I have a winter bike that is sort of working out as planned. It is a mountain bike like the main commuter, and the plan is that in November I install studded tires and begin riding it when it snows. Then, in April, I put back the regular tires and use it as a backup. That use pattern is handy in Minnesota because in recent years the snow has not been reliable. Sometimes the roads are bare, sometimes covered with packed snow. I can switch bikes as needed. My "backup" for mechanical failure is that my six-mile route to work passes a bike shop, on a bus route, at about mile 2.5. I am officially able to fix a flat, but I struggle with it, and am pleased to spend money at the bike shop because a bike repair is so much cheaper than a car repair.