Bought a 2007 Classic Duramax a few months ago and really like the truck. It has fairly new Falken 265-R70-16 tires on it with about 10,000 miles on them. I recently checked and found out the truck came with 245's so that explained why the speedometer seemed to be off. I crawled underneath and looked at the spare and it turned out to be an old 245 size so my question is would it be a big problem to run that 245 for a few miles with the 265's if I should have a flat out on the road and be unable to find a replacement Falken right away? I'm planning to hit the road with my 5th wheel camper this spring and was wondering if maybe it would be a good idea to pick up a size 265 tire to take along just in case of a disaster.