Unless you're a Dodge dealer, you may not have thought much about this, but while the sport-utility vehicle has gone from walk-on to franchise player in the North American sales game, Dodge has fielded a team of only one SUV. With four SUVs sporting the Ford blue oval, five wearing the Chevy bow tie, and a sixth soon to suit up for Toyota, one looks like a lonely number indeed.

One thing that's held Dodge back is the company's internal brand bible, a set of rules designed to protect the integrity of its brands. But with the arrival of Dieter Zetsche, old assumptions began to be challenged. "Dieter Zetsche raised a bunch of questions," says Jim Hall, vice president of industry analysis for Auto Pacific, Inc. "In the auto industry in the twenty-first century, having these great rules about protecting your nameplates is noble. But if you're not in business, you will have no nameplates to protect."

And so we've seen some of the old rules at DaimlerChrysler fall away. We saw a Mercedes engine in the Chrysler Crossfire and other Mercedes components in the Chrysler 300/Dodge Magnum. Chrysler executives have allowed that some future Jeeps will not have the capability to tackle the Rubicon Trail, previously a Jeep must. The new Dodge Nitro smashes another heretofore sacred tenet: that a Jeep platform can never be shared with another division.

The Nitro, a burly concept that made its de-but at the Chicago auto show, was derived from the Jeep Liberty. This is the first sharing of a Jeep platform with a non-Jeep vehicle. (As for its concept status, make no mistake. The vehicle in these pictures may be a show car, but whether or not it's called Nitro, we fully expect this Dodge SUV to roll into dealerships in 2006.)

Compared with the Liberty, the Nitro's wheelbase has been stretched 4.o inches, and the vehicle is 4.4 inches longer overall. The Dodge is an inch and a half wider, but its roofline is an inch lower. The rejiggered dimensions give the Nitro a stance that is low and squat, whereas the Liberty's is more tall and narrow. This provides an important basis of differentiation even before the completely new styling comes into play. While the Nitro's proportions bring to mind the Hummer H3, its design details owe something to the Land Rover LR3. Sizewise, though, the Nitro is very close to Nissan's new Xterra.

Although the Nitro, unlike the smaller Liberty, is a true mid-size, it's still strictly a five-seater. But while there's no third-row seat, the stretched wheelbase allows for comfortable accommodations in the second row. Despite the squat roofline and narrow windows, headroom-front and rear-is adequate, and visibility is actually fairly good. The concept's seats are black leather with bright red mesh cloth inserts. The white-faced gauges are set in three chunky, matte-silver surrounds, and more matte-silver trim is splashed over the center console, home to a seven-inch nav screen and a meaty shift lever. In back, the cargo floor slides out for easier loading and unloading.

Mechanically, the Nitro is pure Liberty. So it is that under the show-car skin we find a control-arm independent front suspension and a live rear axle, albeit with a wider track front and rear than in the Jeep. We also find a 3.7-liter SOHC V-6, whose 211 hp and 235 lb-ft of torque are unchanged from its application in the Liberty (or in the Grand Cherokee, where it is the base engine). The V-6 teams up with a four-speed automatic and full-time four-wheel drive. With Chrysler figuring the Nitro's curb weight at 4115 pounds (or about as much as a Liberty with Kate Moss behind the wheel), the company estimates the 0-to-60-mph sprint at 9.6 seconds, the quarter-mile in 16.9 seconds, and a top speed of 108 mph, figures that are respectable in this class but unlikely to win the former Calvin Klein supermodel any races.

With the Dodge Durango having graduated from a biggish midliner to a no-kidding-folks full-size, there's certainly enough space in the division's lineup to drive a mid-size SUV into. We think the Nitro not only looks great but is different enough from its Jeep sibling that this bit of internal rule busting will help Dodge far more than it will hurt Jeep.