Tough Trails Should Be Rock-Solid

As mountain bikers become more skilled and equipment improves, many seek increasingly difficult trails to test their skills. For many folks, difficult means steep routes, but steep trails can create big erosion problems. Anyone can get behind the seat and lock both brakes, taking the trail with them. But to preserve the land and insure future trail access for mountain biking, new trails must be routed gradually across the slope and must generally avoid the fall line. While some mountain bikers will at first consider these contour trails too tame, elements can be included in the design to enhance technical challenge while also ensuring long-term sustainability.

One effective technique is to use rock to add challenge and "harden" the trail. Here are five ways to include rock in trail design:

Steeps. Locate solid rock slabs or faces where a trail can run straight down the fall line without causing erosion. San Antonio riders are challenged by "The Wall" - a 15-foot high rock face that falls away at a 90% grade. The Wall is a favorite challenge for local riders yet remains erosion free. When designing a feature like this into a trail, use care to ensure the outrun is also durable rock or make sure the trail flows freely away to prevent heavy braking. Use a natural grade reversal or dip above the steep to keep water off the trail.

A North Carolina Slickrock Steep. Click for bigger picture.

Rock gardens. Route your trail over and through existing rocky areas. West Virginia's Tea Creek Mountain Trail has a rock garden that everyone tries to clean but rarely does. This rocky section batters bikes and is also appealing to hikers and equestrians. People expect rocks in nature and won't avoid them if they seem natural. The key is that no matter how difficult the rock section might be, it still must be the easiest route through that area. This gives folks no other choice but to stay on the trail, avoiding trail-widening or shortcuts.

A nice East Coast Rock Garden. Click for bigger picture.

Rock chokes. A series of boulders staggered on either side of the trail can provide a narrow choke or slot that enhances the ride. This strategy can slow users and add challenge. Make sure the narrowing flows naturally with the trail - otherwise people will find it annoying instead of interesting, and may create a new route around it.

A narrow rock chute and drop. Click for bigger picture.	Rock choke with stone pitching. Click for bigger picture.

Armoring. Use large rocks to "pave" a trail and prevent erosion. Trailbuilders in soggy Wales are forced to armor entire pathways with stone to escape year-round mud. Large, ominous rocks are buried in the tread, making the trail interesting and dry. When using rock for armoring try to isolate boulders that take two or three people to move. This ensures that the rock will remain in place for a long time. Bury at least a third of the rock in the ground: take time to place it permanently and make it appear natural. Experiment with different rock placements and mimic natural outcroppings.

Very old armored trail. Click for bigger picture.

Drop-offs. Utilize natural ledges or construct short drop-offs with rock. This addition on a contour can challenge riders both ascending and descending. A six-inch-to-a-foot drop is appropriate for most users. Make sure the drop-offs fit with the overall flow of the trail. Use them in bike-length series in an area where riders won't be taken by surprise. This spacing also makes it possible to climb, as well as descend. Transitions are important: a tight turn following a drop would cause riders to skid or shoot off the trail. Higher drops can employ two possible lines on the same trail - one difficult and one easier using a ramp or chock stone.

Rock Drop and Steep. Click for bigger picture.	Rock Drop. Click for bigger picture.

Finally, make sure to get permission from your local land manager or owner before starting any trailwork. Rock on!