The guy at the shop told me that if I wanted to use my full size spare as a replacement tire that the tread would have to be within 3/32 to the other tires on my car. He said that if they weren’t then it could cause all sorts of problems. Is this really the case? The other tires aren’t even a year old with not too much wear.
With full-time AWD or 4wd your guy is quite right in running tires close in wear. Otherwise you can cause ($$$) damage to your transfer case.
The tread is unimportant. It’s the circumference of the 4 tires on the ground that is important…They must be very close…