ketchup

reccently, due to the horrible alignment that i have in the front. My front tires were worn to the fabric. I replaced them and put the new yoko ES100's on the rear and moved the spec2's to the front. The ES100's are supposed to have more grip than the spec2's. Thing is, while i was driving home i noticed a bit of sliding in the back. It just felt that the rears were sliding around while i changed lanes and made turns. I dont understand why it would feel like this other than the rear tires just having less grip than the fronts. whats goin on ?!