Feature article: Watch your weight

Max Kvidera | January 01, 2010

Daily or weekly inspections to check welds, bolts and rivets and for deformed parts are advised, says Dan Giles, director of engineering for commercial trailers at Fontaine Trailer. Verifying that load securement points are in good repair is also wise. “Those joints will show signs of stress, deformation of the bolts that may be coming undone, or hairline cracks in welds,” Giles says.

Owner-operator Fred Jones, who is leased to Davis Transport, says he periodically checks bolts on his 4-year-old aluminum trailer. “I go underneath with a wrench and tighten all the nuts,” he says. “Lock nuts have a tendency not to come loose, but it’s a good idea to keep everything tight.”

You also want to check your trailer alignment to facilitate even tire wear. Wabash’s Ehrlich says you can visually spot from the rear of the trailer or looking out the mirror some alignment problems – such as dog tracking, where the back end is trailing to one side.

“More difficult to see is where you have one wheel pointing slightly in a different direction,” he says. “You don’t have a way to correct that other than bending the axle.” It’s very difficult to do, he adds, and axle replacement is generally the solution. ATA’s Technology and Maintenance Council has a recommended practice guideline for trailer axle alignment (RP 708-A) and one for the tractor-trailer as a system (RP 642).

Owner-operator Gordon Bow, who runs Mortgage Hill Trucking under his own authority, says he checks tires weekly for wear and proper pressure. If a trailer is out of alignment, tires wear unevenly and cup, he says. “You can tell a lot about axle alignment just by running your hand over the tread.”

Bow checks brakes regularly and installs dust shields all around to keep out dirt. He inspects wheel bearings to ensure they’re not leaking and lubricates them according to manufacturer recommendations. He checks the air suspension’s bushings and shock absorbers and replaces the shocks at least annually.

During inspections, Cole suggests washing off residue from chemicals used to melt snow and ice. “They will eat up trailer components and the wiring system,” he says.

Bow recommends avoiding jackrabbit starts and hard stops, hitting corners too fast and exceeding speed limits. “Those are going to take a toll on your trailer,” he says.

Loading equipment, such as forklifts and pallet jacks, can put a strain on trailer floors and walls.

Loading Flatbeds

The key to loading flatbeds is sticking to the trailer’s middle. Most manufacturers start with two main beams in the center and put supporting pieces at right angles. Most cargo should cover the main beams, Giles says. Manufacturers do not specify front or back of the trailer for placement of most loads.

“The main concern with flatbeds is point loading or concentrated loads, and what we call imbalanced loading,” Giles says. “If you’re going to have a concentrated load, we recommend having it toward the middle.” An example is a steel coil. “We usually put a sticker somewhere in the middle, saying ‘Load here’ or ‘Load a single coil between the kingpin and the center of the rear axles,’” he says.

By “imbalanced,” Giles means weight “on the wings or any portion of the deck that is outside the main beams.” For example, if you frequently transport wide-track vehicles with little or none of the weight over the main beams, you can bend or deform the trailer, Giles says. If you consistently run with more weight on one axle, its tires can sustain abnormal wear.

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