– General Motors Corp. is boosting fuel economy for full-size pickups and SUVs by as much as seven percent by making them lighter and more streamlined. Mechanical and aerodynamic changes and the cut in weight will help models including Chevrolet Silverado pickups improve to 15 miles per gallon in the city and 21 mpg on the highway, a 1-mpg gain, GM said. They’ll carry an XFE badge, for “extra fuel economy,” and go on sale next quarter, according to www.bloomberg.com.

The new designs for the Silverado and GMC Sierra pickups and the Chevrolet Tahoe and GMC Yukon SUVs save weight by using more aluminum parts and trim fuel consumption with tires that produce less friction on the road, GM said. The largest

automaker lowered the vehicles’ suspensions and made body changes to cut wind resistance.

GM also is adding hybrid versions of the Silverado and Sierra, which will join gasoline-electric variants of the Tahoe and

. GM hasn’t released pricing for the new models, and it didn’t say how much weight was shed in the redesign. 

The pickups will have the same towing capacity as the non- XFE versions, while the SUVs’ limit is slightly higher because of new transmission-cooling technology.