The highest-volume vehicle GM sells in North America is a full-size pickup truck—one that likely also contributes outsize profits from each of its hundreds of thousands of units.
So the launch of the 2019 Chevrolet Silverado Saturday night before the Detroit auto show was a big deal for the company.
Like every other new vehicle produced for a new model year, big thirsty pickup trucks have to deliver higher fuel-efficiency ratings at the same time they add new features and boost their capabilities.
The highest-efficiency version of this year's Silverado is rated at 20 mpg combined by the EPA, against 23 mpg combined for the Ram 1500 EcoDiesel (the highest-ranked 2017 pickup) and 22 mpg combined for the best 2018 Ford F-150.
We got only partial information on the 2019 Silverado line from Chevy last night; full details, ratings, and specifications won't start to arrive for three or four months.
But one spec we did get stood out: the 2019 Silverado is 450 pounds lighter than a comparably equipped 2018 model. That's huge.
2019 Chevrolet Silverado
The weight reduction, Chevrolet said, comes from extensive use of several grades of high-strength steel—they make up 80 percent of the truck's steel components—and GM's mixed-materials strategy.
While the competing Ford F-150 pickup has a fully aluminum body—including its cab and bed—on a steel frame, Chevy has mixed it up. All "swinging panels" (doors, hood, tailgate) are made of aluminum.
The frame, cab, and bed remain steel, with various individual structural pieces and running-gear components of other materials, including second-stage springs made of composite material—just as they are on the Corvette sports car.
The bed of the pickup is the "working end" of the truck, like the head of a hammer, said GM product chief Mark Reuss, who added a sly dig at Ford: "You wouldn't want an aluminum hammer, would you?"
As always, ever more sophisticated computer modeling allows big car companies to simulate their designs before a single prototype is built.
That modeling shows how the design will perform in a crash, and calculates where the design engineers can remove ounces and pounds from the structure.
Chevy's weight reduction of 450 pounds is exactly twice the 225 pounds Fiat Chrysler said it had removed from its new Ram 1500 pickup, the third of the three high-volume domestic full-size pickups.
2019 Chevrolet Silverado 'aero curtain' in front fender
2019 Chevrolet Silverado
2019 Chevrolet Silverado cab-roof spoiler
Along with lightweighting applied to every piece of its new pickup truck, GM has worked extensively on the aerodynamics of what is fundamentally a large, bluff, high-drag shape.
Rather than fit a full-size bed cover to reduce airflow turbulence inside a large open pickup bed, the Silverado's engineers spent thousands of hours on a very carefully crafted spoiler that sits at the back edge of the cab roof.
Its sole mission (beyond housing the high-mounted third brake light) is to lift the departing airflow over the open bed so lands at the back end, where another spoiler at the top of the tailgate smooths its path past the vehicle.
The final version, according to Chevy, produced a 7-percent reduction in drag. That's a major improvement in a discipline where tenths of a percentage count.
So-called aero curtains at the leading edges of the front sides pull air inside the fender and direct it past the front wheels to reduce turbulence in the wheel well.
Then there are powertrains, only a few details of which Chevy revealed.