Matching tire diameter for 16" rim with 31x10.5 r15 tires

Wrecked a 2000 and bought a 2002.

Wheels from 2000 had great tires and 15" rims. I swapped out the 16s on the 2002 before sending the 2000 to salvage.

I forgot to swap the spare so now I have 4 x 15" rims in service with a 16" spare.

What tire size would I have to get for my 16" spare rim to match my 31x10.5 r15 tires in service? I want the effective outside diameter to match fairly closely. The spare would not necessarily be a temporary fix but might have to carry me several hundred (possibly thousand) miles. I don't want to mismatch overall diameters.

Make sense?

 

31x10.5R15 is right in between 265/70R16 and 265/75R16, although if you have a brand new spare and worn tires, the 265/70 (~30.6") will probably be a closer fit. Also, tires from different manufacturers will be different sizes, the number on the sidewall is just a nominal size.

 

Just buy another 15" rim and be done .

Is there some reason you can`t??

 

x2 find a member close to you that's willing to trade.

 

Amen!