I knew someone on this site would find something wrong with my math. Looks like I halved everything. Not sure why.This handy website says the difference in diameter (and, thus, circumference) is 6%.
Nominal diameter of a 225/65R17 tire is 28.5" according to the tire size website. As someone noted, 11/32" tread wear (1/4" + 3/32") reduces the radius, not diameter, by that amount, from 14 1/4" (14.25") to 13 29/32" (13.90625"), about 2.4%.
The spare is intended for temporary use at limited speed for a limited distance. Long distances and high speed with mismatched tires is different, even if the mismatch is much less.
Still. I get the spare is intended for temporary use and that's all I plan to use mine for.
Do you see any potential issue with using a full size matching spare but only doing a 4 tire rotation?
At no point in the tires life would it exceed factory differences according to my wrong but still applicable math.
The plan is just to use it to limp it to a shop assuming I can't patch on site.