It's often hard to tell if a new model is a success after just a short time on sale, but a boost in production is usually a good sign.

General Motors is increasing production of the 2015 Chevrolet Colorado mid-size pickup truck, though it hasn't been able to match the Toyota Tacoma in sales so far.

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Chevrolet expects to sell all of the Colorados it can build, brand vice president Brian Sweeney told Wards Auto at last week's Chicago Auto Show.

Between November 2014 and January 2015, the Colorado and its twin--the 2015 GMC Canyon--racked up 16,937 sales, compared to 38,711 sales for the Tacoma.

2015 Chevrolet Colorado GearOn Edition, 2015 Chicago Auto Show

2015 Chevrolet Colorado GearOn Edition, 2015 Chicago Auto Show

While the GM twins are both brand new, the Toyota is a much older design. A refreshed version is expected to appear later this year.

Sweeney put the old Tacoma's sales lead down to a lack for supply of the Colorado and Canyon, expecting customers to materialize once the trucks become more widely available.

SEE ALSO: 2015 Chevrolet Colorado, GMC Canyon Four-Cylinder Gas Mileage: 21 Or 22 MPG Combined

That's why GM is adding a third shift at the Wentzville, Missouri, plant that builds the Colorado. Officials expect the truck to be "sold out" soon, Sweeney said.

He claimed Chevy is seeing a 41 percent "conquest rate" of new buyers coming over from other brands--but not any significant defection of buyers.

For January 2015, sales for both trucks totaled 5,942, with the Colorado accounting for 2,205 of those.

2015 Chevrolet Colorado GearOn Edition, 2015 Chicago Auto Show

2015 Chevrolet Colorado GearOn Edition, 2015 Chicago Auto Show

Both the Colorado and Canyon are currently offered with two engine choices: a 2.5-liter four-cylinder and a 3.6-liter V-6.

A six-speed automatic transmission is available in most models, although a six-speed manual is offered in the basic four-cylinder Work Truck. Rear-wheel drive is standard, with four-wheel drive optional.

MORE: 2015 Chevy Colorado, GMC Canyon Gas Mileage: 20 Or 21 MPG Combined For V-6

The highest fuel economy is mustered by the four-cylinder, rear-wheel drive configuration with the automatic transmission. It gets an EPA-rated 22 mpg combined (20 mpg city, 27 mpg highway).

For the 2016 model year, GM also plans to offer a 2.8-liter Duramax turbodiesel four-cylinder engine, which should boost fuel-economy ratings significantly.

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