Ease on Down the Road
A rig review of the new Kenworth T700 with a PACCAR MX engine
By Paul Abelson
Automobile manufacturers bring out new models on a regular basis and totally redesign cars and pickups every three to five years. Heavy truck builders rarely change models. It’s been more than a decade since Kenworth introduced the T2000, its first wide-bodied aerodynamic truck for the 21st century.
Kenworth had earned its reputation among owner-operators with traditional narrow cab conventional tractors and, back in the days of length laws, with full width cabover-engine (cabover) trucks. Today, cabovers abound in Europe where road conditions favor them, but they are gone from American over-the-road truck builders’ lineups. The curved, aerodynamic surfaces of the T2000 improved fuel economy up to one mpg when comparing similarly spec’d conventional trucks and more when matched against cabovers, but traditionalists were unhappy with the shape.
In the decade that followed, truck architecture has been increasingly driven by emissions controls and fuel efficiency. Extra cooling capacity was needed for exhaust gas recirculation (EGR). Designs had to make room for diesel particulate filters (DPFs) and selective catalytic reduction (SCR) devices and extra tanks for specially formulated urea, the diesel exhaust fluid (DEF) required for SCR.
That decade also saw Kenworth and its sister company Peterbilt (both owned by PACCAR) continue to keep their strong positions in the premium owner-operator market, albeit with improvements to their traditional long-nose trucks. The T600 was refined into the T660, a somewhat more aerodynamic version. Peterbilt smoothed the edges of its 379 and came up with an aerodynamically improved version, the 389.
This year at the Mid-America Trucking Show, both PACCAR companies introduced redesigned and re-engineered trucks and tractors. They also introduced their proprietary PACCAR engines, expanding the trend to vertical integration among truck builders.
When Kenworth invited me to the PACCAR Technical Center near Mt. Vernon, Wash., to drive some new trucks with new engines, I jumped at the chance. Naturally, I selected a couple of T700s to test. With its full-width cab, this is the flagship of the fleet, a replacement for the T2000 with the looks of the more traditional T660.
Those looks are more than just aesthetic. The T700’s lines are highly functional. Good aerodynamics are achieved by keeping the air flow from changing direction to the greatest extent possible. The T700 and its sibling, the Peterbilt 587, have smooth sides running from the grille opening to the full width of the sleeper cab in one continuous curve. There are no dips or reverse curves along the way, making the trucks among the most aerodynamically efficient ever designed. The less energy is needed to force air to change direction, the less fuel is needed to create that energy; therefore, the truck gets better mpg.
Both T700s I drove were loaded close to 78,000 lbs. Both had 75-inch Aerodyne sleepers. One was powered by a dual-rated Cummins ISX with 425 hp and 1,550/1,750 lb-ft of torque at 1,200 rpm. The other had PACCAR’s new 485 hp (at 1,900 rpm) MX engine with 1,650 lb-ft at only 1,100 rpm.
The Aerodyne sleeper is evolutionary, with new levels of refinement introduced based on driver feedback. In the T700, the “cathedral ceiling” allows any trucker to easily stand tall. Of course, I don’t know any 8-foot tall truckers. There is a Diamond VIT trim level, but the standard Splendor trim, even without the VIT’s diamond tufting, wood grain inserts and embossed emblems, looked luxurious to me.
An optional adjustable TV mount is said to handle a 16-inch flat panel screen, but I wouldn’t be surprised if a 20-inch HDTV would fit. Another delightful option is the refrigerator with slide-out drawers, laid out for easy access to multiple levels of chilled goodies. They’re easy to get to and to put away.
While chrome is king in some circles, in others “less is more.” I like the way the two-piece bumper (for easier repair and replacement), painted to match the body color and aerodynamic fairings, sets off the bright Kenworth grille shell, with its bright aluminum wire inserts.
The T700s had PACCAR’s smart steering wheel with cruise control switches under my left thumb and engine brake controls under my right. The sloped aerodynamic hood had smooth, direct, gentle curves from the oversized grille to the back of the cab. Aerodynamics work best when the air flow changes direction as little as possible. With its straight air flow, the T700 is one of the most aerodynamic and thus fuel efficient trucks on the road. The hood slope also contributed to air flow and to excellent visibility, as did the large windows and aerodynamic mirrors. I had no trouble seeing traffic all around me.
On the road
The route we chose had a combination of sharp turns, both rough and smooth blacktop and concrete roads, railroad tracks, Interstate highways and, south of Mt. Vernon on I-5, Conway Hill — a 4 percent grade that ran nearly a mile. Both trucks had Eaton Fuller UltraShift Plus transmissions with Hill Start Assist. The trucks handled the grade easily, starting each climb at 62 mph at only 1,240 rpm in cruise control at the bottom. The PACCAR-powered truck held 55 mph at 1,100 rpm up to the top. The Cummins engined T700 started climbing at the same speed and topped out at 57 mph due to more torque and more gears. You’ll have to decide if the higher priced transmission is worth it.
An outstanding feature of either UltraShift Plus transmission is its ability to hold on a grade while the driver’s foot goes from brake to accelerator. There is no roll back or forward creep.
The ride inside the spacious cab was almost like an SUV, with little jarring or shaking, even when crossing railroad tracks. Turns were tight and precise, with excellent road feeling through the steering wheel. There was a strong feeling that the truck would go wherever I wanted.
Next year, new stopping regulations will come into effect. In anticipation, I also drove a “baby 8” three axle straight truck, the T370, fitted with a tank body. The tank was empty, so performance impressions would be meaningless, but the 350 hp PACCAR PX-8 in-line 6 engine seemed more than adequate. The truck had the smallest Kenworth DEF tank (9 gal) but like all SCR-equipped trucks, the tank is adequate for at least two fill-ups of the main tank. Larger tanks are optional.
This particular T370 had a 16,000 lb front axle and air disc brakes all around. Ride was a bit harsher than the T700, with some bouncing off the more severe bumps, but directional stability was outstanding. During heavy braking, lateral stability was excellent. The disc brakes eliminated any hint of side pull, with straight, precise stops time after time no matter how hard I braked. The only reason I tried hard braking with a tank was because it was empty (no slosh).
In fairness, what can be said of Kenworth T700 also applies to its counterpart, the Peterbilt 587. They were developed in parallel at the PACCAR Technical Center.
But each brand does have its subtle differences and its own loyal following. When you’re next in the market for trucks, don’t just think of your traditional sources. These 2010s from Kenworth and Peterbilt are certainly worth a look and a test drive.