Hydrostatic drives keep coming in smaller packages, such as on this 23-hp Vermeer RT200, and its 15-hp counterpart, the RT100.
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Over the past 10 years, the utility industry has been so distracted by the rapidly developing directional-boring business that it may have been easy to overlook steady improvements made in small trenchers. Now that the economy has reined in utilities' unbridled enthusiasm for trenchless methods, trencher manufacturers have reacted by bringing some fairly substantial changes to the trencher drives in less-than-100-horsepower machines.
"The choice between boring and trenching is a little more economically driven now," says Carl Hoffman, general manager of Sun Communications in Westfield, Ind. "It had been customer driven for a while—utilities were boring because it made good public relations. Now, if it's cheaper to trench, they'll trench and restore."
The most aggressive, recent changes in trencher specifications involve the drive system that turns the chain. The secret to trencher productivity and durability is matching the chain speed to the soil conditions and ground speed. Most ground drives are hydrostatic or hydraulic, both of which offer infinitely variable ground speeds.
To improve control over chain speed, manufacturers have employed just about every conceivable power-transmission option to the trencher drive. The industry started with mechanical drives to transmit power from the engine to the trencher chain, but hydrostatic drives have gained in popularity. Of the 53 models of chain trenchers currently available with under-100-hp engines, 19 are hydrostatic. As with the ground drive, infinitely variable speed with fairly constant power output is the main advantage. It allows the operator to refine chain speed to match conditions.
Hydrostatics, and even less-expensive hydraulic drives, are more difficult to damage when the trencher bar is in the ground. And the flexibility of transmitting drive power through hydraulic fluid offers the ability to build machines with sliding offsets, so the trencher bar can shift left or right to reach out near the machine's edge.
Hydraulic drives, of course, use a pump and motor to transmit power, but they use an open-loop system where hydraulic fluid drains to the reservoir after leaving the motor. Hydrostatics typically have a pressurized drain circuit that goes from the motor directly back to the pump. Hydrostats tend to be more efficient than hydraulics working at higher pressures over time. But very few small trenchers are expected to do high-production work over long shifts. Twelve of those 53 trencher models still have hydraulic drives.
For a long time, hydrostats have seemed like overkill for smaller pedestrian trenchers—more system, and more money, than an under-20-hp trencher needs. But manufacturers of hydraulic pumps and motors have invested heavily in developing hydrostatics. Few of them still offer hydraulic-drive systems big enough for trenchers approaching 100 horsepower. And as component manufacturers have become more competitive with smaller hydrostatic systems, Burkeen and Vermeer have introduced pedestrian trenchers down into the 15-hp range with hydrostatic drives.
In extreme conditions, some of the first generation of hydrostatic trencher drives had problems with overheating and maintaining productivity. Today's trencher product managers admit that they've accumulated invaluable experience with hydrostats, and the manufacturers are showing practical wisdom in the designs of cooling and filtration systems. Hydrostatic drives have gained productivity thanks to larger reservoirs, better radiators and more efficient cooling fans.
But a persistent bias against hydrostats by some of the hardest-working trencher owners drew a significant technology challenge into the under-100-hp trencher class a little more than a year ago. Ditch Witch introduced the RT70 and RT90 with optional powershift transmissions. The powershift is an adaptation of the clutchless mechanical transmission common in tractors, which allows the operator to change gears without interrupting power.
Ditch Witch customers have purchased the powershift machines at slightly lower cost than their hydrostatic counterparts, which is certainly attractive. But the technology has drawn the attention of some trencher users because it offers a mechanical drive link with a choice of two speeds. The operator can adjust chain speed without interrupting digging power. Ditch Witch stands alone in applying powershift technology to chain drives.
One of the reasons other trencher manufacturers have not rushed to compete with mechanical-drive trenchers may be the major influence that rental companies wield. Since 1999, the number of rented rubber-tired trenchers at work in the United States has grown 26 percent, according to the Construction Equipment Universe Study. In 2003, 19 percent of all rubber-tired trenchers in the field are rented.
Rental-fleet owners like hydrostatic and hydraulic machines because, for them, filters are easier to maintain than clutches and belt or chain tensions. Turnaround time in the rental yard is reduced. With pump manufacturers improving the performance and affordability of small hydrostatic systems, and a major customer group like the rental houses expecting fluid power, a great deal of trencher manufacturers' resources for trencher development are clearly going to hydraulic and hydrostatic drives.
Pedestrian trenchers are the most popular configurations because there are so many applications for a small trencher. Plumbing and electrical services, irrigation systems, communications and cable television, even some larger utility work can be done most economically with a trencher that can squeeze into small spaces. The rise of rental work has brought simplified, color-coded controls so that people who don't use trenchers every day can quickly learn to operate them. It's a development that has probably been good for the whole market.
