just to add to this, i was on low snow conditions this weekend, and thought the person in front of me had dropped something. i stopped, and reversed about 15 feet in maybe 3" of set up snow not remembering the scratchers were down. they survived, but don't think they would fare so well on hard pack trail. the fact the scratchers mount at the top near the tunnel and not the bottom, maybe hops over the snow instead of biting and breaking? just a thought, would not like to test that theory out. they don't have as much tension as i would maybe like, compared to a standard scratcher mounted on the bottom rail of a twin rail.