Pit & Quarry, February 2010

H A U L I N G TRUCK SPECS I f youre in the market for a haul truck its important to do your homework Unlike some other vocations dump truck specifications are regionalized What works in one area of the country might not work in another Your first piece of homework Find out the length and weight regulations in your state and take advantage of the weight laws to maximize payload Some states mostly in the West require compliance with the Federal Bridge Formula This will determine how the axles are set up and spaced A Bridge Formula truck will tend to be longer to spread the weight said Brian Lindgren vocational market sales director for Kenworth Truck Co in Kirkland Wash You may need to have lift axles but there are different rules on how much load you can add with lift axles And some states dont allow pusher axles Your dealer should know the rules and regulations In states where you dont need to comply with the Bridge Formula you can spec trucks shorter and heavier making them more maneuverable on jobsites Loading hauling questions Some key questions that need to be answered concern the loads that you expect to haul For example you will need a different chassis spec when hauling bulk loads such as asphalt sand or gravel than you would if you hauled mostly demolition debris If youre planning on visiting a lot of demolition sites you will need to have the body and suspension beefed up to handle the pounding it will take from the large pieces going in the dump body Your body supplier will have input on this The hauling question relates to the environment or roads you are operating in Are you going to spend a lot of time on rough jobsites or will most of the hauling be long distances on smooth gravel and sealed roads If you will be going off road a lot into rough terrain youll need a suspension that is heavier duty and has more articulation Lindgren said But if youll be hauling longer distances youll need to consider the trade off between the ease of dumping and the ability to haul more load per trip For example a transfer dump will allow you to haul more with one driver but it will take longer to unload Double bottom trailers carry a lot of payload too but youre limited on where you can drop the load It is more difficult to dump gravel into a hole for a swimming pool for instance with bottom dumps Drivetrain One of the big mistakes many people make with dump truck engines is they spec too much power Lindgren said You should get just enough horsepower to do the job Generally 350 to 400 hp is plenty for most solo unit applications Extra horsepower just uses more fuel puts more strain on the rest of the drivetrain and adds cost up front If you go with a smaller 13 liter block you save around 400 lbs over a 15 liter block he said The transmission should have a large ratio range You need a low enough gear to get out of a hilly jobsite and high enough top gear to attain decent highway speeds The Eaton Kenworth Truck Co offers advice on specifying an on off road dump truck EDITED BY DARREN CONSTANTINO Take note Rear axle ratios should be matched with the transmission so that engine speed is around 1600 rpm at highway speed 48 PIT QUARRY February 2010 www pitandquarry com