Friction as a bad thing
Reducing friction between the runners the and the snow has been a major concern for mushers for many years.
Before plastic musher would ether split a spruce log in half and peal it to make a smooth surface. However, the runners would dry out and loose some of their smoothness and they would also sink deeper then flat runners. They also used steel or iron runners. These floated better but didn't work well on exposed ground and tundra, and in addition to this the dog excrement would freeze to the medal runners and drastically increase the friction.
To day mushers have a wide variety of plastic runners to choose from that can be picked to mach the conditions that are he or she is facing that particular day. This has shown to reduce friction by many times that of the medal or wooden runners. Competitive mushers to day have to decide what density plastic they need before starting a race. If conditions are more favorable they might choose a softer plastic that will not give much resistance, but if conditions are harsh then they will try a harder plastic so that it doesn't gauge and scrape quite as easily.
