i built up this old trek 800 18". i should be on a 20" but for snow riding with ancient legs a little closer to the ground doesn't seem to hurt things. the roads have been mostly clear with short snow falls like in the pic. the pic is after 8 miles in the snow with no problems other than having to push the 2" wide knobby tires. it helps to only use the rear brake so you don't wash out the front end and keep your speed down. if you are really worried about traction you can go studded tires. note that the seat is higher than the bars, keeping the weight bias forward and the wheel well planted. i have done 10+ miles on this set up no problem, except for cold toes.