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.
The interior of the cab is undeniably handsome, with light and dark grays for the trim and nice wood accents that come with the Limited package. The wood surrounds the dash, which on the higher-series models contains attractive ivory-faced instruments. These are evenly illuminated at night, when the faces seem to darken to a charcoal to contrast with the excellent illumination for the numbers and the gauge pointers.
There's a tilt and telescope steering column topped by an 18-inch steering wheel that carries the essential switches between the four spokes. Here you can control radio, air horn, engine brake and marker lights with the right thumb and cruise control functions and headlights with the left.
An array of warning lights in the panel top and center is complemented by a driver information panel lower in the dash. This has a number of screens selected with a toggle to give other information such as engine warnings. Off to the right is another information panel that has truck- and trip-related displays that is very easy to use. It is ported for a number of additional functions, such as an upcoming navigation system, that were not enabled on this unit. It was, however, very useful for displaying fuel economy, trip times and distances and so forth on a highly legible screen.
Another good feature is the rotary controls for the HVAC system. However, we fumbled with them trying to get the right amount of air. It would be nicer to have a climate set point where you dial in the temperature and the system takes care of you. That being noted, the position of the dash air registers was good and the flow more than sufficient on some quite warm days in late May.
At the base of the wing dash are cupholders – or more correctly giant gulp holders. In the driver's holder, a regular-sized cup of coffee just disappears. A removable ashtray makes for an added holder, too. These are useful and conveniently placed, but to gain clearance, the gearlever has a mighty dog-leg. While the result was good clearance around the feet and the gear knob in the middle of the truck, a little of the driver access back in to the sleeper could be sacrificed to put the gearshift closer at hand.
Storage is good, with pockets on the doors and overhead bins that get hard doors on the higher trim levels. Above these and continuing throughout the cab and sleeper is a high shelf. A center stack over the windshield has a couple of pockets and was originally intended for a CD player stack. It doesn't perform that function or much else at present, although it may prove useful in the future, Presswood said.
The seats are mounted to long slides, allowing for some very big as well as small drivers. I set the seat – an International model by National – several stops from the end of the slides.
The seats are comfortable and feature a wide range of air-controlled configurations such as lumbar and shoulder support. Driving was mostly in two-hour sessions with plenty of breaks, but we experienced no real sense of tiring in the three 10- to 12-hour days.
Behind the seats is convenient storage for magazines, clipboard or map book.
The seats sit fairly far apart so that even with armrests there's a 21-inch pass through. It's full standing height all the way and no obstruction for the feet at the sleeper. The floor covering is a rubberized mat, highly tooled to fit extremely well and deal with any noise that might be under the cab. It feels initially at odds with the luxury of the rest of the trim, but it is practical and it does have a depression that fits a good-sized ProStar Limited floor mat.
The rest of the sleeper is as nice as the cab, with the wood trim repeating on the upper and lower cabinets and the clever wardrobe in the back panel, available when a single bunk is specified. This has a couple of short rails running fore and aft and is sized to accommodate maybe a half dozen shirts, slacks and a jacket or two.
The upper storage at the sides is neat. It is described as airliner storage and functions much like the overhead bins in planes, with doors that rotate down. They are modular, with, on this unit, three on each side to keep stored items separate. Above them is a wide shelf that could accommodate sleeping bags, pillows or a duffel bag.
A hanging wardrobe is on the driver's side with a TV shelf, pull-out work surface and a three-drawer stack facing on the other side. The sleeper is configured to accommodate a microwave on top of the wardrobe and a refrigerator under the worktop.
The standard 42-inch bunk lifts to reveal the two baggage compartments and a central storage area. Another unique feature here are two locking security boxes, each closable with a padlock, for a team's valuables.
The interior is bright, with two large opening windows allowing for ventilation. Some drivers don't care for sleeper windows, but I find them a big safety plus when pulling up at an angled intersection or backing on the blind side.
