I bought Michelin Arctic Alpine's last year, and thought they were great, but we didn't get that much snow, so they saw a lot of time on dry pavement. This year looks much snowier. I drive a rear-wheel drive E28, and the front tires were barely worn, while the rear tires clearly had lost one layer of what seems to be a two-layer tread pattern. Are those tires still good? I just mounted them on the front, figuring the extra tread might be needed in back if I get stuck in deep snow. Any similar experiences w/ these tires?