Granite Packs More Punch and Comfort

Sept. 28, 2010

Pity the guy who drives a Mack? Not at all. His old-style DM or RB truck or RD tractor may be short on room and ride a little rough, but they've got a compact feel and good visibility that makes them easy to maneuver. Moreover, these beasts are so tough that their owners are almost certainly making money, and that means job security.

And look—here comes another Granite. Last year we saw the trucks that will eventually replace the older vocational models, and now there's a tractor version for your lowboy, equipment hauler or end-dump trailer. Whether or not you now run Macks, this new model will open your eyes and please all your senses.

It's a handsome rig, with styling that should look fresh for many years, just as previous Mack models have. Climb into the cab and look around. It's big. Crank over the engine, put 'er in gear and drive away. It's smooth and quiet. Room and comfort are the Granite's most obvious attributes, but Mack says it's also got modern electronics and the strength you'd expect from a Bulldog.

Like the Granite and Granite Bridge Formula trucks we drove last year, this Granite tractor has an extra strong frame and a specially reinforced cab from the CH/CL models. The cab has big windows and doors, a lot of interior space, excellent instruments and good controls, and pleasant interior appointments.

Interior amenities

The premium-level interior trim matches the look of many luxury cars, yet retains a big-truck feel. There are pockets in the doors and nooks in the overhead console for storage. Cup/bottle holders are just below the dash, and between the seats is a roomy chest with a power point to support a laptop PC or small cooler. The AM-FM-cassette radio is handily placed in the dash; heater and air conditioning controls are just below, and have familiar twist knobs.

Big rocker switches are easy to punch, once you figure out the "international" pictograph labels. Mack's gauges, particularly the speedometer and tachometer, are large and legible—the best in the business, in my opinion. This tractor had the Vehicle Information Profiler (VIP) electronic display that's linked to the Vehicle Management and Control (V-MAC) electronics that run the engine and other systems. You can get all sorts of operating info and diagnostics help by scrolling through the luminescent display.

There is one throwback: a roof air vent. "The RD has a roof air vent, so we put one in the Granite because we figured operators will ask for it," explained Steve Ginter, director of vocational sales who showed me around the tractor and trucks last year. The pop-up vent increases airflow through the cab, but just remember to button it down when you run the air conditioning.

Driving this Granite was a lot like wheeling a Vision highway tractor. With windows up, outside noise was muted. The Granite's huge windshield revealed a wide view of the world, and the steeply sloped hood let me look closely at the pavement just ahead. Cutdown side windows in both doors, plus a peep window in the right door, show what's happening alongside.

This tractor had a pre-October 460-hp E-Tech diesel, which is a wonderful engine to drive—lots of power and torque, and with Mack's latest 18-speed, there is never a situation where there's no transmission ratio to handle it. We towed a special Rogers trailer that resembles a container chassis with big, heavy concrete blocks; these ballasted the rig's gross combination weight to just about 80,000 pounds, Ginter said.

Driving with the greatest of ease

The trailer is not licensed for the road, so we stayed on the test track that surrounds the tech center in Allentown. There was enough room for me to get up to about 55 mph for short bursts, and plenty of opportunity to go up and down through the gears. The T318L 18-speed has a low-inertia shaft design that allows clutchless float-shifting, with little or no practice. Mack's public relations counsel, Mike O'Neill, got in and drove it away, even though he's driven only one big rig before, and it had an Eaton AutoShift. He was like a kid with a new Tonka truck.

As with a Fuller 18-speed, the Mack transmission consists of a 9-speed main box with a 2-speed splitter. You can split every main ratio or none of them, depending on conditions and your preferences. I tended to split most gears just for the fun of it, but on the level it often makes more sense to avoid the splitter. Accelerating downhill, you can upshift at low revs, using only the main gears and letting gravity do the work.

Climbing uphill, the splitter allows you to quickly step your way through the ratios. Less rpm drop between each ratio lets you accelerate when you'd otherwise have to stay in a gear right up to redline, for fear of losing revs and momentum as you try to grab the next higher gear.

No matter what you do with the transmission, the E7-460 has the grunt that both accomplishes a heavy-hauling job and enriches the driving experience. As a bonus, the engine makes a throaty exhaust note. Come Oct. 1, Granites will get Econodyne or Maxidyne diesels with internal exhaust-gas recirculation. The lighter Cummins ISL is also available.

A smooth ride

The Granite tractor's ride is smooth and shock-free, thanks to considerable development work on the chassis and the air bag/shock absorber suspension at the cab's rear. This, too, sets the Granite apart from the R-based tractors and trucks, and as customers learn of it, ought to hasten the old models' demise.

Some customers might buy a Granite to pull bulk trailers, but they'd be buying more than they'd need for the highway. And the internal EGR would use more fuel than MaxiCruise diesels that will go in CHs and other highway vehicles. They will use Mack's more complex cooled EGR system, but at cruising speeds will be as much as 5 percent more fuel-efficient than the I-EGR'd diesels. But I-EGR is simpler and, Ginter said, about as efficient as current engines in stop-and-go service seen by construction trucks.

The Granite shows every indication of being as rock-solid as its R-based models, but delivers its driver from the cramped confines and sometimes rough ride that heretofore came with signing onto a dumper or mixer fleet dominated by Macks. If you see guys or gals in Granites, you can now envy them.

2002 Granite
The handsome Granite has a steeply sloped nose for good visibility on or off road.
The handsome Granite has a steeply sloped nose for good visibility on or off road. Here it's coupled to a test trailer, but it's built to pull lowboys, end-dumps and the like.
Well-thought-out steps and handles make climbing into the cab or onto the rear deck safe and easy. Doors are big, and the interior is roomy.
Premium interior features simulated cherrywood dash with large, legible gauges and big rocker switches. Roof has an air vent familiar to drivers of the old RD, RB and DM models.
Mack's 12-liter E7 will come with simple "internal" EGR in October. Lighter Cummins ISL is also available in the Granite, and ISX can be had in the long-nose CL.
Test Set

Tractor: 2002 Mack Granite, conventional daycab on rear air-ride, 108-inch BBC

Engine: Mack E7 E-Tech, 12 liters (733 cubic inches), 460 hp @ 1,850 rpm, 1,660 lbs.-ft. @1,200 rpm

Transmission: Mack T318L 18-speed double-overdrive

Front axle: 14,300-lb. Mack FAW14.3 on taperleafs

Rear axles: 44,000-lb. Mack S440 w/4.35 ratio, on Mack four-bag air-ride

Wheelbase: 210 inches

Brakes: Meritor S-cam w/Meritor Wabco ABS

Tires & Wheels: Goodyear 11R24.5 G159A front, G244 rear, on Alcoa aluminum discs

Fuel Capacity: Twin 95-gal. aluminum tanks

Trailer: 48-ft. Rogers chassis w/concrete ballast

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