Skinny tires put more weight on a smaller surface area giving you more grip in slippery conditions. Stock tire on the runner suck. As everyone said, get new tires. I drove around today in the snow and had 0 under-steer. Sell your tires on CL and you will do much better than trading them in. BFG AT is a good tire, but they are a very old desighn and honestly there are other tires that are much more updated and will offer better traction in most scenarios. I would check out tires like the Cooper A/T3 or ATP, Duratracs (if you want more aggressive tread) or the Hankook Dynapro ATM. All of these tires are awesome and will get you through the snow without issue. (not talking s about the BFG I just feel that they are outdated and better choices do exist at this point) If you like you current gas millage then I would stick with the stock size. My current tires are great and I have only lost about 1mpg with the E rating. Good luck what ever you decide....tire buying is one of my favorite things.