Take the Colorado Trail — one of our state’s treasures with its high alpine vistas, wildflower meadows, steep ascents and meandering mountain streams — and throw in sleep deprivation, thunderstorms, hail, biking at night, wildlife encounters and the very real potential for hallucinations from exhaustion and you have the Colorado Trail Race.

It’s a mountain bike race from Durango to Denver along all 485 miles of the Colorado Trail. If that’s not wild enough, there’s somewhere around 70,000 feet of elevation gain, with long sections above tree line.

Even in the biking community this race seems a little off the radar, to a point where getting information about it was starting to feel like finding out about Fight Club.

People say they’ve heard of it, know something about it, but details are scarce.

“It’s a bunch of hardcore guys ready to suffer,” said Kristopher Carlsted, president of the Summit Fat Tire Society.

The cast of characters attracted to that kind of punishment is few in number. This year’s race is expected to have 60 to 65 competitors, and odds are close to half of them are unlikely to finish.

Perhaps aptly described as a guerilla or grass-roots bike race, the event, started in 2007, is free to compete in.

“It’s definitely not what you would consider an organized event,” said Joey Ernst, a race competitor and owner of Velorution Cycles in Durango.

Mike Zobbe of the Summit Fat Tire Society described it as sort of an “underground” race. And yet, it’s possible to follow competitors’ progress online through Spot GPS tracking.

This year’s race starts Sunday, July 21, at 4 a.m. outside of Ernst’s bike shop.

It’s the first year that the majority of riders will start in Durango and not Denver.

They idea to reverse directions was fairly arbitrary, Ernst said.

He described the organizers thought process as, “Well, hey, what if we do it backwards.”

The course record, set last year, is a remarkable 3 days, 23 hours and 38 minutes, set by Jefe Branham.

Other racers said he accomplished the feat by barely sleeping and riding through most of the nights.

While it apparently worked for Branham, a number of racers have described having hallucinations or hearing voices as a result of exhaustion from over-exertion.

“In the middle of the woods I heard Bob Dylan,” said Ernst about an experience riding at night. He thought it may have come from an RV parked at some unseen campground. “I think it was real but I couldn’t say for sure,” he said.

Ernst also told of another nocturnal encounter riding with a light.

“I came across some sets of eyes looking back at me,” he said. They stopped him in his tracks. After an initial fright, he discovered that the eyes belonged to some free-range cattle.

Others have encountered more pressing dangers, like hail and lightning storms above the tree line.

So what lures riders to such a punishing undertaking?

“I really enjoy long rides,” said Ernst. “It’s not because it’s always fun; it’s because it’s a challenge.

He went on to describe the appeal of the range of emotions. “There’s amazing highs and the lowest of lows.”

Earnst finished in 11th place, with a time of 5 days, 14 hours and 44 minutes, when he raced in 2011.

For Jeff Rank of Breckenridge, this year’s ride is part tribute. He will be scattering some of the ashes of his friend Jeff Lindenblatt along the trail. Lindenblatt, an avid biker, passed away earlier this year in an avalanche. He’d raced with Rank in previous years.

This will be his third time racing for Rank. He finished one of his previous two attempts. Flight arrangements forced him to quit his first race within 80 miles of the finish.

As for strategy, Ernst said, “It’s like thy say, slow and steady truly wins the race. Take every day as it comes.”

For those who participate it’s as much about finishing as anything.

“When you’re done it feels like a great accomplishment,” said Rank. “No one knows what you went through except other riders.”

Follow online through the CTR Race Tracker link at http://www.climbingdreams.net/ctr/.