Feature article: Watch your weight

Max Kvidera | January 01, 2010

Some states have grandfathered in higher weights. Some of the higher weights are permitted if spread over a specified number of axles. Several states allow longer combination vehicles. Many states permit higher weights on state roads.

W= 500      [ LN/N-1]

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Another exception is that two consecutive sets of tandem axles may transport 34,000 pounds each if the overall distance between the first and last axles of these tandems is at least 36 feet.

For more information, go to ops.fhwa.dot.gov/freight, click on “Publications,” then “Vehicle Size and Weight.”


Onboard scales help figure weights

Using an onboard scale can help you maximize your payload. The degree of accuracy varies, depending on the system used, but even a rough estimate can be helpful until you reach an official scale.

An onboard scale can be an aid in positioning air ride suspension. Some scales sense air pressure and give pressure readings, while others give a digital weight readout.

Owner-operator Fred Jones says he uses air gauges for both his tractor and trailer. “I set my gauges to weigh about 500 pounds heavy,” he says. “As long as I get up to that point, I know I’m going to be OK on weight. Over that weight, I know I should find a scale soon.”


More weight: A distribution challenge

The debate over increasing the maximum tractor-trailer weight limit on federal highways to 97,000 pounds raises an issue not just for total weight, but also axle weight.

House Bill 1799 would raise the total weight to 97,000 pounds. An opposing measure, House Bill 1618, would maintain the current limit of 80,000 pounds on all federal highways.

Any increased weight wouldn’t be all payload. Instead, you have to account for the added weight of a third trailer axle, notes Great Dane Trailers’ Adam Hill.