Freezy riders: Motorcyclists stay cool to race frozen lakes

These motorcycle racers seem to defy physics by buzzing around slick tracks plowed out atop frozen lakes and rivers each winter.

The riders on upstate New York ice this winter are butchers, contractors, maintenance workers, fathers and sons.

Some compete for money, with purses up to $500 on a recent race day. But most are amateurs, risking the ever-present threat of slipping sideways across the ice for thrills and post-race laughs.

Racers ride standard dirt bikes with special screws in the tire treads. Sharp heads on the screws allow riders to hit fast straightaway speeds and turn without sliding into snowbanks. Racers claim the traction is actually better on ice than on dirt or pavement.