Well, you probably want a sled that has as little friction with snow as
possible. Most plastics should work just fine for this purpose, but on
some days, the snow can be uncooperative. On a warm day, as the snow is
melting, the snow can be full of liquid water and get very "sticky".
Most kinds of sleds will be disappointing to ride when the snow is
sticky. Waiting for it to get colder outside may be just what's needed.
People who ski a lot talk about waxing their skis to make them
slide either better or worse, depending on what's desired. There are a
whole lot of different ski waxes, each designed for a different
temperature range for the snow. I'm not sure if ski waxes will stick
well to a plastic sled, though, and it seems like an expensive way
around the problem.
If the plastic sled is scratched up on the bottom, it also won't
slide as well. Don't drag the sled on rocks or the sidewalk before
using it on the snow.
Old-fashioned sleds have thin metal rails, called "runners" under
them. They should glide well on firm snow but may themselves get stuck
in deep, soft powdery snow. And nothing will help the sticky snow be
fun. The metal runners are good because you can bend them with a handle
in front and change your direction. I'm not sure they sell these much
any more because they can be hazardous if you run over anyone on the
hill with them.
(republished on 07/12/06)