Will running a new spare tire (Front Right) with three pretty worn tires harm the the drivetrain?

 

Will running a new spare tire long term (Front Right) with three pretty worn tires harm the the drivetrain?

 

Welcome.

Not so long as they are the same tire make, model and size. I say that because different tires from different manufacturers may be different actual size/diameter even though the tire size numbers are the same.

If the other three are bald, you should not drive on bald tires. Check them with a tread gauge for 4/32 minimum.

 

Come on Doc (lol) in my neck of the woods (just outside Chi town and Milwaukee) the peeps drive till the threads and wires are hanging out.... literally had a guy knock on my door to borrow tools so he could change a flat tire. I don't loan my tools to anyone, so went out with them and stood by while he swapped a tire down to the wire with a bald patched tire.

 

I have a similar question will the stock spare “work”on the H3 when the other tires are upgraded from the 265 to 285’s thus slightly smaller - probably not right?

 

NOT is correct. When you carry a smaller tire on the back, you are just hauling it around because using it for a spare with cause issues in the Diffs and T Case.