will surge to one side of the road or the other. This never happend with the other tires. I am wondering if the fact that these new tires grip so well, that when I hit a bump one tire turns slightly and causes the car to turn. My friends car does it too and he has z rated tires. If anyone can help I would apriciate it.
Thanks,
Rob

 

Just a guess, but it probably has a lot to do with the fact that the sidewalls on the z rated tire are much stiffer than the h rated tire. The old tire was a lot more forgiving and would 'squish' going over bumps. The z rated tires are made to stand tall and not compress.