Access Action: Creating a public gravity park

Words by Frank Maguire, photos and illustrations by Jon Pratt and Shea Ferrell of Flowline Trail Design

The most iconic images of mountain biking often involve a just-right moment of wheels arcing through the air, body and bike fluid in their escape of gravity’s pull, the rider willing the bike onward and upward toward what we all imagine will be a smooth re-entry. Those images make us reminisce about days spent playing in a driveway or alleyway, where we leaned a piece of three-quarter-inch plywood on a cinderblock and launched ourselves at the makeshift ramp.

Or maybe you went to a corner of the yard, just out of Mom’s sight and started digging, knowing that if you dug deep enough, you’d have enough dirt to make some sweet jumps. Those momentary childhood expressions of freedom often came to an abrupt end when Dad came home and put an end to the “mess you made.”

Now that we’re adults, it’s time to think about what it will take to recreate those play spots and to to build something that will be worthy of our efforts. At IMBA, we sometimes refer to such trails as “bulldozer-proof.” The reward for doing things the right way is being able to rest assured that what we build will be long-lasting and can become true community assets.

The first step in this whole process is to recognize what it is you are asking for. Bike-specific features such as jump lines, pump tracks, and skills parks go beyond what mountain bikers have typically been allowed to build on public lands for the past 20 years. To avoid confusion in conversations with land managers, it’s better to talk about “features” or even “facilities,” than just trails.

Whereas natural surface trails can serve a variety of needs and users, bike features really only serve the needs of one user group, and probably a fairly narrow slice of the biking community at that. It is likely that such exclusivity will make it nearly impossible to put features into existing trail systems, and that’s probably for the best. Features require a different type of maintenance and planning, and should not be confused with any skills you and your club have developed through building singletrack.

The good news is that because these features are an entirely different animal, they might fit better into areas you hadn’t considered approaching for trails. County and municipal parks with developed recreation areas for traditional sports may be the best place to start. As opposed to multi-use facilities,

These types of parks are used to dealing with individual user-groups asking for specific facilities. For example, if your community has a disc golf course, it would be worth looking at how it came to be and use that as a blueprint. Skate parks are an even bet- ter example because it is likely that the city’s legal department had to get involved and determined that risk can be minimized (more on this later).

Learning how to speak the language of a facilities manager will help you walk them through your dream trail in a way that doesn’t immediately scare them or put them off. Incorporating the following ideas into your plan will help make that dream a reality.

What follows is a list of some of the different considerations and ideas that should be part of any plan. You may notice that I do not discuss how to shape jumps and pack berms. One reason is that there are several professional trail building resources available, but also because the fine art of feature construction deserves an article all its own. The focus here is providing an understanding of how to begin to develop the design concepts for the features you want.

The entrance: It is critical to make sure that the only people who get on your trail are the ones who have the desire and skill to be there. This is accomplished in two ways: signage and qualifiers. It’s best if the entrance is not in the normal flow of any other trail traffic, but rather acts as a gathering spot before people roll in. Funneling riders to the signage and the qualifier will help them transition into the different experience.

Signage: The language of a good sign is more than a list of “Thou shalt nots!” and should focus on making the trail experience understandable. It should encourage people to walk the trail first. Explain the skills that are needed and the types of equipment and protection that are mandatory or strongly encouraged. Include some sort of way-finding as well as directions to the nearest emergency room. The language should be developed with the cooperation of a local risk management official.

The Qualifier: Think of this as the clown’s arm at the amusement park, the one that says, “You must be this tall to ride.” The qualifier is a mandatory feature that sets the tone for the ride. It should be an example of what the rest of the trail will be like in terms of features and the ability level required to ride them. And unlike other features on the trail, this one has no ride-around option. Good examples of this would be a skinny boardwalk or a rock drop. Placing rocks, or even a fence, to guide riders onto the qualifier helps emphasize the gateway feel.

The Approach: Placement is critical to the success of your features. Each feature needs to blend into the flow of the trail and not be an abrupt transition. By placing a grade reversal a few bike lengths before the feature you allow several things to happen. First, the surface leading up to the feature does not become a series of brake bumps, causing control issues. The grade reversal acts as a natural speed check and adds to the rhythm of the ride; think of it as going up to get down. Secondly, this speed check allows riders to square up or opt to take the ride-around option. The setup area should be between two and four bike lengths following the grade reversal, depending on the entrance speed.

Fall zone and ceiling height: Each feature needs to be placed with a bailout in mind. Good features will require practice and repetition to get right, so the inevitable fall needs to be planned for. Your fall zone should be at gradual grade and free of rocks and stumps in a one-to-two-bike length arc. You should also clear the trail ceiling (Yes, there is a ceiling.) eight to 10 feet above you when standing on top of the feature. Even on drops, clearing the ceiling prevents riders from focusing on something above them during the approach, when they need to focus on where they’re headed.

The landing: Transition on landing is key to how the feature feels in the overall flow of the trail. Abrupt transitions or landing on flat ground will sap momentum out of the ride and make it more likely that someone will get hurt. The landing zone should be twice whatever the approach area is, allowing for recovery before the next section of trail.

If you expect the trail to be heavily used, the surface of the landing might need to be armored with rock or turf block pavers to withstand regular impact. Make sure that the armoring is consistent and fairly uniform. The idea isn’t to create a rock garden in these sections, but to help the surface tolerate abuse. It’s also a good idea to place another grade reversal after the landing to let the flow return.

Materials and methods: Do you want to emulate the beautiful ladder bridges that photograph so well in British Columbia? There is a reason cedar is the construction material of choice. Abundant as debris from logging or wind damage, cedar is incredibly rot resistant and its grain provides a nice texture for traction. If you need to build out of wood, it is best to use untreated and non-dimensional lumber, such as rough cut white oak, locust, or cedar. The shortcoming of wood is that it needs to have a more rigorous inspection routine and can be expensive to replace. Are the fasteners holding up? Has anything become loose?

Do any planks need to be replaced? Building with rock is often preferable to wood, as it is aesthetically more natural in the landscape, and when done properly should hold up to years of abuse. Stone can sometimes be sourced locally and is more durable, but the skills to work with rock take time to acquire. Turf block pavers are great for hardening surfaces and are relatively easy to install, but can be very difficult to get on location. Any decision on what materials to use should be made in conjunction with the park manager.

Risk management: If you are dealing with a developed recreation park, chances are the park will have a staff person charged with assessing risk and management strategies. It is critical that this person understands what it is you are look- ing to build, and that you explain every step of the construction process. They should work with you to document the planning steps you have taken and how you plan to maintain the features, including developing a maintenance schedule. Risk management is all about trying to plan for the eventual accident. In all activities, the participant assumes some risk, but it is up to you as the trail builder to make sure your features don’t increase that risk. The final step in any risk management plan is to have liability insurance, because even if you do everything right, you might still need to prove it someday.

About the images

These illustrations were the product of in-house photography that was combined with illustrations from Flowline trail Design. They are a collaboration of designers, artists, builders and riders drawn together by the common drive to create progressive and sustainable riding destinations. Check out what they can do at




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