Posted for information from the IMBA website
The evolution of mountain biking goes beyond the development of ultra-technical trails – it also includes a resurgence in dirt jumping and bike parks. Here are 18 key ideas to help you design and build bike parks that are fun, durable and likely to earn approval from a land manager.
The focus here is on building dirt jump parks, but the tips apply to designing a freeride park, or any combination of dirt jumps and freeride challenges.
If the volume information that follows seems overwhelming, keep in mind that building a bike park is a ton of work – you’ll want to have thought through the whole process well before you’re knee-deep in mud. Build it right and you’ll ride it forever.
- Get Permission and Build a Partnership
Always get permission and land-use permits before you begin building jumps. Most unauthorized jumps are quickly bulldozed, and their existence can jeopardize future projects. Forming a strong partnership with the land manager will create a situation in which everyone wins. The best way to get a jump park built is to take a well-planned, business-like approach. Detailed tips on how to write a proposal can be found in IMBA’s book Trail Solutions.
- Form a Team and Seek Input
Get in touch with every rider you know and form a working group. According to Judd de Vall, a pro rider and IMBA trailbuilder who has built several jump parks, “Involving a wide range of people gives everyone ownership and ensures the project’s future. The best jump parks often result from a blend of ideas. Don’t forget to include kids and BMX riders!”
- Select a Location
Securing a piece of property is often the most challenging element in the process. An ideal location will offer a permanent home for the jumps, be centrally located and connected to other trails, include trees that offer shade and interest, have good drainage, and include a nearby water source.
- Secure a Permanent Water Source
Convenient access to water is necessary for jump construction and maintenance. The best scenario is pressurized underground plumbing with several strategically located faucets. Don’t neglect this critical element! George Matthews from the Friends of North Saanich Dirt Jump Park says, “Water is critical to the quality of the park and to keep volunteers involved. Without water the jumps are too hard to work and people loose interest.”
- Develop a Risk Management Plan
A thoughtfully written Risk Management Plan is the best way to ensure safety measures are developed and implemented. At a minimum, your plan should include the steps to take in an emergency, an overview of signs and perhaps fences that delineate the boundaries, a description of the inspection and maintenance plan, and info about insurance.
- Develop an Effective Signage System
It is important to develop a comprehensive signage system for your jump park. Signs should be placed at the entrance and other key locations. The main sign should describe safety guidelines, helmet rules, risk warnings, a “Use at Your Own Risk” message, responsible riding tips, emergency contact information and more.
- Acquire Insurance
Most public jump parks will require an insurance policy to shield landowners, officials and volunteers from liability claims that might result after a jumping injury occurs. Some land managers already have insurance policies in place for their skate parks and other recreation facilities: these can often be modified to include a jump park.
- Develop a Scheduled Inspection and Maintenance Program
Jumps require routine upkeep. You must be committed to inspecting and maintaining a park before you build one. Inevitability, damage occurs from people walking on the jumps, riding when it is wet, missing landings, skidding, etc. It is important to develop a stewardship ethic among riders that encourages everyone to repair their divots, groom the jumps regularly and keep the park clean. A written log should be kept to ensure jumps and surrounding area are being looked after regularly and maintenance work is documented. This step is key to reducing liability.
- Design the Jumps
Designing a park with good flow takes skill, vision and creativity. Be sure to enlist experienced jumpers. Plan a safe and predictable layout that still provides an exciting and challenging park. Features could include all types of jumps, including table-tops, gaps, step-ups, step-downs and hips. Street features like rails and wall rides are popular, as are freeride stunts like ladder bridges, skinnys, teeters and drops. Aim for linking features so riders flow immediately from one to the next. Ideally, a rider will not have to brake between jumps. Allow plenty of clear, smooth space to the sides of jumps for missed landings. Include a corridor for riders to return to the starting ramp without riding too close to the jumps.
Once you decide on all of the park’s features, you’ll have to create a schematic drawing that shows the entire property, including dimensions, elevations and drainage. Get the plan approved before beginning construction.
- Include Jumps for Everyone
It’s important to build jump lines that offer a wide variety of challenge, from easy rollers to big jumps. A diversity of lines will allow riders to build their skills gradually and will create a park that is fun for all abilities. Typically, jump lines are arranged side-by-side in increasing difficulty, all starting at a common roll-in hill and traveling in the same direction. Offer regularly scheduled skills clinics that teach riding techniques and responsible jump use. “Jumping is all about progression,” says pro rider and jump builder Jay Hoots. “Improving skills and moving up to the next level is what gets riders stoked.”
