I now have the Nitto Terra Grapplers on my VX, and need to buy a 5th tire to serve as F/S spare.

I've always put the F/S spare into my tire rotation to keep the circumference of all 5 the same. But since the NTGs have 7,500 miles on them, if I buy a brand new one, think the TOD will freak out? I'd imagine the difference is pretty small.

Thoughts?