Okay i am getting some 235/75/15 tires installed tomorow and i was wondering if i could use my old tire 215/75/15 as a spare?

 

you can but only for short distance's cause the the 215 would turn at a diffrent speed from the 235 and could possably mess up your axle from what i understand

 

depends on if you have a locker or limited slip. also you would only want to use it in an emergency. if one of your back tires goes then take one of same size off the front an put the smaller on the front that way its not working your rear dif so much. others may say its ok. im not sure it just seems right. imo

 

That's what I do, A 235/15 would be a tough fit in the spare location. It can be done, but the my cover doesn't fit then.