The Missoula Technology and Development Center (MTDC) was asked to find a good way to maintain a 40-mile (64-k) motorcycle and all-terrain-vehicle (ATV) trail on the Francis Marion National Forest in coastal South Carolina. Heavy use leaves a washboard surface that progresses to mounds and gullies several feet across. These are called "whoop-de-doos," and trail users find them both unpleasant and unsafe (Figure 1).
Figure 1-Evaluating equipment that effectively cuts
the mounds and fills the depressions on washboard trails is what this
report is about. This trail has been partly graded to
remove the whoop-de-doos.
The problem of whoop-de-doos is not unique to this trail in the sandy coastal plain of South Carolina. We began the project by asking off-highway vehicle (OHV) trail managers throughout the Forest Service how they were maintaining their OHV trails. Several National Forests had developed prototype lightweight graders that could be towed behind ATV's, effectively removing whoop-de-doos with routine maintenance. MTDC worked with two of these Forests to further improve and evaluate these prototypes, tested them in South Carolina, and looked to the open market for similar equipment.
This report focuses on three pieces of equipment tested in South Carolina: a modified trail rock rake suggested by Cam Lockwood on the Angeles National Forest, CA; a trail drag designed by Dick Dufourd and Kim Larsen for use on the Deschutes National Forest, OR; and an Ultra Light Terrain Grader manufactured by The Shop Industrial, Lively, Ontario, Canada.
We found all three pieces of equipment suitable for OHV trails in sandy or pumice soils. They can all be pulled with ATV's. OHV trails are wider, typically at least 4 feet (1.2 m), than hiking or equestrian trails, and have fewer curves. All of the equipment would have functioned better on trails had the equipment been narrower.
The trail rock rake and the Ultra Light Terrain Grader worked exceptionally well on narrow roads like those found in camp-grounds, and for grading parking lots. They are a realistic and affordable alternative to full-sized graders for such applications.
In less detail, this report includes other ways that OHV trail managers are maintaining their trails. These include the TrailPlane developed by Mil Lill and used by the Cycle Conservation Club of Michigan; various drags, harrows, cultipackers, and rollers; and other techniques field personnel told us about.
In heavier or rocky soils, on steep trails, and where rutting and erosion is severe, heavier equipment is needed. In these situations, small crawler dozers such as the SWECO 480, small tracked excavators, or small utility tractors do the trick. We give this equipment only cursory coverage in this report. To learn more about this heavier equipment, refer to a 1996 report from the San Dimas Technology and Development Center, 9623-1207-SDTDC. See Sources and Contacts to find out how to order a copy. The San Dimas Center is also producing a video about using mechanized trail equipment. It should be completed in 1999.
This project's objective was to identify equipment that could effectively grade motorcycle and ATV trails in sandy soils. Grooming would smooth out the bumps, flatten mounded berms, and eliminate ruts.
The 40-mile- (64-k)-long Wambaw Cycle Trail is on the Francis Marion National Forest, north of Charleston, SC. It receives heavy use by both motorcyclists and ATV enthusiasts. The topography is flat, the soil is sandy, and the trail winds through mostly pine forest. Curves are tight, designed to appeal to motorcyclists (Figure 2).
Figure 2-Typical section of the Wambaw Cycle Trail.
The trail was designed for motorcycles, but ATV's are also allowed.
Cam Lockwood, trail coordinator for the Angeles National Forest in southern California, proposed that MTDC modify a flexible-tooth landscaping rake manufactured by York Modern Company. Lockwood wanted hydraulic controls that would swivel the rake's blade from side to side, raise and lower the wheels for the proper amount of cutting action, and help transport the rake over pavement, rocks, or other obstructions.
We fabricated two prototypes, one for the Angeles National Forest and one for testing on the Francis Marion National Forest (Figure 3). We started with a York Model TA-26, added a hydraulic snowplow power pack, two hydraulic cylinders, a heavy-duty steel battery box, and a gel battery designed to withstand rough treatment. We modified the trailer hitch to accept a 1 and seven-eighths-inch (48-mm) ball on an ATV.
Figure 3-MTDC's trail rake begins with a York landscaping rake, with hydraulics
for swiveling the rake and for raising and lowering the wheels.
The controls raised and lowered the wheels to set the depth of cutting. Adjusting the blade's angle was easy and positive with the hydraulic setup (Figure 4). The hydraulics failed because of a design flaw in the power pack. After talking with the manufacturer, we corrected the problem.
Figure 4-Control switch for the hydraulic power pack
angles the rake and raises and lowers the wheels.
The wheels can be adjusted either to "float" with the terrain, or to be held at different heights, depending on the degree of soil cutting desired. The maximum amount of cutting action is obtained in the float mode.
The rake worked quite well in our limited field tests. The flexible spring-steel tines cut the mounds and filled the depressions in the trail. With the spaces between tines, not as much material was sidecast. To a greater degree than the other two graders tested, the rake pulled berm material back into the middle of the trail (Figure 5), especially with two passes down the trail.
