Warning. I don't know if you've encountered it yet, but our local crews in SE PA are using a cinder mix for traction on icy hills that includes ground silica, i.e. glass. The shards are very tiny and my tires picked up more than 20 tiny shards on each wheel. This caused multiple flats (8 for me in about ten minutes) and trashed a relatively new set of Michelin Pros and bot spare tubes I carry. My only advice if you encounter this stuff is that you take both tires off the wheel completely, and turn the casings inside out until you pluck out each tiny shard. Then carry your bike well away from the treated area. Otherwise, the tire will go again within a few hundred yards as the shards continue to work their way through their casings. My group was only 2, but the LBS described whole groups being laid immobile as people go through all the spare tubes and folks are literally stranded in the cold far from home. I have some of the toughest Contis mounted now, but my guess is that they will be no match for this glass if I encounter another big patch. A real bummer to be added to distracted motorists on cell phones, dogs, black ice, and brutal cold as deterents from riding outside in winter. The trainer is looking better and better until the spring rains wash this **** away.