2007 Chevrolet Tahoe LTZ

With spiking fuel prices, an onslaught of import competition, hurricanes, and a spotlight on hybrid and crossover alternatives, the full-size truck market--traditionally the source of most of GM's profits--has been hard hit. Several models in the company's full-size range have experienced double-digit sales losses (in some cases 40-percent monthly sales declines) compared with last year. And the incentives just to move the iron are large and expensive.

To its credit, the General saw the impending problems early in the development process of its upcoming full-size sport/utilities and pickup trucks, which are based on the all-new GMT900 platform. Insiders said the new SUVs had to be considerably better than the current segment players if GM wanted to maintain dominant share position. As incentives disappeared and employee discounts lost their charm, GM knew it needed to get its new truck platforms into the market--fast.

It was 24 short months ago when GM pulled the GMT900's production schedule forward almost six months for a January 1, 2006 on-sale date. Most companies delay introductions due to unforeseen plant problems or technical difficulties; the reverse is often risky. Beyond showing confidence in the team that put these trucks together, it reveals that GM is pinning hope on the new platform that spawns the Tahoe and Suburban, along with GMC and Cadillac variants. Can a single SUV architecture save a company's profits at a time when its most viable segment is shrinking?

A first-drive smack-down test on the track and in the field reveals that GM brought game.

The old Tahoe was about as aerodynamic as a brick, so major work went into this area. There's a noticeable change in proportions: The windshield glass has more slope, the front end is reshaped, and the grille and bumper now work as a single aero-designed unit with few panel gaps. Likewise, changing the rear-end aero, smoothing out the mirrors, and lowering the airdam improved the overall drag of the full-size SUV by almost 12 percent--that means increased fuel economy. But fuel ratings have been bettered in other important ways, too.