Figure 5-With two passes, the trail rake could
pull in berm material from both sides to the center of the
trail or road. Here, the scraping blade is being used.
For a more positive removal of surface material, the scraping blade is an option (Figure 6). We preferred the action of the rake without the blade, because the rake seemed to roll rocks better than the blade, and there was less bouncing and chance of getting hung up on rocks.
Figure 6-The scraping blade
flips up out of the way when not in use.
In a third prototype, we have installed ripper teeth into the scraping blade to help loosen compacted tread material, making it easier to rake on subsequent passes when the blade and teeth are raised (Figure 7).
Figure 7-Ripper teeth attached to the scraping blade in an untested
third prototype. The ends of the 6-foot (1.8-m) rake were hinged
(center) to narrow the rake for trails and widen it for roads.
The 6-foot (1.8-m) rake was too wide to maneuver around some of the corners on the Wambaw Cycle Trail. Cam Lockwood thought the width was about right for trails on the Angeles National Forest. The York Rake is also available in a 5-foot (1.5-m) width. This width would have worked better on narrow trails. To keep the benefit of a longer width for road work while allowing the blade to be shortened for the narrow trails, we have hinged each side of the blade in our third prototype.
Parts for the trail rake cost about $2,250. MTDC shop labor added another $1,150, for a total prototype cost of about $3,400.
See Sources and Contacts to order engineering construction drawings of the trail rake: MTDC-968, Trail Rake. Brian Vachowski at MTDC can provide additional information regarding alternatives for fabrication, including possible fabrication by MTDC for Forest Service units, depending on MTDC's shop workload.
After experimenting with several different designs over the years, longtime Deschutes National Forest employees Dick Dufourd and Kim Larsen designed a trail drag that grades tread material to the center of the trail. Dick Dufourd reports that it has been working extremely well.
MTDC fabricated another prototype, a wider version of the Deschutes Trail Drag, and tested it in South Carolina. The principal difference was that the MTDC drag was 34 inches (86 cm) wide (Figure 8). For trail work, we found it was a mistake to widen the drag from its original 28 inches (71 cm). The extra width made it more difficult to wind around trees and curves in the trail. This, of course, would be more of a problem on some trails than on others.
Figure 8-MTDC's version of the Deschutes Trail Drag.
The original was only 28 inches (71 cm) wide, a better width for trails than this
one, which is 34 inches (86 cm) wide. Angled blades on the drag provide a
cutting action, pulling in loose tread material to the center of the
trail. A straight blade on the rear, and a beavertail metal grate
behind the rear wheels, smooth out the graded material.
An electric actuator, controlled by the ATV operator, raises and lowers the wheels to control the amount of soil cutting.
In South Carolina, the Deschutes Drag effectively flattened the washboarded whoop-de-doos. However, the actuator that operates the wheels failed. We were unable to make the number of passes down the trail needed to smooth it completely. The Deschutes National Forest, working in pumice soil, reports that their version of the drag works fine in removing whoop-de-doos, and that usually about three to four passes are needed to grade the trail smooth. They, too, reported actuator problems. Our engineering plans now specify a heavy-duty actuator that should correct the problem.
If you would like to build the Deschutes Trail Drag, contact MTDC and ask for Engineering Drawing MTDC-969, Deschutes Trail Drag. Call Brian Vachowski to talk about fabrication questions.
Parts for the Deschutes Trail Drag cost about $1,050. Labor is estimated at $1,400, for a total cost of $2,450 for our prototype.Ultra Light Terrain Grader
A commercially available product, the Terra Master ULTG 12-04 Ultra Light Terrain Grader, was the third piece of equipment we evaluated in South Carolina. It is manufactured by The Shop Industrial, Lively, Ontario, Canada (Figure 9).
Figure 9-The Ultra Light Terrain Grader has manually
adjustable rear wheels and an electronically operated front lift.
The Ultra Light Terrain Grader is based on the successful design of The Shop Industrial's Mogul Master line of snowmobile trail groomers (Figure 10). Its long planing length and grader blades produce a smooth and very flat surface after several passes down the trail. Each rear wheel is independently adjusted manually for the degree of cutting desired, as well as to adjust the slope of the finished grade. Usually, the wheels have to be adjusted only infrequently. Outslope or crowning is possible with this machine.
Figure 10-An electric actuator on the Ultra Light Terrain Grader lifts
the front end to the desired level, setting the depth. Four angled
serrated grader blades plus a rear straight grader blade
pull soil to the center of the trail.
The Ultra Light Trail Grader is designed to be pulled with a four-wheel drive ATV or similar vehicle. The grader's cutting depth and load are controlled by the operator. A handlebar control switch activates an electric actuator that is mounted between the hitch and main frame of the grader.
The Shop Industrial markets the Ultra Light Terrain Grader for use on ATV and dirt bike trails, bicycle paths, roads, parking lots, and driveways, for landscaping, or for any application where the terrain needs to have a smooth, flat finish.