Small trenchers have continued to grow up, as manufacturers respond to customer demand for improved durability by putting more horses under the hood. Look for an acceleration of this trend as they comply with the Environmental Protection Agency's Tier II emissions requirements. One example: When Vermeer replaced the 44-hp V3550A rider in June with the RT450, frame size hardly changed but the RT450 comes with a Tier-II-compliant engine rated at 50 horsepower.
At the ICUEE show in September, Ditch Witch introduced an option for its larger utility machines that provides the operator a digital readout of how deep the machine is trenching. The electronic system—called the Trench-Depth Meter (TDM)—uses a version of bore-locating technology. Its memory can be integrated into mapping systems that are being used to keep an accurate underground inventory of installed lines.
More common options tend to be less high-tech. The vast majority of riding trenchers have a backfill blade. About half of the large riders being sold today go out the door with a backhoe and four-wheel steer. Four-wheel steer has been available for quite a long time, but demand has risen rapidly of late as a result of congested workplaces and increasingly delicate installations amid other underground lines. For similar reasons, sliding offset trenchers are also growing in popularity.
Options make small trenchers versatile, and the array of drive options makes them productive. Expect technology in this smaller category of trenchers to continue to improve, as the long-run installations of telecom industry are finishing up. There's plenty of last-mile trench to be cut—installations where there are not expensive improved surfaces to refinish—in lengths perfectly suited for tough, under-100-hp trenchers.
Average Trencher Costs
| |
Base price |
Hourly cost* |
| 18 hp - 35 hp |
$24,500 |
$32 |
| 36 hp - 60 hp |
$39,900 |
$45 |
| 61 hp - 94 hp |
$59,800 |
$59 |
*Combined ownership and operating expensesSource: "Contractors' Equipment Cost Guide," published by EquipmentWatch - 800/669-3282.Basic Specifications: Pedestrian Chain Trenchers |
| Manufacturer/Model |
Gross Horsepower |
Operating Weight (lbs.) |
Max. Trench Depth |
Trench Width Range |
Chain Drive |
| Specifications shown here are based on information provided by manufacturers and Spec Check, and are given for comparison only. Specifications are subject to change. For more information on specific models, visit Construction Equipment's website at www.ConstructionEquipment.com. |
| Of 23 pedestrian trencher models available, three are hydrostatic and eight have hydraulic trencher drives. The smallest hydrostatic machines are the Vermeer RT100 at 15 horsepower and Burkeen's B-16 at 16 horsepower. Ditch Witch recently introduced its hydraulic 1330 to compete with Barreto's hydraulic 13-hp units. |
| Ground Hog T-4 |
5 |
230 |
1' 0" |
3.0"– 3.5" |
Mechanical |
| Vermeer RT60 |
6 |
270 |
1' 0" |
3"– 3" |
Mechanical |
| Parsons T80 |
8 |
640 |
2' 6" |
4"– 6" |
Mechanical |
| Ditch Witch 1030 |
11 |
780 |
2' 6" |
4.3"– 6" |
Mechanical |
| Parsons T120 |
11 |
640 |
3' 0" |
4"– 6" |
Mechanical |
| Vermeer V1150 |
11 |
850 |
2' 6" |
4"– 6" |
Mechanical |
| Burkeen B-13 |
12 |
820 |
3' 0" |
4"– 6" |
Mechanical |
| Barreto 1318-H |
13 |
860 |
2' 6" |
4"– 6" |
Hydraulic |
| Barreto 1324D |
13 |
1,025 |
3' 0" |
4"– 6" |
Hydraulic |
| Barreto 1324D4 |
13 |
1,075 |
