spare of different size...mostly hypothetical ?

Ok...so I've been running cooper at3s in 265/75r16 for a while now. I always mean to get a spare in the same size (if not necessarily the same pattern) but I just haven't gotten around to it. My spare is still 245/75r16.

First off, let me say I am planning to get a same sized spare ASAP. In fact, I'm looking to have 2 spares around JIC so sort of waiting for decently priced 265 on rim to show up on CL. Just had a question to help me determine how high of a priority to make this.

I get off road some but not generally for extended periods of time. I've pretty much always figured that on the highway if I had a flat I'd just throw the 245 on the non-drive front wheels until I could get to a shop. No big deal. However, if we were in the middle of a week long snow storm or I was pretty far off the beaten path and needed to be in 4x4 for extended periods of time, what are my chances of diff damage? Or, any damage?

 

With 2 open differentials, it's not really an issue mechanically. My concern would be the ABS or ALSD system acting up or trying to do something stupid.

 

Thanks for the input....gonna get that switched out soon.

 

I understand what you're saying but that's only if all 4 tires have great traction. You'll get binding in the transfer case in 4wd with any sort of turn even if all the tires are the same size. Something should be able to slip, relieving the stress on the transfer case, otherwise you probably shouldn't be in 4wd to begin with.

 

You could use your spare in 4wd and wouldn't have issues. Tire calc says it's 3.9% smaller in diameter (would use a tape measure to get a more accurate reading) which I wouldn't worry about.