Sterling Truck Corporation has introduced a new chassis for its A- and L-line trucks and tractors.
Designated the HX chassis, the new design replaces the HN80 chassis from earlier Sterling models.
The HX chassis is the result of a need to upgrade cooling capacity in all Sterling trucks to accommodate the new engines, Landon Grogan, program manager for the HX project, said. In addition to changing the cooling system, the HX has a new design for the front of the frame, new front suspension, and enhanced steering. While making these changes, Sterling has produced strong, lightweight frames, a new proprietary cab air suspension, and new fuel tank options.
The new cooling system uses an aluminum radiator. It is available in 1,000-, 1,200-, or 1,400-sq inch sizes. The 1,200- and 1,400-sq inch radiators have the capacity to handle the cooling requirements of engines up to 500 horsepower.
Cab positioning has been adjusted to provide room for the larger radiators. The new design braces the radiator to the cab and uses narrow-based radiator isolators for increased strength. Radiator mounting is the same for all three BBC lengths — 101, 111, and 113 inches — in the Sterling line.
Product continuity
The cab is the same as previous Sterling trucks. The design is only five years old and is well accepted by the company's customer base, officials said. Instead of introducing a new cab appearance to go with the new chassis, Sterling chose to maintain product continuity for customers.
Sterling made extensive changes to the frame of the new HX chassis. In addition to the 10- and 11-inch frame sections from previous Sterling chassis, the HX also offers a new 13-inch frame section. The frame is built with five-piece welded cross members. All frame reinforcements are now a 1/4-inch C-channel installed inside the frame to provide a consistent frame rail height and frame width. Sterling's previous practice of reinforcing the frame with an exterior channel, an outsert, caused some difficulty for body builders. With inserts, the new HX frame can provide a resistance bending moment of up to 5 million inch-pounds.
The new frames are produced with Sterling's “Optilock Chassis Grid System” that standardizes the layout used for punching holes in the frame. The grid system provides five rows of potential hole locations, each spaced roughly two inches apart. All frame components mount within this grid pattern. In addition, Sterling can pre-punch the frame for bodies and equipment to be mounted later.
Fuel tank options have been simplified for the new HX chassis. The Sterling standard now is a 23-inch diameter cylindrical aluminum tank with an option for a 25-inch diameter. Tank capacity ranges from 50 to 150 gallons. Tanks are mounted with cast aluminum brackets for lighter weight. On most trucks, fuel tanks are mounted to the frame under the cab so that the frame is clear from the back of the cab all the way to the rear.