It’s been a poorly kept secret that Ford’s next-generation fullsize F-Series pickups will rely on generous amounts of aluminum to reduce weight and fuel consumption.

And while Ford declines to confirm the next F-Series will be aluminum-intensive, a well-placed source says each passing day makes it less likely Ford can change course and stick with steel for the body-in-white, pickup bed and most exterior body panels.

Ford is spending tens of millions of dollars on manufacturing equipment intended for building the entire cab, including body-in-white and closure panels, from aluminum for both the new light-duty and heavy-duty pickups, the source says.

In addition, the bed will be aluminum for all F-150s but will be steel for the Super Duty trucks. Frames for all F-Series pickups will be made of steel.

The new pickups, slated as ’15 models, are expected to begin production in 2014, with the Dearborn, MI, plant leading the launch, followed by Kansas City and, for the Super Duties, Kentucky Truck, the source says.

After truck production begins, Ford’s fullsize SUVs will spring from the same platform, also integrating an aluminum body-in-white and closure panels, the source says.

Ford has been tightlipped on details about the new F-Series. The auto maker’s press conference on Tuesday, the second media day at the North American International Auto Show in Detroit, will feature the Transit and Transit Connect commercial vehicles.

But the venue for the press conference is not the Ford stand in Cobo Center. Rather it will be next door at Joe Louis Arena. A long, heated corridor is being constructed allowing journalists to walk from Cobo directly to the home of the Detroit Red Wings.

Ford declines to confirm if the new F-Series will be on display. But with the auto maker going to such lengths, a Joe Louis Arena unveiling for the brand’s most important marque, which has been North America’s best-selling vehicle for 31 years, would be fitting.

Adding to the intrigue is an off-site gathering place nearby on Congress Street where the auto maker will host NAIAS journalists and visitors, to be named the “Ford Truck Lounge.”

Converting the F-Series to aluminum raises numerous questions: How much more will an aluminum F-150 cost? How expensive will it be to repair aluminum body panels? With hundreds of pounds of mass removed, could a 4-cyl. engine provide enough motivation, even for towing?

Aluminum can cost auto makers up to $2 per pound, compared with $0.30 to $0.50 per pound for steel.

Alcoa, the world’s largest aluminum producer, declines to discuss the F-Series program or confirm its use of aluminum.

But spokesman Kevin Lowery says aluminum suppliers have been expanding capacity to serve the auto industry’s growing demands.

By 2025, the use of aluminum will increase from an average 343 lbs. (156 kg) per light vehicle currently to 550 lbs. (249 kg), according to Ducker Worldwide.

Lowery says a fuel-economy gain of up to 7% can be achieved for every 10% in a vehicle’s weight reduction. Ford has said it intends to take up to 700 lbs. (318 kg) of mass out of its next-generation trucks.

Last spring, Alcoa broke ground on a $300 million expansion of its aluminum sheet and plate plant in Davenport, IA. The world’s widest rolling mill is so large it occupies a second city as well, neighboring Riverdale. The first coils should roll off the line later this year.

Lowery says most of the new capacity, dedicated for automotive applications, already has been booked as part of multi-year contract agreements.

“Auto makers are driven by a desire to make cars more fuel-efficient, safe and durable,” Lowery says. Aluminum-intensive vehicles are gaining traction, from the Jaguar XJ and Audi A8 to models launched more recently such as Tesla’s Model S and the world’s first all-aluminum SUV, the redesigned ’13 Range Rover.

Some hardcore truck customers may question whether aluminum, which can cut weight as much as 50% compared with steel, can provide the same durability, especially in the bed.

Lowery says an aluminum pickup bed could be highly rigid and that aluminum “is probably one of the most durable materials in the world,” used extensively by the U.S. military in the Bradley Fighting Vehicle and MRAP (Mine-Resistant Ambush Protected) vehicle.

He also refers to the aluminum-intensive “FED” Fuel Efficiency Demonstrator military concept vehicle, which Alcoa and engineering partner Ricardo helped build.

“Don’t you think the U.S. Army would build their vehicles from some of the most durable materials in the world?” Lowery asks. “Aluminum is light, strong, durable and infinitely recyclable.”

Asked whether an aluminum pickup bed would need a protective plastic liner, Lowery scoffs. “They don’t have liners on Bradley Fighting Vehicles, and they don’t have liners in Humvees. Aluminum is used in blast shields underneath vehicles to protect the troops. This stuff saves lives.”

Crosstown rival General Motors is launching all-new fullsize pickups this year that also will take advantage of aluminum’s lightweight properties. For instance, engine blocks and hoods are aluminum, as are front suspension components in some models.

But GM opted for high-strength steel for frames and cab structures for the new trucks. “We know how to get the most out of it, and we know it will stand up to the tough treatment that truck customers can dish out,” GM spokesman Tom Wilkinson says.

Sticking with steel also keeps pickups more affordable, he says. “Last time I looked at the economic data, middle-class buyers weren't getting any richer.”

Wilkinson admits the divergent paths for GM and Ford will make for interesting times in the market. “Not in 100 years have the major truck makers staked out such different strategies,” he says.

tmurphy@wardsauto.com