Width: 4 feet 3 inches (1.3 m)
Length: 14 feet (4.3 m)
Height: 25 inches (64 cm)
Weight: 450 pounds (204 kg)
Four heat-treated serrated grader blades
One rear heat-treated straight grader blade
Eight-inch (20-cm) stroke, 12-volt electric actuator
Front hitch with 1 and seven-eighths-inch (48-mm) trailer ball receiver
Control switch and wiring harness
Dual rear wheels with manual "top link" adjusters.
The 1998 price for the Ultra Light Terrain Grader was $2,750 (U.S.), FOB Lively, Ontario, Canada. Customs' and brokers' fees are included in the price. The Ultra Light Terrain Grader is the only grader in The Shop Industrial's line that can be pulled with an ATV. The company has two other models 6 feet 4 inches (1.9 m) wide, and 8 feet 4 inches (2.5 m) wide that can be pulled with a pickup truck. They are designed for road and lane grading. See Sources and Contacts for information about contacting The Shop Industrial.
The Ultra Light Terrain Grader (Figure 11) was too wide and long to negotiate many of the curves in this particular trail without widening the trail or hitting trailside trees. We limited the evaluation to a section of trail with gradual curves and fewer trees close to it (Figure 12). The Shop Industrial representatives said they would be willing to custom build shorter and narrower versions of the Ultra Light Terrain Grader that might be better suited for trail work.
Figure 11-Due to its length and width, the Ultra
Light Terrain Grader had a hard time negotiating corners.
Figure 12-In the South Carolina demonstration, the Ultra Light
Terrain Grader was very effective in removing whoop-de-doos after several
passes down the trail.
On roads and parking lots, the Ultra Light Terrain Grader was very effective (Figure 13). Where larger graders are not available when you need them, or on narrow roads, drive-ways, and in campgrounds, the Ultra Light Terrain Grader may be a good choice.
Summary of South Carolina Field Evaluations
Figure 13-The Ultra Light Terrain Grader was
designed for roads and parking lots. It works best there.
All three graders effectively graded parts of the Wambaw Cycle Trail. None of the graders completed the task in a single pass. Graders required three or four passes to completely remove whoop-de-doos.
All three graders were too wide for this particular trail, and would be too wide for most motorcycle trails and some ATV trails in forested settings. The equipment is also too wide for hiking and equestrian trails. The problem was that the graders had a hard time negotiating corners and avoiding trailside trees. The graders tended to track the inside corner of turns, but the tread material that needed to be brought back onto the trail was bermed along the outside edge. The graders worked best on straight sections of trail and on trails with gradual curves.
Frequent curves are designed into these trails to differentiate them from roads and to make them fun to ride. Straightening or widening trails to make them easier to maintain could reduce user satisfaction. Trails would become B-O-R-I-N-G.
Although the graders are designed to pull tread material back onto the trail from the edges, none of the three graders could reach more than a few inches beyond the edges of the trail to pull in bermed material. The Trail Rake was a little better than the others. Depending on the amount of tread that had been eroded or cast off the trail, the graded trailbed was lower than surrounding terrain. Although this wasn't a problem in the porous, sandy soil of coastal South Carolina, creating such a trench in the heavier soils or in erosion-prone areas would cause water to run down the trail or to pool.
The best solution for severely eroded trails is to bring in additional clean, structural fill material (from the berms or somewhere else), raising the tread surface to grade. Effective drainage structures would need to be installed to move water off the trail. You will want to assess whether such a solution, with regular maintenance, is going to be permanent. If not, consider closing and restoring that trail segment if a better route can be found.
In soft soils, it's best to keep users off the trail after grooming. The longer, the better. One day is better than none, and a week is better yet. "Setting up" depends on soil moisture. Some of the loops on the South Carolina cycle trail are closed for an entire season to allow rainfall to "set up" the trail, forming a hard, compacted surface.ATV Power Requirements
Pulling these graders is tough on ATV's, especially when rocks or roots are encountered. We noticed a direct correlation between happiness and horsepower when it comes to trail grading. More horsepower means fewer overheated engines, less cussing, more work getting done.
For the South Carolina evaluations, The Shop Industrial brought a 500-cc Polaris Sportsman to test their grader (Figure 14).
Figure 14-The trail rake and Ultra Light Terrain Grader
worked great on campground roads and parking lots.
At the East Fort Rock OHV areas on the Deschutes National Forest, 500-cc Polaris machines are also used. They are four stroke, four-wheel drive, and liquid cooled. The vehicles are always operated in low 4-by-4 range. The graders perform best at slow speeds, 5 to 7 mph (8 to 11 k/hr)-they cut better and bounce less. Appendix A includes an equipment checklist, and Appendix B shows the trail-grooming procedures for the East Fort Rock OHV trails.
For more information, visit the US Department of Transportation's OHV Trail and Road Grading Equipment page