“If you are going into rougher terrain and you still want to use an end dump, typically you will shorten it up so there is not so much up in the air,” Badinger adds. The shorter trailer also allows greater maneuverability on the jobsite.
Another issue you may want to investigate is insurance costs. “We have heard with live--bottom trailers -- and I am sure it plays over to belly dumps and possibly side dumps, too -- that your insurance is typically less than with an end dump,” says Badinger.
An increasingly popular alternative to end dump trailers is the side dump. “There is a gravitation toward side dumps in a lot of markets in the Midwest,” says Badinger. “They are a little more versatile when it comes to hauling product like rip rap.”
Side dump trailers are also more stable than end dumps during the dump cycle. “One key factor in side dumps is the low center of gravity as you offload either to the left or to the right,” says Andy Anderson, vice president -- marketing, Thurston Mfg. “The center of gravity actually gets lower as you offload.”
Therefore, trailer length is not as much of an issue in terms of stability.
Unlike a belly dump trailer, the side dump doesn’t drag its axles over the material being unloaded. “It dumps outside the frameline,” says Anderson. This means the operator doesn’t have to get out of the truck to make sure the tops of the trailer axles are clean. “With the bottom dump, after you get off the pile, you have to get out and make sure you don’t have any rock on the axle,” says Anderson. “You don’t want that rock picking off somebody’s windshield.”
A bottom dump trailer leaves a ribbon of processed material. “It is one of the lightest and least maintenance intensive,” says Badinger. “You are not dealing with any hydraulics. All you are dealing with is two air cylinders.”
The light weight is a definite advantage. “If you are hauling sand, gravel and asphalt to a project, the lighter you are, the more you can haul,” says Badinger. To address this demand, Trail King recently introduced the Ultra Light belly dump (10,000 lbs.), which uses a stronger grade steel with thinner walls and structures to save weight.
Belly dumps are also very stable. “Your center of gravity is always fairly low,” says Badinger.
Live--bottom trailers are also gaining market share from end dumps. “In the Eastern part of the United States, and the Northeast specifically, the live--bottom trailers have a niche because you are not lifting the end dump in the air when you are carrying the heavier loads allowed over there,” says Badinger. “It’s a finish product trailer.”
“Asphalt and low--slump concrete are where controlled horizontal discharge trailers shine,” says Smith.
These trailers actually help improve paving quality. “You are not segregating your materials because you are not lifting your trailer up in the air,” says Badinger. “When they slide, materials will tumble. The bigger rocks tumble faster and they separate. In a live bottom, you just meter it out.
“You don’t deal with lifting the box up into the air and you don’t have to worry about overhead obstructions like a bridge or power lines,” he adds.
Compare Cycle Times
For many contractors, the total turn time is a critical measurement as it determines how many trips you can make in a day. “The folks that are bidding contracts here in the traditional Midwest or the Mountain West measure total turn time -- time to haul, dump and return,” says Anderson.
The cycle time to dump the trailer and return to the transport position has a major impact on total turn time. The shorter the haul distance, the more the cycle time will impact the total time required. “If the average haul distance is two to 10 miles, then dumping in 30 seconds is much more important than dumping in a couple of minutes,” explains Anderson.
End dump trailers usually take a couple of minutes to complete a dump cycle. “You have to find a good spot, back up, make sure you are level, take it up in the air, dump and go,” explains Badinger.