Booster Axle Puts 24.5 Tons In the Box

September 28, 2010

Six axles that span 35½ feet with the booster deliver a straight truck that's Interstate legal at 75,500-pounds GVW.

Jeff Sutton's Sutton Trucking needed a truck suited to four different sets of weight rules: federal Interstate limits, state restrictions in Missouri and Kansas, and municipal laws for the commercial zone in a 50-mile radius around Kansas City.

Maximum weight allowed in the commercial zone is 22,400 pounds on any single axle and 36,000 pounds on a tandem. On Interstates, trucks are restricted to 20,000 pounds on any single axle and 34,000 pounds on a tandem. Allowable gross depends on the distance from the first to last axle.

Their solution is a Kenworth W900S Super 16 dump truck with six axles: a set-forward steer, two steerable pushers, tandem drives, and a booster axle that swings down from the rear on hydraulic arms. The outer bridge is 35 feet 6 inches, which can carry 75,500 pounds GVW.

The booster axle bears up to 13,000 pounds and cantilevers weight onto the steer axle.

"The Super 16 lets us scale almost 24½ tons of payload," Sutton says. "It basically does the same job as a tractor hauling a 40-foot frameless end-dump trailer, which scales at a little more than 25 tons of payload. Yet it's more maneuverable and costs less to insure.

"When you show up on a job hauling six or seven more tons than the trucks other guys are using," Sutton adds, "that's what makes customers happy and keeps them calling back."