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Sskafar 03-10-2011 09:41 AM

Spare tire size
I know you can't run a different size spare tire when in 4 wheel drive or all wheel drive without causing damage, but can I run a smaller size spare with the select a trac 4 wheel drive on a 2001 wj as long as I am in 2 wheel drive mode? Just wondering in case I put larger tires on and the spare needs to remain smaller to fit in the compartment.



TJXJWJ 03-10-2011 10:15 AM

Re: Spare tire size
I still think you'd fry the diff on whatever axle you had differing tires on. Even if it was up front and the front was disengaged....the diffs are still rotating.

Frango100 03-10-2011 12:00 PM

Re: Spare tire size
I think it all depends on which type of diff you have. The diff in fact is there to compensate for the different wheel speeds when making a turn (inner wheel will travel less distance then outer wheel, so will turn with a lower rev). So in that case a smaller wheel on one side would make the diff do the same as when making a turn and should not harm the diff. An other thing is when there is a Vari-Loc or Trac-Loc inside the diff. The limited slip additive is in the fluid to let the Loc slip slightly when making a turn. Letting it slip all the time due to a smaller tire on one side, this will definetly harm the Vari-Loc or Trac-Loc.
Not sure if the wheel speed difference would have any side affect on the function of the ABS system.

Sskafar 03-10-2011 12:49 PM

Re: Spare tire size
So if I had 31 inch tires and say my spare was 28 inches, in case of an emergency I could run the smaller spare tire on the front axle in 2 wheel drive for a short distance just to get to a service station without causing any problems? It would seem logical to me.


01grand 03-10-2011 02:36 PM

Re: Spare tire size
If you have the option for 2 wheel drive then YES you will be ok running different size tires for a short time, unless you have locking diffs (vari-loc which only comes with the quandra-drive all wheel drive package, or trac-loc which is sometimes used in the rear diffs only)

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