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Fifteen Tips for Building Excellent Downhill Trails

Input from experienced downhill riders is essential
Input from experienced downhill riders is essential to creating a good downhill trail. Location: A-Line, Whistler, British Columbia.

Prevent water from flowing down the trail
Prevent water from flowing down the trail by incorporating frequent grade reversals. This trail runs straight down the fall line, channels water, and is deeply eroded.

Grade reversals are a critical - and often overlooked
Grade reversals are a critical - and often overlooked - element of sustainable trail design.

he trail can go straight down the fall line without causing erosion if it is located on solid rock
The trail can go straight down the fall line without causing erosion if it is located on solid rock. Location: Whistler, British Columbia.

 Drop-offs are a key feature
Drop-offs are a key feature to include on downhill trails.

Design your trail so that it runs through as much rock as possible
Design your trail so that it runs through as much rock as possible. Location: Tamarack, Idaho

Rock armoring is the best way to ensure the trail will withstand the abuse of water and riders
Rock armoring is the best way to ensure the trail will withstand the abuse of water and riders. Location: Canmore, Alberta

This armored berm will withstand years of abuse
This armored berm will withstand years of abuse. Location: CBC Trail, British Columbia.

Downhill riding is all about rhythm and flow. As they descend the trail, downhillers go as fast as possible by finding the best lines and riding smoothly. Advanced riders tend to ride faster lines - those that require a higher level of strength, agility, and reaction.

A downhill trail should be technical, with features and lines that challenge riders of all abilities. Here are some ideas to help you create trails that are exhilarating for downhillers.

 

1. Involve Downhillers.

Input from downhill riders is essential to creating a good downhill trail, and the design and construction of the trail should be directed, at least in part, by a downhiller. The ideal rider/consultant has experience building downhill trails and understands the fundamentals of sustainable trail and feature construction. This person should also have peer respect and the ability to ride tough trails confidently and smoothly. He or she must be able to plan and build a trail that will be fun and rideable for the full range of intended users.

2. Determine the Trail Placement.

We define downhill trails as single-use, one-way trails with technical trail features designed for the sport of downhill mountain biking. These trails should not be shared with other users unless those users know and accept that mountain bikers will be riding the trail at high speeds. Downhill trails should be separated from trails designed for other users in order to avoid conflict. Building two downhill trails-one beginner/intermediate and one expert/pro-will reduce conflict between riders of different abilities and speeds and provide each group with a more enjoyable experience.

3. Incorporate Vertical Drop.

An ideal downhill trail will have a vertical drop of least 1,000 feet. An epic trail will have more than 2,000 feet. The more vertical drop the better! However, even locations without big mountains can have great downhill trails if the design is creative and fun.

4. Plan for Shuttling.

Downhill trails are almost always located on mountains that have summit access via automobile or ski lift. Unfortunately, one of the most common problems associated with downhilling is the social impact of automobile shuttling on the outside community. The increased traffic on and parking alongside public roads - not to mention truckloads of bikers doing laps from dawn to dusk - may upset locals. This conflict often results in trail closures; so if you predict shuttling will occur at your trail, take steps to ensure that it won't anger residents and other trail users.

There should be convenient, proper parking and turn-around areas at the top and bottom of your trail. If you are choosing a location for a new trail, be sure the nearby shuttle route does not go through a populated or busy area. Downhillers often drive their own cars to the trailhead and then pile into a truck to shuttle their runs. In some cases, a racing team will use a van with a trailer, making it possible to shuttle up to 15 riders at a time. Your parking area should be able to accommodate these large vehicles and trailers.

If a nearby road will be used for shuttling, aim to create only one entrance and one exit for the entire downhill trail system. This will help minimize conflict with other road users by concentrating mountain bikers and their vehicles at two locations - the top and bottom.

5. Minimize Trail Intersections.

Minimize the number of other trails that crisscross a downhill trail. Given the speed of downhill riders, it is important that downhill trails feature elements that slow riders before they arrive at intersections and meet other visitors. Just be sure the slowing devices blend with the trail style and are not too abrupt or potentially dangerous. A series of two or three insloped turns, also known as berms, work well to slow riders smoothly and in a fun manner. Each turn should point the rider slightly back up hill and lead into a somewhat tighter turn ending at a yield sign. Avoid using excessively restrictive devices to corral or slow riders, as these elements can be dangerous and riders may collide with them. Make sure that sightlines at intersections allow plenty of time for riders and other visitors to anticipate these crossings.

6. Include Open and Flowing Sections.

These wider, faster sections allow riders to choose from a variety of lines, especially through turn entrances and exits. They also test a rider's ability to keep his or her bike stable and balanced at high speeds. Some racecourses are as wide as 50 feet. These sections are often rough and fast (up to 50 miles per hour). While ski resorts have historically supported the use of broad corridors for downhill racing, securing permission to build and maintain them in public parks and forests is difficult.