ON THE ROAD
The first day was pretty much freeway all the way after a relatively late start. Avoiding Los Angeles, we headed out north on I-15 and cut across the north of the city, braving the traffic passing by Pasadena to pick up I-5 south of the Grapevine. Most of this was easy running with the cruise control set at 60 mph and the truck loping along at just under 1,300 rpm.
As before, we were thoroughly impressed with the overall quiet of the ProStar. It wasn't until later that I put the sound meter on it, but when I did, the readings of 66 dB(A) on cruise and 68 dB(A) under full load (45 mph, 75 percent engine rated speed and full throttle) were recorded. Even more impressive was the quietness of the engine brake, or Intebrake. This is the retarder built in to the ISX with three performance levels. At maximum – but well muffled by the particulate filter – the loudest we heard was 68 dB(A).
This is a great tribute to the integrity of the cab and floor sealing. Also, we noted none of the aggravating booming periods some cabs make. At this writing, the ProStar leads in offering a quiet interior. But the new Freightliner Cascadia is claimed to be mighty quiet, too.
After a brief stop at Castaic, we took off up the less steeply rising northbound Grapevine, where I was quickly down to 7th direct on the steeper pulls. At one stage, after a particularly balky, steep section, I dropped to 6th direct, but was able to pull up a half gear before getting to the top. Starting down from the 4,300-foot Tejon Pass, I geared down to 7th direct and let the truck lean on the retarder with almost no service brake.
Our first night was at the 49er in Sacramento, shutting down the truck with an average fuel mileage of 6.0 mpg. This was from a zero at Castaic, just before pulling the long grade, because I failed to get the trip to zero and latch on leaving Ontario. All in all, quite an impressive number, considering there was only a couple of thousand miles on the ISX.
I noted that the trailer gap was a lot larger than we would have liked. Earlier in the day we slid the trailer up a little – perhaps too much, given how heavy this particular tractor was on the front end.
On Day Two, we drove I-5 to Exit 747 and turned off at Weed, Calif., for U.S. 97 toward Klamath Falls. Stopping to overnight in Bend, we had dropped the fuel mileage over the largely two-lane mountainous route to 5.7 mpg. Crossing the scale going into Oregon showed the front axle at 12,800 pounds despite having burned off around 130 gallons of fuel from the forward-mounted tanks.
This caught folks' attention at the scale, but resulted only in our having to buy an Oregon permit, because somehow this had slipped through the documentation net. Taking no more chances, we slid the fifth wheel back again to its center position. To heck with fuel mileage.
Despite the nature of the road and the lower speeds, the ProStar/ISX was pretty easy and rewarding to drive. The ISX pulled strongly, with the good throttle response we have noted since the advent of variable geometry turbochargers. The lower speeds got us into more gearshifting but it was relatively easy stuff.
On Day Three, we ran north to The Dalles, then west on I-84, soft-pedaling or using cruise control and picking up the odd 1/10 mpg so that by the time we cruised in to the Tacoma dealer we were right on 5.9 mpg.
Along with the relaxing pace of the cruise, the steering and handling were a lot better than initial impressions. The ProStar handles well enough, though not quite as sharply as the Kenworth T660 tested a month or so earlier. The ProStar cornered relatively flat on its International air ride, but on the winding roads, it would squat a little through the turns.
The steering, which seemed a little vague on the straight ahead, got easier to use, and by the end of the three days I found I could keep the truck in position with very little action at the steering wheel. The International engineers had told me previously that the TRW gear has been sharpened up for the ProStar, and by the end, I found myself in agreement.
Braking was nicely progressive with good feel and power in low-speed stops.
International says the ProStar has also been optimized for service. In fact, the truck builder claims this adds up to 59 fewer visits to the shop over a 10-year life, contributing to its lowest-cost-of-ownership objective as well as to vehicle uptime.
From a technician's point of view, the swing-down front bumper and the removable side skirts are a plus. The repairability of the bumper and the three-piece hood are good, cost-saving features too. I'm not so certain about the big, one-piece windshield. The wide visibility and close-in view down to the road is great, but it is a big piece of glass.
