TRAVERSE CITY, MICH. — BMW AG's redesigned 2016 7-series sedan required a long list of weight-saving techniques to drop 290 pounds from its previous-generation weight.
Those included switching to lighter-weight tires, adopting a new vehicle acoustics material that weighs less, changing suppliers where necessary to find lighter solutions, and even redesigning parts that BMW had already previously redesigned to cut weight.
“You need quite a large toolbox,” says Florian Schek, BMW head of lightweight design and vehicle weight, speaking to an audience at the Center for Automotive Research's Management Briefing Seminars Aug. 3 in Traverse City.
“We're heading for technological leadership and also in vehicle lightweight design concepts,” Schek says.
A key part of the new formula for the sedan, which debuts this fall, was the introduction of mass-produced carbon-fiber body components — a technology BMW embraced to construct its new i8 and i3 electric cars.
Using carbon fiber on the body structure resulted in a weight savings of 40 kilograms, or 88 pounds.
BMW has been saying in recent years that its foray into carbon fiber was not merely to make its EVs possible, but to open the door to mass-produced carbon-fiber content across the automaker's product line.
But Schek says BMW does not intend to rely on the lightweight material as its only weight-saving technique, and remains optimistic about steel solutions.
“There is no dogma at BMW regarding materials,” Schek says.
Schek said the sedan dropped another 88 pounds in components around the wheels, axles and brake areas.
It cut 22 pounds from the weight of acoustic materials throughout the cabin, trunk and engine compartment.
And it trimmed about 132 pounds out of a varied parts list that included seats and air conditioning parts.
It was necessary to reduce weight beyond its final target in order to compensate for more than 150 pounds of new weight that BMW needed to add to the car to satisfy safety and regulatory requirements, Schek says.