7. Include Tight and Technical Sections.

These slower sections challenge a rider's ability to turn quickly, negotiate obstacles, and float through difficult terrain. These sections can include drop-offs and other technical trail features.

8. Design Flow Transitions.

A good downhill trail will alternate between tight and technical and open and flowing trail, as both styles of trail test riders' abilities to choose the best line and then ride that line smoothly. It is important to design smooth transitions between sections of different flow. Using insloped turns when approaching tighter sections will slow riders gradually, reduce skidding, and improve the transition. Putting a steep section directly after a technical section will allow riders to accelerate quickly and easily and to enjoy the entirety of an open and flowing section.

9. Use Grade Reversals.

Keep in mind that the trail shouldn't be downhill the entire way. As with all trails, frequent grader reversals are essential to ensure drainage. Design short uphill sections of about 20 to 100 feet in length every several hundred feet to allow water to exit the trail and to challenge the riders to maintain their momentum. You can use jumps and rollers to create short grade reversals, or you can design a slight, uphill turn in the trail to make a longer reversal. Longer uphills should be preceded by a fast section, allowing the rider to hit the uphill with plenty of momentum.

10. Rock to the Rock.

Design your trail so that it runs through as much rock as possible. Rock adds great technical challenge, is highly durable, and usually requires less maintenance than other natural tread surfaces. Rock is especially useful in building steeps and drop-offs. Rock also enables you to add trail features such as wide, off-camber corners, which normally would erode. See more tips for working with rock.

11. Build Insloped Turns (Berms).

Insloped turns, usually called berms by mountain bikers, help riders carry momentum through corners. Berms keep riders on the trail and, perhaps most importantly, they are fun to ride. Berms must be placed in the right spot in the trail corridor and be the correct height, length, and radius. Berms should naturally draw the rider in and should shoot the rider back out of the corner at a greater speed. If a berm doesn't feel right, don't hesitate to change its height, length, or radius so that it does its job. Berms have the potential to trap water, so it is essential to utilize grade reversals to improve drainage before and after the corner.

Berms can be as short as 1 foot and as tall as you want to go. The faster a rider enters the corner, the taller, longer, and wider the berm should be. Berms are often built too far from the turn's apex, which can cause riders to make a tighter turn in order to cut the corner. Move the entire berm toward the apex of the turn if this happens, as the fastest line through a corner should use the berm.

12. Include Jumps.

The first priority when building jumps is to create smooth flow through the approach, take-off, air, and landing. Each jump should be clearly visible so riders can choose whether to bypass the jump or hit it, based on a split-second decision. Riders must be able to hit jumps at full speed without being thrown at takeoff or overshooting the landing. If a takeoff ramp is too steep, a rider's rear wheel will be bucked when hitting the jump at full speed.

It is important to make gradual transitions between the approach, the jump face, and the jump lip, and landings should be long, wide, and gradual to allow for a soft touchdown. Jumps can be step-ups, step-downs, or level. Jumps on downhill courses range in length from about 10 to 60 feet, and jump lips can be anywhere from 2 to 10 feet tall. Inexperienced riders often build dangerous jumps. Take the time to find a seasoned rider and trailbuilder to help you construct this type of feature!

13. Include Drop-offs.

Drop-offs are some of the most fun and challenging natural features on a downhill trail. Like jumps, they must be visible and clearly marked to allow riders to smoothly pass around or off the drop - even when approaching at high speed. The approach should be a little slower than the actual take-off so that riders don't have to hit their brakes right at the top. The landing area should be wide and sloped downhill, and it should be carefully located to allow riders to hit the drop at full speed without overshooting the landing zone.

14. Provide Optional Lines.

There should always be an easier, alternate route around a technical feature or jump. On advanced trails, the technical feature can be located on the main line, with an easier option to the side. On intermediate or beginner routes, technical trail features should be outside the main trail flow. Optional lines can potentially be in the same corridor as the main trail; for example, a drop-off could vary in height from one side of the trail to the other. Both lines should be easy to see and should blend with the trail's flow, as riders will be moving fast.

15. Minimize Man-Made Structures.

Ladder bridges, teeter-totters, and other freeriding stunts are not recommended on downhill trails. They are freeride features and do not accommodate high speeds. While a ladder bridge might be used to control erosion on a very steep section of trail, it should not be challenging in its width, and should be positioned so that faster riders can jump over it. There have been occasions when racecourse designers placed logs across a trail in order to increase that trail's difficulty level. This is dangerous and can injure riders.

Don't Forget Maintenance!

Downhill trails are generally steeper than shared-use, recreational trails. Because of this, and because of greater forces and changes in speeds, downhill trails erode more quickly and require more tread maintenance and drainage structures than other trails.

The suggestions offered in this and other IMBA trailbuilding articles do not constitute a standard, specification, or regulation. Trailbuilders and landowners are responsible for the safety of their own trails and facilities. Freeriding and dirt jumping are high-risk activities that can result in serious injuries. IMBA's goal is to help land managers and volunteers manage these risks by sharing information.

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