Spare tire? I’ve seen cars here in New Mexico sporting two at a time. Know why they’re called temporary spares? You can only get a couple hundred miles out of them.
If it was a typical emergency spare (low diameter) they are specifically prohibited from running even at 55 mph. (40 miles max distance I believe.) Much less 75!
If it were a cobbled replacement (regular tire was flat, another “ordinary tire” substituted) it could be any size, any mismatch as well.
“I’ve seen cars here in New Mexico sporting two at a time.”
I’ve got that beat.
Here in Montgomeradishu (Montgomery AL), I’ve seen locals riding with four of the little donut spares on their cars.