General Motors has released the first fuel-economy information for its new 2015 Chevrolet Colorado and GMC Canyon mid-size pickup trucks.

So far, however, it includes EPA fuel-economy estimates only for models equipped with the 3.6-liter gasoline V-6 and six-speed automatic transmission. That engine produces 305 horsepower and 269 pound-feet of torque.

With that one specific powertrain, both the Colorado and Canyon achieve 21 mpg combined (18 mpg city, 26 mpg highway) with rear-wheel drive, or 20 mpg combined (17 mpg city, 24 mpg highway) if you order four-wheel drive.

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While they are smaller than full-size pickups, the Colorado and Canyon are still fairly large vehicles, and these fuel-economy ratings demonstrate that.

The numbers are only slightly better than those of the 2015 Chevy Silverado equipped with a 4.3-liter V-6 and six-speed automatic.

2015 GMC Canyon live photos, 2014 Detroit Auto Show preview

2015 GMC Canyon live photos, 2014 Detroit Auto Show preview

With either rear-wheel drive or four-wheel drive, that full-size truck only loses 1 mpg in the combined category and 2  mpg in the highway category to its smaller siblings. All of the trucks achieve identical city mpg.

Granted, GM has only released figures for the biggest, thirstiest engine available in the new mid-size trucks.

At launch, the Colorado and Canyon will come standard with a 2.5-liter four-cylinder gasoline engine, rated at 200 hp and 191 lb-ft of torque.

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This engine will also be paired with a six-speed automatic transmission, although a six-speed manual will be offered on spartan Work Truck models aimed at fleets.

For the 2016 model year, a 2.8-liter Duramax diesel four-cylinder engine option will also be available--making the pair the smallest diesel trucks on the market.

It won't go on sale until next year though, while the gasoline Colorado and Canyon models will arrive in dealerships this fall.

Prices will start at $20,995 for the Colorado and $21,880 for the Canyon, or about $5,000 less than a full-size equivalent.


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