Air and electrical connections at the back of the cab can be reached from the ground, and check and fill points under the hood are certainly easy to get to with the swing-down bumper.
Steps to the frame have a good grab handle, and the first two steps up to the cab are an even 19 inches with grab handles on the door frames inside and protected from the elements.
I came back to the ProStar with high expectations and was not in the least disappointed. It was just as good – even better – than the prototype I drove a year ago. It is formidable competition to the other premiums in the marketplace and will likely bring a lot of conquest deals.
Undoubtedly, ProStar is a great truck and, especially in this pretty red Limited edition, very attractive. And here beauty is far more than skin deep, because the truck is all-new, well thought out and well executed. It is a driver's truck for its quietness and handling, and it's an owner's truck for its low maintenance and repairability.
Test Vehicle Specs
Tractor International ProStar Limited
Frame 120,000 PSI 367.4" OAL
Engine Cummins ISX-485 - 500HP @1800 rpm, 1,650 lb.ft @ 1200 rpm
Clutch 15.5" 2-plate Eaton Solo clutch 7 spring
Transmission Eaton Fuller RTLO-18913A 13-spd w/dbl&od
Drive Axles Meritor RT40-145 40K TANDEM
Axle Ratio 3.58 to one
Rear Suspension International Air Susp. 52" spread
Front Axle Meritor MFS-12-143A 12,K wide track
Front Suspension Parabolic Taper Leaf 12,000#
Steering TRW PCF 60 power
Front Meritor Q-Plus 15 x 4 Drums
Rear Meritor Q-Plus 16.5 x 7 drum with MGM park on rear
Wheels Polished International 8.25 x 22.5
Front General 295/75R22.5
Rear Goodyear 11R G372
Fifth Wheel Fontaine SL6ATB675024) Air slide
Fuel Tanks Dual 26" 125/150 gal aluminum
Cab International 73-in ProStar
Hood Fiberglass tilt, 3 piece
Cab Aero Options Aero hood & bumper, chassis fairings, roof fairing and extenders, aero mirrors
Cab Interior Trim Limited
Seats International (National) 2000 1HP and 197
Sleeper 73" Hi-Rise
Paint Red Pearl Metallic
Front bumper chrome & body color, 2 pc; 18.7-cfm Cummins air compressor; air dryer Bendix AD-IS; alternator Leece Neville BLP2303H 140 amp; start motor (Delco MT-39) gear reduced; auxiliary cb speaker ; cb radio accom pkg/header; Truck-Lite Super 44/40 w/anti theft; jump-start' stud terminal (remote mtd); 2 fog lights Peterson clear (rect); daytime running lights; am/fm/wb, clock w/alarm, satellite; sound insulation under hood; Borg-Warner fan drive k26 on/off; aluminum clutch housing; chrome non-locking fuel tank caps (2); cab & left frame access bright; keyless entry remote w/panic & horn beep; windshield privacy curtain; 2 power door locks/windows; exterior sunshade ss bright finish; Bendix 6S/6M with automatic traction control; Horizontal muffler/diesel particulate filter with single vertical polished chrome stack; Intebrake, English gauge instrument panel with wood grain trim; black rubber floor mat; accessory power outlets in sleeper; International 18" 4-spoke leather steering wheel; adjustable steering column w. telescoping tilt
Step Heights 19/19.5/14
Floor height 52.5
Baggage liftover 53
Frame ht @ fifth wheel 41
Shoulder width 76
Windshield width 76
Height at standup point 76
Seat to ceiling 54-59
Belly room 11.5-32.5
Legroom (driver) 26-34
Footwell width driver/passenger 24 ea
Walkthrough seats 21
Height at bunk 80
Bunk to ceiling 57
Bunk width 42
Clear floorspace Not measured
Closest sight to ground 14.66'
Noise at idle 57 dB (A)
max accel 68
RPM @ 60 mph top gear 1250