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“When I analyze a site and start planning a trail system, I try to use the steep side slopes for climbing trails or shared-use segments,” said Joey Klein, veteran trail designer and builder with IMBA’s Trail Solutions. “More gently angled side slopes, from five to, at most, 40 percent, are the best match for either entry-level singletrack or gravity, flow and downhill trails.”
“It’s counterintuitive that gently angled hillsides are the best places to build both beginner trails and gravity trails,” continues Klein. “But when we are trying to boost riders into the air we do not need super-steep grades. To create big turns, fun jumps and happy landings we want a consistent, moderate trail grade matched with enough side slope for proper water drainage.”
Maintainable Or Sustainable?
There’s no doubt that bike-optimized trails featuring in-sloped tread, abundant rollers and high berms are a hoot to ride. When a new gravity or flow trail opens to the public, the response is usually rampant enthusiasm and a big increase in bike traffic—with all ability levels taking to the trail to experience something new and different. This often leads to erosion, particularly because inexperienced riders need to refine their braking, cornering and jumping techniques.
“There’s nothing inherently more or less sustainable about lifted and tilted trails compared to traditional singletrack,” says Klein. “But if a trail gets super popular because it’s so fun to ride, and at the same time riders are sliding through turns and constantly hitting their brakes, there’s definitely going to be some significant soil loss. I tell local groups to expect this, especially in the first few seasons, and to be prepared to perform a relatively high volume of maintenance, including patching berms and smoothing out the trail tread.”
In this sense, bike-optimized trails can be thought of as maintainable, rather than self-sustaining. (Of course, all trails require some degree of regular maintenance). But the trade-offs are often well worth the increased load on volunteer maintenance crews. In New Mexico, IMBA's chapter the Santa Fe Fat Tire Society recently built a new flow trail called Hustle and Flow—with assistance from Klein—that is earning positive feedback in the community.
“The trail required a huge effort and pushed our volunteer trail crews to their limits,” said Tim Fowler, the chapter president. “We probably underestimated the time required to build all the berms and jumps. Still, there are no regrets. The end result is fantastic—it was especially gratifying to see high school-aged riders showing up to help build the features, and getting excited about a new style of trail.”
Teddy Jaramillo and Lewis Starvrowsky, both 16 years old, are two of the young riders who joined the work crews. “I’m super stoked to see more people getting into flow trails and having them available in our community,” said Jaramillo, who is a four-time state champion in BMX and the reigning national champion for the 15-18 age group in category 3 downhill racing. “I will definitely join our local IMBA chapter in Santa Fe and help with future trail projects.”