I'm with randy on this one. The size difference is almost negligible, especially if the new one has little wear. If the 205's are more worn than the "new" tire then the difference will be even smaller still. I agree that in theory the smaller tire will cause undue wear and tear on the differential, but it'll never amount to much especially since these rears seem to be designed to outlive the car anyway.

I'd be more concerned about the unknowns associated with a used tire. But then if it looks good, isn't really old and it isn't the worst of the worst Chinese no-name brands then it's most likely just fine.

I'd rest easy, but have you son call when he gets home.

-Will
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854 - 244 - Mini

If that is a concern I am totally unaware of it.

Randy

I had a problem when I mistakenly put two different sized tires on the rear. One was off a donor. The difference in size was 185 70 r14 vs 185 75 r14. I had this weird unbalanced feeling in the rear like one tire was trying to catch up to the other one by bouncing every so often. I took it back in and thought the other tire which I had just replaced due to side wall damage was the cause but the tire tech noticed the different sizes and swapped it to the front. Two road hazard side wall punctures this year, no one out to cut my tires, legit road hazards. Never had one before this year.

I would say you did the right thing putting it on the front. That drive would have been miserable if it felt unbalanced back there.