I had all 4 changed in January then had an inside wall go on one of them and had it changed over with a new one I had heard this before so asked, and what he said is keep the same size tyre say 225/35 on the rear axle be fine. I have the same on the front's too,so I just bought another tyre and had it fitted But he was saying it wouldn't matter what tyre you have on the front could have 225/40 on the rear with 225/35 on the front. So I wouldn't have thought tyre wear would cause that much trouble.