GM eyes the mpg crown for revamped Suburban, Tahoe

DETROIT — One goal of the redesigned Chevrolet Suburban and Tahoe coming next year is to lock down General Motors' fuel-economy leadership in the full-size SUV segment.

For the first time since the 1990s, the Suburban and Tahoe will be available with a thrifty diesel engine — a 3.0-liter turbocharged inline six-cylinder.

That engine launched this year as an option in the Chevrolet Silverado 1500, along with a 10-speed automatic transmission. It makes the big Chevy pickup the most fuel-efficient in its class, with an EPA rating of 23 mpg city, 33 mpg highway and 27 mpg combined.

The same powertrain is now headed to the new Suburban and Tahoe and will be the only diesel offered in the segment.

Chevrolet executives say the turbodiesel will give the SUVs some of the highest fuel-economy ratings in the segment. To get there, the GM vehicles will have to beat the 17 mpg city, 24 mpg highway and 20 mpg combined rating of the current leader, the Ford Expedition.

Most other competitors in the segment, such as the Toyota Sequoia, have fuel-economy ratings in the mid to high teens. On the current Suburban, the most fuel-efficient version is EPA-rated at 14 mpg city, 23 mpg highway and 17 mpg combined. To hit GM's target, the redesigned vehicles likely will reach 25-30 mpg highway.

The new Suburban and Tahoe arrive at dealers next summer. They've grown in size and weight over the outgoing models, making it tougher to hit the coveted 30 mpg on the highway. The current Suburban checks in at between 5,600 and 5,800 pounds — considerably heavier than the Silverado, which weighs 4,500 to 5,400 pounds.

GM released some specs on the coming Suburban and Tahoe, but not curb weight or fuel-tank size.

The current Suburban has a 31-gallon fuel tank. If the 2021 model has that same size tank and gets 25 mpg highway, it will be a real long-distance cruiser, able to go nearly 800 miles between fill-ups. The 3.0-liter engine is rated at 277 hp and 460 pound-feet of torque.