I agree with everybody here... Bad idea. Unless you're doing it for show ( ) you shouldn't be running a spare smaller than your stock tires. Dangerous...

 

Just change the spare to the other side half way home.

 

You need the spare to at least be the same diameter...especially if you have LSD or a locker.

Also, consider what trail conditions killed your good tire...could the spare get you back out of the terrain, or continue to enjoy your day off roading, in stuff that killed the good tire?

If you needed 37's to get somewhere, would a 35 get you through it too? (If so, do you NEED 37's anyway?)

With traction control, antilock braking, etc...if the tires are a different diameter, the computers are going to say the smaller tire is going faster...and apply the brakes to it to stop it from "slipping"....and, it will think you are turning towards the larger tire. as the smaller tire is "obviously on the outside of the turn, etc.

So - you WILL be crippled up/in limp mode, with a different diameter tire on one end.

Just get all 5 the same size, etc...and do a 5 tire rotation to make them all last/wear evenly.

 

Thanks.

 

no not joking, 10-12 lbs isn't going to hurt; you need to do more research

 

I think the question about the larger spare was the extra stress on the mount, not its inertia when on the axle spinning you up a hill climb, etc.