Smaller Spare Tire Ok With G80?

[ramses355]

Got a question regarding tire size. 2007 NNBS 2500HD, found and bought a set of 17" factory aluminum wheels and tires for my truck. Tire size is 265 70-17 with a tire diameter of 31.7". Stock was 245 75-16 with 30.5" tire. I have the same spare tire (16")

I have the G80 locking differential in the back, 2wd.

Think I need to get a larger spare tire? Will 1" make a difference to the rear end if I get a flat? Looking through the tire rack site I was considering getting a BFG tire in 265 75-16 size with a 31.7 diameter if I have to.

Last thing, I carry a 2000 lb. Lance camper so the wife wants to be careful.

[Draenor]

From what I understand about the design of the G80, different tire sizes would not harm anything. You need one of the wheels to spin to engage the locking mechanism.

Someone else can chime in if I am mistaken.

[Zembonez]

I think an unloaded truck with the smaller spare for a few miles to get the original fixed would do no harm. With a load, I'd think twice about it since the two axles would be spinning at different rates and the diff would already be under a load. Just my .02

[mi.bowtie]

What Zembonez said. Also when turning you increase the ratio from side to side.

Your wife has the right idea. especially when towing.

Make sure the spare fits underneath in the frame. It should.