Gene’s Car Tips

Ford announced at the 2014 Detroit auto show that it would build the best-selling pickup truck in the nation with aluminum bodywork in 2015.

The reason: automakers are wrestling with a federal fuel economy mandate that calls for the nation’s new-car fleet to average 54.5 mpg by 2025. So more manufacturers will likely turn to lighter aluminum, high-strength steel and even superlight carbon fiber.

The equation is simple: Less weight equals less fuel burned. A cubic foot of aluminum weighs about one-third as much as a cubic foot of the steel traditionally used to build car bodies. The switch from steel to aluminum trimmed the F-150’s weight by 700 pounds—enough to boost a 3.5-liter, 6-cylinder Ecoboost F-150’s combined city/highway fuel economy average from 18 mpg to 20 mpg, according to Fueleconomy.gov.

European cars have been using aluminum for decades. Aston Martin and other makers of exotic cars for many years had aluminum body panels hand-formed by skilled “panel beaters.” Today, Aston Martin, Audi, Jaguar, Porsche, and Tesla, among others, have models with bodies made almost entirely of aluminum. Mercedes-Benz’s latest C-Class sedan is 200 pounds lighter, compared with the previous edition, thanks to extensive use of aluminum in its body.

Are there any downsides to aluminum? There are, aluminum can dent easily.

So Ford came up with a remedy making the body panels thicker than we did with steel—that is, we increase the gauge—but still save weight overall. We also apply a patented heat treatment during manufacturing to increase the strength of the aluminum.

Another concern is aluminum is more expensive in its raw state and in its fabrication than the traditional steel we’ve come to know in our cars’ bodies. However, if aluminum bodywork is scrunched in a collision, it can be very costly to repair, requiring more time, training, and special tools. And many body shops aren’t up to the task.

One Tesla owner on the Tesla Motors Club website describes a relatively minor fender bender not severe enough to set off air bags but that resulted in $20,000 of bodywork.

The new F-150 was designed so that smaller sections of, say, a rocker panel or floor pan can be replaced rather than having to replace the entire units, mitigating some of the extra cost.

Nevertheless, the higher cost of fixing aluminum bodywork could be reflected in higher premiums for the comprehensive and collision portions of your insurance bill.

In the long run, fuel savings may eclipse any higher insurance costs that aluminum-bodied F-150 owners might face. Or so Ford hopes.