Truck Topics
Test Drive - The New Acterra!
The Acterra 7500 Tractor This attractive little unit was equipped with the Mercedes-Benz MBE 900 six-cylinder that is the standard power in Acterra. For the Class 7 application intended for this model, the engine is rated 280 hp at 2,300 rpm with 800 lbs.-ft. of torque at a low 1,250 rpm. It was packaged with an Eaton FSO-8406A, six-speed synchromesh transmission and a Meritor RS-21-145 drive axle.
This 106-inch BBC axle-back Acterra 7500 is rated for 35,000 pounds GCW, which puts it right at the top end -- or a little over -- for Class 7. Still, the compact dimensions, a 50° wheel cut and the curved front corners make the truck highly maneuverable. We measured turning circles, which were an impressively tight 45 feet curb to curb.
Equally impressive is the view out. We also checked the closest distance the driver can see to the road and measured it at a short 12 feet. The view out the sides is also good, aided by the deep side glass that dips toward the front. A small peeper window in the passenger door helps with the curbside view, too.
Windshield "A" pillars aren't intrusive, though the big West Coast mirrors get in the way somewhat, especially on the driver's side. A major plus with the mirrors on this truck, though, was the motorized adjustment from a neat, car-type switch mounted in the driver's door.
The car-type feel extends to the dash and soft trim around the cab. It is a no-nonsense setup with easy-clean vinyl throughout and rubber floor mats, but there are coat hooks and a storage unit between the seats. A corporate EzyRider air-suspension seat eased the ride in this air-braked tractor.
But, as we soon found, the ride on the new Acterra is very acceptable. We had picked up an empty 28-foot pup van and found the Freightliner-derived AirLeaf rear suspension and the unique new leaf-and-a-half front springs provided a really excellent ride. This is noteworthy, since the cab was mounted on elastomer bushings rather than the optional air suspension.
Steering was precise with no lost motion. The steering column was adjustable for a good driving position, too, aided by the long seat slides that are a feature of the Sterling cab.
The clutch was light and progressive and the brakes had excellent modulation, which makes stop-start operations much gentler on the driver. The Eaton shift quality was also smooth, with the synchromesh easing the shifts without any trace of balking. Throttle response of the MBE also made for smooth progression through the gears.
The performance from the Mercedes-Benz engine was also well-matched to the distribution task, allowing for second-gear starts. It pulls well from low rpm, allowing for early shifts and quick gear progression to run with traffic. The engine's peak torque allows for urban freeways to be negotiated in 6th gear. The rear axle ratio geared the Acterra to run 2,350 rpm at 60 mph. All-out, the truck would run close to 70 mph at the governor.
The Cummins ISB that powered the straight truck is generally noisier than the Mercedes engine, so the Acterra should be nicely quiet. The sound-level meter registered a maximum 72 db(A) at 55 mph and a very quiet 60 db(A) at idle.
The 250-hp ISB in the 23,500-pound-rated 6500 chassis was coupled with an Allison MD3060 to make it a very lively delivery vehicle with about a 65-mph top speed. Again running empty, we found it raced up to speed on freeway onramps. Additionally, the automated shift made it an incredibly easy vehicle that any license holder could drive.
The 6500 shares the 7500's good visibility, though sitting a couple of inches lower makes forward visibility even better.
This truck was equipped with 19.5-inch wheels. The suspension was steel springs all around with a conventional taper leaf up front. The ride, with the longer wheelbase, was again good. But it was the ability to steer the little truck around the tight streets that impressed most.