Spare Tire Diameter ?

[cowboy701]

How close do I have to be on a spare tire diameter, to be able to travel 100 mi at most , without doing damage to the Diff ? I have 16" wheels 33 procomp tires, which measure 31" ground to top of tire. Just can't find a 16" used rim that will fit a Ranger around here, so I thought of having a large tire put on my spare 15" wheel and I might get close to the Dia. any thoughts ? BTW mine is a 02 4X4, Thanks

 

[RavoHimself]

well in ideal conditions it should be the same size. but you can be an inch or two off. but put the spare onto the front and the full size on the rear so both of your drive wheels are the same size. then everything will be fine. it might just pull to one side. but at least you can make it somewhere

 

[Irokranger93]

temporatly tire so shit driving truck with probably 135/90 D15

 

[88_Eddie]

as long as you dont use the 4wd, a difference in tire size wont matter. i used to have a p215 spare tire when i was running p235's, i only had to use it once, but it was fine that one time

 

[martin]

Just don't mix different sizes on an axle that has either an lsd or locker.

 

[4x4junkie]

Just don't mix different sizes on an axle that has either an lsd or locker.

^^
This.

A limited-slip diff will be damaged (rapidly worn out) by having different size tires on the axle. If you have to put a smaller spare on with a L/S, switch it with a front tire so the smaller tire is up front.
A locker won't be damaged, but your handling will be extremely strange though, so again, not recommended.
Open diffs (or selectable lockers unlocked), no issues (other than maybe a slight pull to one side like mentioned).

 

[cowboy701]

Well guys, you came thru for me again, and thanks, I was going out and buy a big tire and wheel tomorrow,probably about two hundred bucks, now I'll save that and just use my spare that(235/75/15) came with the truck, looks like it has never been on the ground, but it was down to 9 lbs. PO never checked I guess !! Thanks again