Not long ago it would have been a stretch of the imagination to use the words Western Star and aerodynamic in the same sentence. Today, they might be considered synonymous. The company claims its new flagship, the 5700XE, is 14% more aerodynamic than its predecessor, the 4900, and the second most aerodynamic truck in the Daimler Trucks North America portfolio, next to the Cascadia. Company officials did not elaborate on the spread between the two, but it’s probably closer than many would suspect.

In 2012, Western Star rolled out a first stab at an aerodynamic truck, the 4900 FE. It featured a set-back front axle and a rounded hood profile, a swept-back bumper and few other cosmetic changes. While it did cut the air a little more smoothly than the standard 4900, it fell short of the industry’s current definition of a true aero truck.

But the market was different in 2012. In fact, a year before the 4900FE hit the streets, Western Star conducted a customer survey that suggested 40% of its customer base was still on the aerodynamic fence, but were beginning to lean in that direction.

“Our customers told us they wanted distinct styling, and not something they associated with a fleet truck,” Western Star general manager Mike Jackson said when the 5700XE was launched in Las Vegas in September. “But that has changed in 2014. They tell us now that while the badge and the image are still important, they realize they have to make money too.”

Jackson noted that the current Class 8 tractor market is running at 65% full aero, compared to the traditional or partial-aero designs, like the 4900FE. That left Western Star without a truck to fill a growing market demand.

“Without a full-aero offering, we were clearly self-imposing some limitations on our growth opportunities,” Jackson says. “We realized we couldn’t play well in the aero market with what we offered. The 5700XE is the answer.”

Jackson says he expects this truck to push Western Star into the 5%-plus range for market share in the on-highway segment by opening the doors to that 65% of the on-highway market they couldn’t previously touch.

Western Star’s director of marketing, Ann Demitruk, says the 5700XE is not being aimed at large truckload fleets, leasing companies or customers that want the absolute lowest up-front pricing. Rather, she sees owner-operators, small- to medium-sized fleets, and fleets looking for a unique look and brand, along with fleets looking for a premium reward truck for their drivers as the target market for the 5700XE.

“We won’t sell a lot of these trucks to fleets looking for a low-cost, cookie-cutter truck,” she says. “We’re positioning this as a truck that will set the customer off from the competition while delivering top fuel efficiency and outstanding total cost of ownership.”

The design phase was an interesting exercise. Designers had an iconic brand and distinctive style to work with, which generally demands a light touch with the brush. The 5700XE’s chief designer, Don Vena, held many design clinics with top customers to ensure they’d be satisfied with the result, but he certainly left a bold stroke of his own on the truck.

“Western Star has always been unique, so I never wanted to deviate from that,” he says. “With the push for aerodynamics there comes the thought that it needs to look like a jelly bean. I just don’t see Western Star ever having that kind of vehicle.”

He says the design priority was maintaining the traditional Western Star proportions; the cycle fenders, the rectangular headlights, the raised center section on the hood, and, of course, the vertical grille bars and the sun visor. Vena incorporated all those elements in the 5700XE, but pulled them forward with more contemporary styling.

The rectangular headlights are still there, but now they are projector-beam lamps with LED brows and a three-piece modular design for lower replacement costs.

Two particular design elements contribute further to the styling, but also the aero performance, Vena says. The bumper end caps, he says, are absolutely necessary to the aero performance, routing the air around the front wheel well and over the top of the fender.

“Without the end caps, the aerodynamics just fall apart,” he says.

The sun visor, an essential part of the classic look, is also highly functional. It was designed to help channel air flow up and over the cab roof. It’s also aero neutral, which means the air doesn’t see it. “It contributes no drag at all,” Vena says.

And the truck is loaded with bright work and stainless steel trim, including the grille surround and the grille bars. Vena says that was non-negotiable in the design process.

“It’s a pride of ownership for these folks,” he says. “They love to have the bright work on the vehicle. While we were designing the side fairings and body molding we made provisions to be able to dress it up.”

I suppose if aerodynamics was the 100% prime focus of this design — or any truck design for that matter — you’d have a truck that looked like a jelly bean or an egg. That may be the optimum aero shape, but who’d really want to own a truck that looked like an egg? If the aero work on this truck is effective as its designers say it is, it’ll earn its keep. But when it comes to fuel efficiency, the aero package gets a lot of help from the proven Detroit powertrain.

Powertrain and safety features

Since the 5700EX will only be offered with a Detroit engine, a high degree of chassis and powertrain optimization was possible. Customers will have their choice of DD13, DD15 or DD16 engines and a choice of DT12 automated manual or several Eaton Fuller manual transmissions. The really fuel-economy conscious customer can opt for the integrated Detroit Powertrain with a feature set called Intelligent Powertrain Management.

This has a downsped DD15 engine rated at 400 hp and 1,750 lb-ft mated to a DT12 direct-drive transmission with IPM and either Detroit 6x4 drive axles with a 2.41:1 ratio, or a Detroit 6x2 setup with a 2.28:1 ratio.

