WOODBURY, Minn. -- Racing in brutal cold, down snow-packed hills in Minnesota is just like riding a bike for Martha Flynn. Her tires are just thicker.

"Sometimes we call each other fatty," said Flynn, referring to riders who use bikes with thick tires.

Martha Flynn CBS News

At a recent race near Minneapolis, Flynn maneuvered her bike through a tight, icy track where tree trunks are the bumpers.

The bikes can cost upwards of $6,000. It costs $2,500 alone for the wheels and five-inch-wide tires built to grip snow and ice.

"You just look down at that giant tire and it just makes you smile," said Flynn.

The race went for 22 miles along a downright terrifying course. It's held on what's typically the coldest week of the year.

"I've raced before with the starting temp at minus 10," said Flynn, who would never trade a ride in the cold for an afternoon by a fire. "You have to get out. It's beautiful."

A drone provides an aerial view of the bike race CBS News

If you see Flynn as a thrill-seeker, Garrett Macy is something else. He thinks two wheels are just too easy so he rides on one wheel instead, but admits he falls dozens of times a ride.

Garrett Macy rides his unicycle alongside correspondent Jamie Yuccas CBS News

"Generally you just wipe off the snow because you land on your feet," said Macy. "We actually call that an unplanned dismount."

After an hour and half of racing this year's winner was decided by half a second. But for most riders where they finished really wasn't the point. Because in this Tour de Freeze, the fun is in the trip.