July 2007, TruckingInfo.com - Test Drives
The return to the International ProStar saw us approaching the truck with high hopes. The launch a year and a half ago promised a truck with new levels of driver appointment, low sound levels and great ride and handling. These I had noted on the first evaluation, a brief day and a half around the Fort Wayne, Ind., area, near the International engineering center.
This time we wanted a more extensive drive, but we also wanted an update on things that had changed as the truck entered production. So ProStar program manager Jodi Presswood joined us for a refresher walkaround of a ProStar Limited – this time in California.
Day One of a three-day test saw us at the TravelCenters of America travel plaza in Ontario, right at the intersection of I-10 and I-15. Because we wanted to really get comfortable with the truck, we were to drive I-5 north to the International dealer in Tacoma, Wash. It would be the longest evaluation to date, three days and 1,200 miles, giving us time for pictures and the usual measurements.
Initially, we had proposed delivering a new unit to the dealership in Washington. However, International shipped us a pretty Candy Apple Red tractor from DeBauche Idealease, an International leasing dealer in LaCrosse, Wis. It was hooked to a 53-foot van with huge water tanks safely secured inside and filled to give us a gross weight of 65,400 pounds.
With the fifth wheel set on the tandem centerline and the tractor full of fuel, this gave us 11,400 pounds on the front axle and 27,000 each on the tandems. We didn't weigh the tractor, but the manufacturer weight tag said it was 18,580 pounds with about 60 gallons of fuel and a driver aboard.
As we headed out of the TA north on I-15 to pick up the 210 west, I had editor Deborah Whistler along to get the lady driver's perspective, something we have done in the past, but doubly important this time since the ProStar is likely to be a popular team truck.
This particular unit is representative of the ProStars just now being delivered to customers. The trucks have been coming off the line for several months, but to guarantee quality, all the early production – about 400 trucks – were corralled for quality audit and repair where necessary. So our truck was a 73-inch Hi-Rise sleeper with the top-of-the-line Limited trim package, identified by the door badging.
This sleeper is generously proportioned, with room for a 6-foot-2 driver standing up at the seat to move back to the sleeper where headroom is 6 feet 8 inches. It requires a roof fairing to lift the roofline up to trailer height for optimum aerodynamics. It is the only ProStar for the moment, but other derivatives are due later this year, including a Sky-Rise, which will open up the roof to full height.
The current 73-inch sleeper can be spec'd with a single bunk, like this example, or with upper and lower. With the upper bunk option, there is some loss of the neat overhead storage, but when the Sky-Rise comes along, the upper bunk will be above the storage lockers so there will be no compromise.
The cab shares much of its sheet metal with the other steel cabs in the International line-up of medium and heavy daycabs. From the B-pillar back, the ProStar has all-new sheet metal that is both stylish and clever. The side panels flare out to maximize sleeper width and include a generous side window and baggage access doors. There's also a styling line that continues the visual sweep from the cab doors and windows. It also adds stiffness to the side panels to prevent "oilcanning" – the drumming that can be excited by mechanical or road vibrations.
Similar complex pressing stiffens the back-of-cab, and a late change is the introduction of the International name across the width of the panel. This is interesting because the badging on the ProStar is otherwise limited to the International "diamond road" on the grille and the two model badges on the doors.
Obviously roof and floor are unique to the ProStar. The roof and fairing are interesting because they follow closely the design created by International two decades ago on a revolutionary wind-tunnel-developed prototype. Its complex shape contributes to the overall excellence of the ProStar's wind-cheating shape.
The floor is interesting, too. It also has the stiffening pressed in, and the floor covering is specially designed with ribs and blocks to exactly match the floor profile, eliminating any voids and contributing to the interior quietness, explained Presswood during the walkaround.
The cab is suspended, of course, but the ProStar has two strut-type dampers with air springs. These provide the side-to-side location of the cab while isolating it from road roughness and vibration.
Another trick feature, this time up front, is the unique bumper assembly. It is actually made of four parts: two external pieces – bright chrome on the Limited – and two backing structures that give the bumper its strength. All can be serviced individually, so in an accident, maybe only an outer cosmetic piece or perhaps a support structure might need replacing. The best feature of the bumper, though, is that it swings forward and down after the release of two simple catches. This makes it very easy to step in ahead of the steer tires to get at the check and fill points. Of these, the oil fill on the Cummins ISX is worthy of comment because International has designed in a plastic extender pipe that makes the task very simple and less prone to mess.
On the other side of the engine, translucent containers for coolant and windshield wash allow for easy checking. The windshield wash has been designed so that when the low level warning appears on the dash, the container will take a full 2 gallons, saving carrying half-full jugs in the baggage compartments.
Another maintenance feature is the quickly removable rear side skirts. A lever on the back side rotates a bar that retains the lower mounting points. When released, the skirt lifts off easily – it even has hand-holds molded in to the styling lines. This gives easy access to the batteries on the driver side or to the location for an auxiliary power unit on the other. An APU will be a factory-fitted option later this year.
Under the easy-tilt hood – a small woman could tilt it – our test unit featured a 485 Cummins ISX with the full 2007 EGR and aftertreatment package. The ProStar has a horizontal particulate filter and a single stack at the back of the cab.
The 485 is rated 1,650 pounds-feet at 1,200 rpm (there is a higher 1,850 and a Smart Torque dual rating as well) and drove through the familiar Eaton Fuller 13-speed. Gearing was 3.45 to one, which gave a very satisfactory 62 mph at 1,300 rpm in overdrive top gear. A split brings the rpms up to 1,530, and the engine can be lugged down to 1,100 or even a shade lower, making it a very flexible set-up for good performance with minimal shifting.
The wheel and tire equipment featured forged aluminum wheels with International's hand holes, General 22.5-inch tires on the steers and Bridgestones on the drives. Brakes were drums all round and the steering was by TRW.