“This is our entry into the down-speeding realm,” says Brad Williamson, DTNA’s manager of engine and component marketing. “We offer a higher torque engine with a lower axle ratio, which allows you to operate at lower engine rpm for better fuel economy.”

The torque and horsepower curves show the engine produces its best torque between about 1,000 and 1,300 rpm, and close to peak horsepower between 1,300 and 1,625 rpm. Williamson says customers who operate in rolling terrain will see the greatest benefit from this powertrain choice, while those running in flat or mountainous terrain may prefer a more traditional powertrain option.

“DP15i uses preloaded terrain maps and GPS to look out about three miles ahead and then, with the help of load and grade sensors, fuels the engine according to need,” he says. “Once you have the system engaged, the driver doesn’t need to touch the brake or the accelerator. The system is managing everything as efficiently as possible.”

Williamson says the IPM will be standard on all DT12 packages beginning in 2015.

At the launch event, Williamson said the new powertrain packages could net certain customers using the 6x4 or 6x2 configurations efficiency gains of up to 5.2% and 7.6% respectively, compared to a baseline powertrain consisting of a DD15 455/1,550, a 10-speed manual transmission, and a Detroit 6x4 with a 2.53: ratio. As is usually the case, he wouldn’t discuss pricing during his presentation, so it would remain with the buyer to hammer out the ROI potential at the time of purchase.

Western Star has also added a few safety and driver convenience features. A new wood- and leather-wrapped steering wheel has thumb control functionality for navigating the driver display menus as well as headlamp and marker lamp interrupt (if anyone still does that little courtesy), cruise control, phone pickup and disconnect, volume control and mute.

“It’s not just a lapped on system,” Jesus Gomez Director of Engineering at Western Star Trucks. “We worked with WABCO to calibrate their system for the particulars of the Detroit powertrain and our braking system, so it behaves as you’d expect a Detroit product to behave.”

5700XE first impressions

You can’t tell much from the inside about how the outside is doing from an aerodynamic perspective, except to observe the noise. Non-aero trucks are pretty noisy, and that’s just from the eddy of air and the buffeting that a big square hood sets up. The 5700XE was very quiet. I checked my iPhone sound meter app, and saw 72-73 db. That’s very close to passenger car quiet, and the same reading I got from a recent drive in a Kenworth T680.

I’ve written before on how I feel about the DT12 transmission, and can find no fault with it. It’s relentless in its pursuit of skip shifting opportunities and it never misses a chance to grab the next gear as soon as possible. On several trips up a 6% or so grade, I found the DT12 upshifting at 1,400 rpm, which depending on the gear, landed me back at 1,000 or 1,100 rpm. That’s courageous.

On the opposite side, downshifting for rpm while using the engine brake, several times I was able to manually get the thing as high as 2,300 rpm. There’s some serious retarding capacity there with a 15-liter engine.

I struggled a little with the OnGuard collision avoidance system, probably because I wasn’t entirely familiar with the way it works. It restricts vehicle speed to a prescribed following distance (a customer preset option), and while driving north west out of Las Vegas toward the town of Beatty, I found myself pressing down on the pedal and wondering why I wasn’t accelerating. Truth was, I was coming up behind a slower car or truck, and the system is designed to maintain a set following distance. Once I figured out that changing lanes removed the threat from the radar’s eyes, away I went.

OnGuard braked and throttled the truck in harmony with traffic. It could be a very useful tool for a poor man’s platooning arrangement.

While gentle in its speed and braking management in most situations, a couple of stray four-wheelers with the annoying habit of braking in front of a truck got the system’s attention — and mine too — pretty quickly and the braking was pretty aggressive when it needed to be. Otherwise, the system was virtually transparent to me.

I find the Western Star cab beyond spacious. And it still is. It’s the same steel cab that goes back to the Constellation days in the late '90s. Tried and true, I guess, with little to improve upon. I’d prefer dashboard switches were spaced out more, or grouped into functions. Maybe it’s because I get to drive one so infrequently, I fumble around a lot looking for the right switch. Someone with more time-on-type might not have a similar complaint.

The ride and handling are what you’d expect in a premium truck. For as large as it appears from the outside and from the left seat, it’s still pretty nimble. The tried-and-true Airliner suspension provides a very good ride. Our truck had wide-base single tires with full-width axles so it felt very stable, even in a stiff crosswind.

The mirrors produced my only negative observation, and it’s a modest one. They are cab mounted, which restricts the door opening to somewhat less than 90 degrees. Also, with the window open, I noticed a lot of wind noise from the mirrors. My guess is there’s still some aero improvement to be gained by moving the mirrors back onto the doors.

Western Star GM Mike Jackson says the 5700XE is targeted at the classic truck guy who knows that in trucking’s game of pennies, aero counts. We couldn’t verify the aero performance in a quantifiable way on our run. Jackson says it’s second only to the Cascadia in the DTNA portfolio in terms of aero performance, and I have no reason to doubt him. It’ll be interesting to see some actual numbers emerge as these trucks enter service in the spring of 2015.

Overall, I was quite pleased with the truck, and ewxcited about the downsped and highly integrated powertrain. It really does offer the "large car" crowd the benefits of driving a "jelly bean," without sacrificing style.