I have 33x12.50x15 BFG's on my 4Runner right now, I only have 4 and my spare is a 31". There are 4 used 32x11.50x15 BFG's on craigslist for $40. Are those 2 tire sizes close enought for me to be able to run 1 32" with 3 33" tires at highway speeds if i happened to get a flat tire and need to use the spare? Or should I wait until I can get a 33"?

 

on my last toy i had 31 10.50's and had to use a 30 9.50 as a spare for a couple days once. it was fine it just pulled slightly to the side the smaller tire was on.

 

If in that situation you should use it on the front with hubs unlocked.

 

Yeah could be a problem in 4wd with a smaller tire, but in 2wd it should be ok in a pinch.

 

maybe you could get away with a 33x10.50 but i wouldnt run a 32 as the spare (thats just me) hold out for a 33x12.50 its a common size (i just sold one on a rim with brand new tire for $60)

 

Dude it'll be fine with a 32 if you get a flat.

 

If your diff's are open, it shouldn't be a problem on either axle. It'll just track a little bit funny. That said, it's probably the best idea to get the same size spare - I'd just call around the local tire stores to see if they have an extra take-off lying around for $40. I once picked up a near-new mud tire for my spare for $30 (mounted & balanced). Those 32's are probably pretty beat anyway if they're going for that little.
Good luck

 

when my 33" bfg's were brand new, they were 32.8" tall. Let a few psi out and they will measure the same as the 32" tires.