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Picture the giant skeleton of a dinosaur in a museum: The skull sweeping low as if feeding, the neck and spine rising high into the air before dropping with bony protrusions to the roughly segmented, curving tail.

Now picture this same formation as a tortuous and rocky path, climbing and twisting high over the California High Sierra west of Lake Tahoe. This is the fabled Rubicon Trail — it’s dangerous, tricky, dusty, slippery, and marked by rocks and ruts. One mile an hour can be considered making good time on the Rubicon.

We’ve come here to test the latest versions of what is arguably the most identifiable Jeep, the new Wrangler. And we start with the most rugged of the Wrangler line, the 2007 Rubicon, a Jeep that earned its bones on this treacherous landscape.

“Relax and let the vehicle do the work,” Mark Smith, an off-road expert known as Mr. Rubicon Trail, told us before we set out in low-range four-wheel drive. Easier said than done, since a driver often must use brakes and gas at the same time while negotiating rocks and ledges. It’s also best to keep hands and digits outside the steering wheel spokes because the wheel can spin like a blender if the front wheels hit an obstacle just so. And it’s important to concentrate on every obstacle that dots the path, while trying to ignore sharp drop-offs at the trail’s edge.

All of this adds up to work for the driver. But Smith was correct when he told us the new Jeep does most of the work. A remarkable bit of power, tactile scratching and clawing, and controlled sliding highlights its performance.

The new Wrangler comes in two- and four-wheel-drive editions: Wrangler X, Sahara, Rubicon, and Unlimited versions of each. And for the first time there is a four-door Wrangler available. Base prices range from around $19,000 to about $30,000.

In redesigning the storied Wrangler line up, Jeep has made an effort to improve its already solid off-road capability even as it made the vehicles more road friendly. The stated mission was to please purists and capture a new audience that might be drawn to competitors such as Toyota’s FJ Cruiser, Hummer H3, or Nissan Xterra.

According to Jeep’s Mike Donoghue, focus group s told the company they wanted “more of everything, but they didn’t want us to change everything.”

But the changes it made were good ones.

First, the new Wrangler is taller, wider, and has a longer wheelbase than previous editions. In fact, the four-door model is so much longer it loses a bit of its maneuverability in tight quarters off-road. Three-point turns were sometimes needed to negotiate corners around rocks and trees that the regular Wrangler made with ease. Nonetheless, it went virtually anywhere the two-door was able to travel.

The key to the heart of the new Wrangler is its new, more powerful engine. It’s a 3.8-liter V-6 with 237 lb.-ft. of torque for steady crawling, and 202 horsepower for silky-smooth road travel. A stiffened frame and body package add to the smoothness and benefit off-road driving as well. They help the car hold firm while the work is done by free-traveling underpinnings that include a nifty front sway bar that can be unlocked electronically, providing the extra wheel travel critical for crawling up and down obstacles.

Toss in the latest upgrades to Command-Trac and Rock-Track transfer cases and electronic axle locks and you have a Wrangler that feels more sure-footed off-road.

Jeep says that 60 percent of its buyers actually go off-road — something most other SUV drivers rarely do.

The engine is hooked up to either a four-speed manual or six-speed automatic transmission. Jeep also is offering an electronic anti roll program and stability control.

Even as Jeep looks for new customers, it has managed to retain its essence, burying it deep within the electronic and mechanical improvements under a familiar shape.

Outside, I like the move to small plastic fenders (with fog lamps leaving the fender-fronts and dropping into a recessed lower fascia for protection). If you are going to do any serious, tight, off-roading, this new design feature will save you money someday.

Inside, if you’re going to go off-roading, you will wish Jeep had put overhead handholds for front and rear passengers. Rocking and rolling sometimes requires extra grip — inside and out.

THE BASICS
Base price/as tested: $19,000-$30,000 various base prices
Fuel economy: 17 miles per gallon (est.)

THE SPECIFICS
Drivetrain: Four-wheel drive (two-wheel drive available)
Seating: Wrangler/Unlimited four-door four / five
Horsepower: 202 Torque: 237 lb.-ft.
Length: Wrangler/Unlimited 152.8/173.4 inches
Wheelbase: Wrangler/Unlimited 95.4/116.0 inches
Height: 70.9 inches
Width: Wrangler/Unlimited 73.7/73.9 inches
Curb weight: Wrangler/Unlimited 3,760 -4,129 pounds /4,075-4,340 pounds

Royal Ford can be reached at ford@globe.com.