Years ago I tried slitting a piece of plastic pipe length ways and slipped it over the wear bar on my snow blower. It worked great on my gravel driveway, just floated right over the gravel. Problem is plastic and cold temperatures don't mix real well, and after a couple of snowfalls, the plastic shattered. I have heard that the poly wear bars do wear fairly fast on concrete and asphalt. So I suppose it depends on what you want to use it on.
Steve
Steve