IN A LITTLE JAM…

Truck came with 275/65R18’s two weeks ago I put on 285/70R17’s.

Some dickbag slashed the rear passenger tire.

I should be okay to drive home (50 miles away) below 70mph with the stock spare without blowing the rear differential right?.?.?.?.?.???

 

Yeah, but not ideal for sure

 

Biggest thing when driving with uneven tires is to go slow. I would limit to 55. Maybe stop after ten miles and feel the rear diff to make sure it's not cooking and if it's fine, you can go a little faster.

The deal is, that your diff will be spinning the whole time, rather than just when turning, so it will be working the fluid extra hard, and heating up. There is a 1-1 relationship between how fast you are driving, and how hard it is being worked.

 

I just need to get back home. Then I can get a new tire.

 

The new tire is barely any different than oem. It’s an open diff anyway. You’re fine regardless.

 

Like @Danman34 said, the difference is minimal - .6" on a new tire. That's less than the difference between a new tire and worn out tire of the same size. If my maths are correct, the smaller tire will rotate all of 10or 11 times more per mile if you were to drive in a perfectly straight line. You should be fine.

I very much dislike dirtbags that do stupid stuff like slashing a guys tires. Cowards.

 

Your math is good, only 12 revolutions per mile difference, yeah, that is insignificant. There will be no issues.

 

If it was a larger difference, sure, but for 12 revs per mile, its not worth the effort IMO.

 

Thanks everyone!

I was able to get my truck back home. I had to highway for about a half hour at 55 and then all side street for a half hour at no more than 45.

I did stop half way to let the diff cool but luckily it didn’t feel super hot. I could easily touch and hold it. I will probably change the diff oil soon though.

I am praying nothing got screwed up.

And I got a gouge in my brand new rim because the wrench slipped…

Tonight was a rough evening but this particular debacle is done with for today.

I am going to bed, thanks again to everyone!

 

You will be fine, as noted, the difference in tire size is trivial, and in this case, won't stress the diff any more than normal driving.

I've driven cars with mistmatched spares before where the diff got literally hot enough to steam, and was it was okay afterwords.