Tires/Wheels - 3rd gen on 2nd

Few general questions here..

First: I have a set of 3rd gen sport wheels - the stock tire size is 265/65/17, am I able to run 265/70/17 instead?

Second: the above 3rd gen sport wheels are going to be my winter wheel/tire combo (they are pretty beat up) - for people that run two sets of wheels, what are you using as your winter tire? Studded/non studded?

Third: is it even worth having two sets of wheels/tires? I am trying to keep my Trail Runner wheels in decent shape - but i'm not wanting to throw a set of highway tires on for the summer, should I just put a good set of all terrain tires on the Trail Runner wheels and call it good?

I live in MT, so winters get pretty bad - we often have snow from late Sept-April. I only paid 20$ for the full set of 3rd gen sport wheels, so if I don't end up using them its not a big deal.

 

In MT, get dedicated snows if you can swing it financially AND have the storage space to run dedicated sets. You won't regret it. Blizzaks, of course, are the gold standard. Mounted on dedicated wheels is even better, you can swap them yourself without going to the tire shop twice a year. I have never run studs and never had the need. I do keep a set of tire chains in the truck in case the $hit really hits the fan, but have never had to use them.

If you can only afford one set OR don't have the storage space, at least get AT tires that have the severe weather "mountain-snowflake" symbol that are rated from winter use (NOT just "all-season" tires or M&S tires, not the same thing). There are a fair number of choices, but many people on TW seem to like the Falken Wildpeak ATs for the price.