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How Denver got a dedicated downhill MTB trail

A short drive from Denver, Colorado, Floyd Hill's Sluice trail is a gnarly, downhill-only, purpose-built mountain bike trail. We went to the Session Series enduro MTB race to see what this singletrack is all about. And, we talked to the folks from COMBA to learn how this trail was built.

Written by: Spencer Powlison

Published on:

Posted in:MTB

For a split second, my front wheel lost traction on the steepest section of a massive rock slab. As the bolt of adrenaline zapped me, the Maxxis rubber miraculously hooked up, and I recovered. While I averted a major disaster in my first go at Team Evergreen’s Session enduro series, my performance was entirely unremarkable.

However, the Sluice trail itself, scary rock slab and all, is truly remarkable. I was racing enduro on a purpose-built, downhill-only mountain bike trail, just a short drive up the hill from Denver. How many fast-growing metro areas, with populations counted in the millions, can lay claim to that sort of rad riding opportunity?
Sending a drop-off at the Session Enduro MTB race
Not many trails on public open space will give you the opportunity to get this rad. Photo: Eddie Clark

Okay, yeah I see you Vancouver, but hear me out: The Floyd Hill Open Space, home to the Sluice trail is a huge achievement. To get to this point, it took a lot of bureaucratic wrangling, planning, thousands of volunteer hours, and of course, money.

How Floyd Hill's Sluice trail was born

In 2017, the Clear Creek County Open Space Commission partnered with a handful of land trust organizations to purchase a property on Floyd Hill, expanding what it already owned. At that point, the vision for this open space project was unclear. Fortunately, the County soon formed a steering committee and brought a number of partners to the table.

Colorado Mountain Bike Association (COMBA) was one of those stakeholders, and from the early days, it played a key role in getting the Sluice trail approved and constructed.

“We helped put together the money that was needed for [professional trailbuilders], sat on the steering committee, and were a part of developing the master plan,” said Gary Moore, COMBA’s executive director. “That’s the point where we usually have the most luck at getting things like hiker-only segments, biker-only segments. Modern trail management like designated use, separation by speed, and directional trails.”
Gary Moore COMBA executive director
Gary Moore, executive director of the Colorado Mountain Bike Association, was a major part of the planning, fundraising, and trailbuilding process at Floyd Hill.

You might think that public land managers would be leery of downhill-only mountain bike trails, but surprisingly, Moore and COMBA didn’t meet much resistance. The mountain bike contingent had a few things working in its favor. First, COMBA got involved early in the planning process, so they could weigh in on what riders were looking for. Second, Floyd Hill was essentially a blank slate, so there was no pushback from existing trail users. And finally, COMBA’s plan for a downhill-only trail just kind of made sense.

“We had the opportunity to build in this logical flow,” said Moore, referring to the climbing trails and downhill-only trail. “You don’t need a bunch of rules and signs and people getting angry at each other. If we can just naturally make the trails work in a way that we want to, people just do it. You don’t have people ‘salmoning,’ because it’s just naturally not the best experience.

“This trail, as we got the plan together for it to be directional, downhill, bike-only, that was our first win.”

But that was only the beginning of a two-year process to create the area’s first-ever downhill-only, mountain bike-specific trail.

The trailbuilding process

Once the steering committee agreed to build a downhill mountain bike trail, the hard work began. Moore broke it down into a five-step process to go from a high-level plan to tires on dirt (or rock slab, as it were).

As tempting as it would be to run out into the mountains and start digging, the first step happens at a desk, on a computer, with a topo map. They start with the basics: Who is this trail for and where do we want to put it? Looking at the map, planners from Contour Logic and ERO Resources figured out the general corridor where they’d build. Fifty-foot cliffs or sensitive archaeological sites? Avoid those. Great views or cool terrain? Head thatta-way!

The second step is to essentially ground-truth it all. According to Moore, seven is the lucky number when making bushwacking expeditions through a property like Floyd Hill. After those seven trips through the bush, you can confirm the general zone where the trail will go.

Next, the trail design itself becomes a lot more concrete in the third step. A builder will go in with little pin flags to mark the specific course of the trail-to-be.

Then the fun begins. Step four brings in the builders with their machines and tools who will cut it in and bring the idea to life. And a lot of times, they’ll make it even better than the planners imagined.

“Flowride Concepts came in and blew my mind. Some of the really cool alt lines are way over my head,” Moore said. “They ride the gnarliest stuff. When you give them a chance like this to build what you would ride, as a builder they’re like, ‘Yeah!’ They’re still thanking us for having them make that trail.”
Building the Sluice trail at Floyd Hill
Professional trailbuilders brought the Sluice trail's vision to life, and made it a whole lot gnarlier than anyone had even dreamed it could be. Photo courtesy Gary Moore.

Finally, in the last step of the process, the builders and planners ride the trail and monitor its wear to tweak and adjust little details to improve the ride.

The process is detail-oriented, exhaustive, and a bit expensive. Moore estimates it cost about $110,000 to build the Sluice alone. But given that it handles 1,500 riders per week on average, it has to be dialed to handle the traffic.

The Sluice trail is done, but never really done

Floyd Hill and the Sluice trail feel like a finished product when you roll up to the line of Team Evergreen’s Session Series race, chip timing and all. However, there’s a ton of behind-the-scenes upkeep to keep this, often the most popular trail in the county, running smooth, er, I guess rough.

COMBA organizes two volunteer trailwork days every week, one before the midweek race, and one after, to make repairs and touch things up. To date, they've spent more than 1,000 volunteer hours maintaining the Sluice trail. Plus, COMBA is working on building a connection between Floyd Hill and Jefferson County’s popular Mayhem Gulch trail.

As for myself, I made a lot of little mistakes in my run down the 1.3-mile track, but my biggest error was not pre-riding the Sluice beforehand. In part, it would have made the race a lot less scary. But above all, the trail is super-fun, and unlike anything else you’ll find outside of a downhill bike park, let alone on open space land, a short drive from Denver.

If you want to get involved with COMBA at Floyd Hill or any of the other trails it supports (and there are 400 miles worth of trails!) visit

Visit our Denver resource page for info on Denver-area bike shops, trails, events & more.