Western Star’s 5700XE might just be everything to everyone. It’s a big Classic-styled truck, but with second-to-one <<one is the correct word>> aerodynamics. The company claims the 5700XE is 14% more aerodynamic that its predecessor, the 4900, and the second most aerodynamic truck in the Daimler Trucks North America stable, next to the Cascadia. By combining cutting edge aerodynamics with a high-efficiency powertrain, Western Star gives its customers the styling they want with the fuel economy they need to make money.
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 were design priorities on the project. Chief Designer Don Vena incorporated all those elements in the 5700XE, but pulled them forward with more contemporary styling.
While the 5700 may look a little different — a lot different, really — on the outside, it’s still a Western Star underneath. It features the same big comfortable cab its owners are familiar with. It’s solidly build, but not terribly heavy. It tips the scales at just 19,000 pounds full of fuel.
The Ultimate Test Drive team had the truck for a full day when it was launched in September 2014, so we ran it about 125 miles northwest of Las Vegas to a place called Rhyolite, Nevada to check it out. The trip to Rhyolite was on four-lane, Interstate-like US Hwy 95, so we got a taste of the truck’s on-highway performance. But Rhyolite itself is a gold-mining ghost town with cool scenery and some nasty roads and grades. The roads around Rhyolite are more primitive, so, steeper, twistier and more of a challenge to any powertrain.
The 5700XE is equipped with a fully integrated Detroit powertrain featuring, in this case, a DD15 engine rated at 400 hp and 1,750 lb-ft mated to a DT12 direct-drive automated manual transmission. The brain behind this really fuel-conscious setup is a new feature set called Intelligent Powertrain Management, known as DP15i that uses GPS and terrain-based mapping to give the engine a look ahead at the road it traveling on. It can accelerate before getting to a hill and throttle back as it goes over the top to use momentum and gravity to help conserve fuel.
As we demonstrate in the Test Drive video, the system performs as well as or even better than even an expert driver. The other three videos in the 5700XE series explore the truck even further, with a walk-around guided tour and a close look at some of its driver comfort and safety features. There’s also an interview with the truck’s Chief Designer, Don Vena. Check ’em out.