When Ben's front tire slid off the trail, I hit the brakes. From a standstill, I watched as he flew over the handlebars and belly-flopped onto the packed dirt.

Mountain biking can be a harsh sport. And Minnesota's Sawtooth Mountains can bring out its wildest conditions. At Lutsen Mountains resort, more than 30 miles of mountain biking trails wind from four distinct summits. Ski hills in the winter, they become a haven for cyclists in the warm months.

The dirt single-track, gravel and rock slab trails drop through the hills and ride up valleys that tower above the Poplar River on the North Shore of Lake Superior.

I last rode Lutsen on a hot day in early July. Ben's crash was one of many our small group saw and experienced that day -- although none were serious.

The gondola tramway and Mystery Mountain chairlift did most of the uphill work for us, and we rode dozens of miles down the mountain trails. Slick downhills, winding forest trails, jumps, mud and endless scenery kept us smiling from morning until late afternoon.

Crisscrossing the ski slopes, Lutsen's mountain-biking trails travel near lift towers, chalets and deep into the woods. Some of the trails stretch across the mountain's wide faces and allow bikers to cruise downhill for more than 5 miles. We rode downhill nonstop on one of these long trails for more than 45 minutes.

This much vertical time is rare in Minnesota. While most Midwestern hills roll with the terrain, the Sawtooths jut up from Lake Superior and rise more than 1,500 feet above the shoreline.

The steep terrain combined with the rich green northern forest and deep blue Lake Superior water create some of the state's most stunning views. From the top of Lutsen's tallest peak, the Sawtooths stretch out of sight to the north and west and Superior blends with the sky on the eastern horizon.

On the bike, the view is much more myopic. Roots, rocks, bumps, ruts and other obstacles demand constant concentration and quick reactions. The forest becomes a blur in your peripheral vision as the curves and dips in the trail hold your full attention.

Even with this strict concentration, the bike can still get away from you. And that's when you hit the dirt.

--Stephen Regenold (verticaljones@hotmail.com) is a Minneapolis-based freelance writer.