- Table-Tops or Gaps?
Table-tops are jumps with a flat top that allow a rider to roll over the jump without being forced to catch air. Gap jumps, also called double jumps, utilize takeoff and landing ramps with a gap or chasm in between. Riders must launch from the takeoff and clear the gap to reach the landing. Table-tops are essential for beginner and lower-intermediate lines. Because there is no gap to clear, table-tops are less risky than gaps. But expert riders often seek the challenge of gap jumps, and table-tops require far, far more dirt than gap jumps. Semi table-tops, or camel jumps, are a blend of the two styles. They don’t have a flat top, but a rider can still roll over them if desired. No matter which style you choose, build your lines consistently. If one jump in the line is a table-top, than all the jumps in that line should be table-tops. Don’t surprise riders with a gap jump in the middle of an otherwise rollable line.
- Measurements and Geometry
Jump height should be 2-3 feet for beginner jumps – add a foot or two as difficulty increases. Jump length will be 4-7 feet from the lip to the landing for beginner jumps, and will increase with difficulty. Jump length must be paired with jump height and takeoff angle so riders will hit the landing. Jump width should be 5 feet or greater – landing ramps should be even wider to allow for flubbed landings.
The distance between the landing of one jump and takeoff of the next should be about 22-26 feet. The angle of takeoff and landing ramps on beginner jumps doesn’t need to be curved or “transitioned.” More difficult lines can have transitioned ramps that curve upwards and launch the rider smoothly into the air. Only the largest jumps require transitioned landings. “Takeoff transitions are an art and play an important part in the feel of a park. Take your time and work gradually to craft smooth, predictable lips,” says Hoots.
- Develop a Construction Plan
Reach agreement on how the jumps will be built, how long the construction phase will take, how much it will cost, and who will provide the money, dirt, equipment and labor. Taking your time in the planning stages will help prevent crises once building gets underway.
- Get Good Dirt
The best soil for the surface of dirt jumps is screened loam with a fairly high clay content. Loam is ideal because it packs firmly and is easy to shape. You should be able form a ball by squeezing a handful of moist dirt. Clods that are difficult to break indicate too much clay content. Depending on the amount of rainfall in your area, the foundation for the jumps may need to be built from a more porous dirt that allows water to drain through, such as gravel or sandy loam. High-quality dirt can be reserved for takeoffs and landings. If using dirt from the site or lower quality dirt, you can save lots of work by using a screen or mechanical sifter to remove rocks. Kris Gray, one of the riders behind a new jump park in Park City, says, “We had plenty of donated dirt from local construction projects, but we burned out our volunteers by asking them to pick rocks by hand. Renting a screen and bucket loader to remove rocks is a wise investment that will ensure volunteers have energy for the finish work.”
- Grade the Site for Drainage
Visit the location during a heavy rain to learn where water flows and pools. “Drainage is everything!” says Hoots. “If possible, the site should have a gentle slope perpendicular to the jump lines to ensure water will drain away.” Depressions that trap water must be filled, especially low spots between jumps. A well-drained jump park will be ready to ride sooner after rain or snow, and require less maintenance. Never ride on muddy jumps, and post signs asking others not to ride until the soil is dry.
- Build and Compact the Jumps (Finally!)
Using mechanized equipment to haul dirt and build jumps is a huge time-saver. Whether building by machine or hand, however, the steps are the same:
- Form rough jumps to within a couple feet of desired size, then sculpt to within six-inches of the final shape.
- Use a rake to remove all surface rocks and break clumps.
- Lightly water jump surface – just enough to moisten dirt but not so much that water runs off or creates mud. Use a rake to blend moisture evenly throughout the top few inches of dirt. A thick layer of moist dirt will create a well-compacted jump surface.
- Rake to within a couple inches of desired shape, and begin compacting the dirt.
- . When the jump is no longer sticky, use hand tools and bicycles to pack the riding surface. Lips and landings must be smooth and consistent, so take your time to pack each surface thoroughly.
- Encourage Stewardship
Involving riders from the beginning will translate to essential ongoing maintenance. Says de Vall, “If you ride, you must dig. Because dirt jumps take so much time to build and are so fragile, riders must embrace and pass on this key jumping code.” Pro rider Timo Pritzel says, “The key to a good riding spot is a tight group of friends that are motivated to build.”
- Learn from BMX and Skateboarding
In addition to these tips, consider the advice offered by BMX and skateboarding organizations. They’ve been building killer skate parks and BMX tracks since the ’70s.
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.