3' 0" |
4"– 6" |
Hydraulic |
| Case 60 |
13 |
720 |
3' 0" |
4"– 6" |
Mechanical |
| Ditch Witch 1230 |
13 |
780 |
3' 0" |
4.3"– 6" |
Mechanical |
| Ditch Witch 1330 |
13 |
920 |
3' 0" |
4.3"– 6" |
Hydraulic |
| Parsons T130 |
13 |
700 |
3' 0" |
4"– 6" |
Mechanical |
| Vermeer V1350 |
13 |
850 |
3' 0" |
4"– 6" |
Mechanical |
| Vermeer RT100 |
15 |
880 |
3' 0" |
4"– 6" |
Hydrostatic |
| Barreto 1624D |
16 |
1,025 |
3' 0" |
4"– 6" |
Hydraulic |
| Barreto 1624D4 |
16 |
1,075 |
3' 0" |
4"– 6" |
Hydraulic |
| Burkeen B-16 |
16 |
1,290 |
4' 0" |
4"– 6" |
Hydrostatic |
| Ditch Witch 1820 |
18 |
1,300 |
4' 0" |
3.3"– 16" |
Mechanical |
| Vermeer RT200 |
23 |
1,485 |
4' 0" |
4"– 8" |
Hydrostatic |
| Vermeer LM25 |
25 |
2,570 |
3' 0" |
4"– 6" |
Hydraulic |
| Vermeer LM42 |
45 |
3,335 |
3' 6" |
4"– 6" |
Hydraulic |
Basic Specifications: Ride-On Chain Trenchers (Less than 100 horsepower) |
| Manufacturer/Model |
Gross Horsepower |
Operating Weight (lbs.) |
Max. Trench Depth |
Trench Width Range |
Chain Drive |
| Specifications shown here are based on information provided by manufacturers and Spec Check, and are given for comparison only. Specifications are subject to change. For more information on specific models, visit Construction Equipment's website at www.ConstructionEquipment.com |
| Vermeer still offers riders with hydraulic and mechanical chain drives up to 85 horsepower, but the over-50-horsepower market is awash in hydrostatic drives (10 of the 17 models available are hydrostats). Parsons' recent decision to stop making a riding trencher reduced the competition by three. |
| Case TF300B |
18.5 |
2,315 |
3' 9" |
4"– 16" |
Mechanical |
| Burkeen B-25 |
25 |
2,290 |
3' 0" |
4"– 6" |
Hydraulic |
| Ditch Witch HT25 |
25 |
4,080 |
3' 3" |
4"– 16" |
Mechanical |
| Case 360 |
32 |
3,906 |
5' 0" |
6"– 12" |
Mechanical |
| Case 460 |
37 |
5,660 |
5' 0" |
6"– 16" |
Hydrostatic |
| Case Maxi-Sneaker C |
37 |
2,346 |
3' 0" |
4"– 6" |
Hydraulic |
| Ditch Witch 3610 |
45 |
3,765 |
5' 0" |
0"– 16" |
Mechanical |
| Ditch Witch 3700 |
45 |
5,425 |
4' 4" |
6"– 12" |
Hydrostatic |
| Vermeer V4150A |
45.3 |
5,640 |
5' 0" |
5"– 16" |
Hydrostatic |
| Burkeen B-36B |
49.5 |
4,600 |
5' 0" |
6"– 12" |
Hydrostatic |
| Ditch Witch 3700CD |
50 |
4,200 |
5' 3" |
6"– 12" |
Hydrostatic |
| Vermeer RT450 |
50 |
3,350 |
5' 0" |
5"– 12" |
Hydrostatic |
| Case 560 |
51 |
7,000 |
6' 0" |
6"– 16" |
Hydrostatic |
| Ditch Witch 5700 |
57 |
n/a |
5' 2" |
6"– 12" |
Hydrostatic |
| Vermeer V5750 |
60 |
6,300 |
5' 0" |
6"– 16" |
Hydrostatic |
| Vermeer V5800 |
60 |
13,565 |
5' 0" |
7"– 16" |
Mechanical |
| Case 660 |
67 |
11,219 |
6' 0" |
6"– 16" |
Hydrostatic |
| Vermeer V6500 |
67 |
8,570 |
5' 0" |
6"– 18" |
Mechanical |
| Ditch Witch RT70 Hydrostatic |
70 |
n/a |
8' 1" |
24"– 24" |
Hydrostatic |
| Ditch Witch RT70 Powershift |
70 |
10,770 |
8' 1" |
24"– 24" |
Powershift |
| Vermeer RT700 |
70 |
10,050 |
6' 0" |
6"– 16" |
Hydraulic |
| Vermeer Flextrak 75 |
79 |
8,700 |
5' 0" |
6"– 12" |
Hydrostatic |
| Vermeer V8100 |
80 |
12,395 |
5' 0" |
6"– 18" |
Mechanical |
| Ditch Witch RT90 Hydrostatic |
85 |
n/a |
8' 1" |
24"– 24" |
Hydrostatic |
| Ditch Witch RT90 Powershift |
85 |
11,830 |
8' 1" |
24"– 24" |
Powershift |
| Vermeer RT850 |
85 |
10,050 |
6' 0" |
6"– 16" |
Hydraulic |
| Vermeer V8550A |
90 |
11,783 |
5' 0" |
6"– 18" |
Hydrostatic |
| Case 960 |
99 |
16,000 |
7' 0" |
7"– 18" |
Hydrostatic |
