truetrac and spare tire

I have a rear end, 3.73 with truetrac from Kass, DoctorDiff, and for the tires,
front: 225x15x60, 25.6" diameter.
Rear: 275x15x55, 26.9" diameter.

I would like only 1 spare tire, if I have a 26.3" diameter, it will be ok for the truetrack?
Thanks

Your spare needs to be the same as the rear tire so you need to make sure it will fit in the front .

When was the last time you changed the oil in your true track ? I just removed one that appears to have been put together incorrectly by Eaton and it has been grinding itself to nothing , oil was full of metal and I had to beat an axle out of it.

Ok for tires diameter.
I didn't change oil again. Since I bought it, I drove 600 miles, no more.