STERLING Trucks has expanded the Acterra line of medium-duty vehicles with a four-door Crew Cab option for vocational applications. The new product includes the industry's largest interior passenger compartment, measuring 113 inches from the front to the rear wall inside the cab, said Jim Crowcroft, manager of product marketing, during the 39th annual NTEA Convention and Work Truck Show in Atlanta, Georgia.
“The 163-inch BBC Crew Cab is 15 inches longer on the inside than any other factory crew cab on the market today,” Crowcroft said. “It offers significantly increased overall headroom and legroom due to a flat floor front to back and a tall concave steel roof. The cab also uses a monocoque all-welded steel cab construction reinforced with corrosion-resistant galvanized steel panels. With gross vehicle weight ratings from 19,000 to 46,000 pounds, the Crew Cab is well suited for construction, utility work, municipal service, or firefighting applications.”
Full-length exterior cab steps and grab handles are placed on the outside of the cab and inside each door to further aid entry. Standard fixed or optional air-ride seating for front passengers, plus a standard full-length three-person bench seat in the rear, make comfortable accommodations for five persons. An air-ride cab suspension is standard with the new Acterra Crew Cab to allow for improved ride quality.
The Acterra Crew Cab features multiple diesel engine options, including the standard MBE900, rated from 170 to 300 hp, and the optional Caterpillar 3126 and Cummins ISL and ISC, with ratings from 190 to 350 hp. Transmissions include those from DaimlerChrysler Powersystems, Eaton-Fuller, and Allison.
Sterling also announced a factory-authorized All-Wheel Drive Conversion for Acterra trucks. Manufactured by Fabco Automotive Corporation, the All-Wheel Drive feature is available for all Acterra 4×2 versions. Conversions for Acterra 6×4 trucks are expected later this year.
The AWD Conversion is offered with front axle ratings of 12,000, 14,000, or 16,000 lb and comes with a choice of one- or two-speed transfer cases. The conversion is available for Acterra products equipped with MBE and Caterpillar medium-duty engines and with transmission choices from DaimlerChrysler Powersystems, Eaton, and Allison.
The conversion features an offset front drive carrier axle and four-shaft transfer case designed to ensure a minimal increase in vehicle height of only four to six inches over standard height. The offset carrier and transfer case output shaft allow clearance around the oil pan. This reduces the amount of space the chassis must be raised. Coupled with no step frame modifications, the AWD retains frame integrity and durability, maintains a low center of gravity, and eliminates up to 300 lb, which allows for increased payload capacity. Driveline angles comply with industry standards, and a single piece forward driveshaft avoids the cost and weight of a two-piece shaft. For operator convenience, the AWD system is engaged through two electro-pneumatic switches on the dash.
“Last September, Sterling revised the Acterra with hundreds of new features and improvements,” Crowcroft said. “One of the most important changes is the completely revised chassis design, including new frames and crossmembers.”
Acterra frames use stamped dog-bone crossmembers that reduce the chance of stress-related failures. Fasteners have been standardized to 5/8-inch dimensions. Grade-8 bolts ensure durability and maximum chassis strength. Hub fasteners can be specified in areas of the chassis where access to bolts is difficult for regular maintenance. A computer controlled pattern of 50-mm frame drillings along the chassis from behind the front axle to the front of the first spring hanger allows for better placement of inner and outer frame components.
The new front suspension for Acterra incorporates a single-leaf spring as standard equipment. Taper-leaf suspensions are available ranging from 8,000 to 18,000 lb with maintenance-free rubber bushings. Flat-leaf springs are rated at 14,600-, 16,000-, and 18,000-lb capacities.
“The new spring design provides a better ride because there's less spring friction to overcome, plus they are lighter in weight and provide a more comfortable ride when the truck is empty,” Crowcroft said. “These new springs also feature polymer maintenance-free front-spring bushings. For 4×2 applications, a replaceable spring deflection pad is used instead of a shackle on the rear of each front spring. The 12,000-lb front suspension option is supplied with a single-leaf spring and a rear spring shackle, plus rubber spring bushings on both ends for longer life and improved ride. The rear suspension has a lube-free design.”
The standard 52" variable rated taper-leaf spring is equipped with slipper pads. The polymer slipper pad reduces wear to the rear shackle and reduces spring banging. Options include shock absorbers, a rubber helper, and stabilizer bar. A six-step range of capacities from 10,000 to 23,000 lb is available. The optional 60" two-stage spring rear suspension package comes in 18,000, 21,000, and 23,000 lb ratings. It includes shock absorbers, shackle rear mounts, rubber helper, and anti-friction spacers. An optional stabilizer bar for single axle spring and air suspensions provide additional roll stability during turns, which is especially important for high-center-of-gravity applications.