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Jeep Wrangler Rubicon adds off-road gear to run tough trails
Bob Plunkett
Date Posted: 5/10/2005
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TAHOE CITY, Calif. -- High in California's Sierra Nevada Range, the Rubicon Trail -- rated Class 10 (out of 10) as most daunting four-wheeling trace on the continent -- scrambles over granite slabs and boulder-spiked sluices in the Desolation Wilderness, which stretches across the mountains from the village of Georgetown in the west to Rubicon Bay at Lake Tahoe.
Every summer the Rubicon lures drivers of four-wheel-drive (4WD) vehicles modified with heavy-duty off-road hardware to risk the metal steering a path through legendary sites like Little Sluice, Devil's Postpile and True Big Sluice, where boulder after bounder steps down a deep canyon to Rubicon Springs, mid-point of the trail and an overnight campground.
First navigated in 1953 by a Jeep, the Rubicon Trail serves as the ultimate test track for 4WD vehicles, drawing automakers with 4WD prototypes hoping to earn bragging rights with a successful crossing.
Engineers at Jeep put such stock in testing on the Rubicon that a block-long section of the Little Sluice, complete with tons of granite imported from the Sierras, has been re-created at the vast vehicle research facility of DaimlerChrysler in Chelsea, Mich.
So much experience running Jeeps across the Rubicon and the test-track version leads Jeep designers to create the ultimate dirt-dog trail vehicle outfitted with all the armaments needed to successfully scramble over walls of granite or slip down steep chutes on a Class 10 trail.
It's called, appropriately, the Rubicon.
As the newest model in Jeep's 2003 line, Rubicon amounts to a supreme off-road edition crafted from the rough-and-ready workhorse Wrangler wagon.
Wrangler, direct descendant of the original Willys MB "jeep" vehicle of World War II fame, has itself become an icon among 4WD enthusiasts, although to tackle serious trails like the Rubicon you would want to rig a Wrangler with after-market gear like locking differentials, special axles, skid plates and winches.
Rubicon installs all of the important after-market hardware needed for running the most difficult trails, but does so at the factory with all the extra equipment shielded by Jeep's warranty.
Particulars range from driver-selectable locking differentials fore and aft with Dana model 44 axles plus a low-range transfer case geared down to four-to-one ratio and heavy-duty drive shafts with 1330 universal joints.
When the transfer case is racked to low range and vehicle speed drops below 10 mph, a Rubicon driver may use a rocker switch on the dashboard to lock the rear axle and toggle on and off the locker for the front axle, all to enhance maneuvers on a dicey trail.
Then that transfer case adds the magic Rubicon needs to retard forward momentum to a snail's pace while also boosting torque from the engine and applying it directly to the four wheels so the wagon can creep over a trail obstacle inch by inch under the driver's constant control.
When not locked up, Rubicon's rear axle employs a torque-sensing limited slip designed to improve tire traction on pavement.
Rubicon rolls on five-spoke aluminum wheels capped by Goodyear Wrangler "Maximum Traction/Reinforced" tires with three-ply sidewalls and a chunky tread pattern wrapping around both sides.
The P245/75R16 tires measure 31 inches tall, which adds half an inch to the 10-inch ground clearance of Wrangler's stock 30-inch-high rubber.
There's also a progressive suspension system aboard and a strong ladder-frame chassis with generous angles of approach and departure necessary for moving into off-road recesses where conventional vehicles dare not tread.
Muscle for Rubicon comes from Wrangler's mega-torque Power Tech in-line-six engine with 4.0-liter displacement and a distributor-less ignition.
It delivers 190 hp at 4600 rpm and 235 lb-ft of torque at a low 3200 rpm, as directed through the stock five-speed manual shifter or an optional new automatic.
The new four-speed automatic, replacing a three-speed transmission, is also available on other Wrangler models, which include the SE, Sahara and Sport. The new tranny shifts quietly with smoother transitions and brings home better fuel economy figures.
To test the total package, we did what Jeep's testers do -- steer a Rubicon across the Rubicon Trail.
It wasn't our first time to run the Rubicon in a Jeep.
That occurred seven years ago using a Wrangler based on a design from 1987 that replaced Jeep's CJ series. While it performed automotive tricks mere cars could never conceive -- like stepping over walls of granite -- that Wrangler like the original Willys MB also jarred you senseless due to a suspension system comprised of leaf springs akin to the kind once used on a horse-drawn buggy.
By contrast, Wrangler today contains car-like coil springs in a design that enables a front wheel to travel up to 27 inches vertically before tipping the other wheel off the ground. As a result, it takes giant steps when crawling over obstacles yet still delivers an uncommon smoothness during rough runs, with no bone-crunching vibrations.
And the dashboard rocker switch on Rubicon for locking and unlocking axles brings revolutionary improvement in the way Wrangler handles the roughest terrain -- there's no lateral wiggle or hopping evident when inching over granite slabs, only direct linear progress with perfect control.
All Wrangler models are designed for versatility with convertible gear like a fold-down windshield, removable side doors and top plus a wash-and-wear cockpit.
Still, there are comforts aboard. Two bucket seats face a deep dash panel with dual air bags in place. A new design for the buckets adds 20 mm of track for rearward seat travel so even a long-legged rider fits.
Other Wrangler models for 2003 include the SE stocking as standard a new heavy-duty five-speed manual with synchronized reverse gear, the Sahara now with hard doors containing roll-up windows, and Sport equipped with foglamps and tow hooks in front.
Wrangler's base 2.5-liter four-cylinder engine has been replaced on 2003 models by a new 2.4-liter Power Tech four with 25 percent more power, ranking now at 150 hp.
Dark Khaki substitutes for Tan on a new three-ply Wrangler soft-top, with Dark Slate or Khaki available for the cabin shade and four new colors showing up as options for the body tint, including Bright Silver Metallic and -- on Rubicon -- Inca Gold Pearl Coat.
Wrangler supports a broad range of prices that begin around $16,000, with Rubicon set at $24,995 including the delivery fee.
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| Vehicle Specifications: |
| 2003 JEEP WRANGLER RUBICON Specs |
| Description: |
2-door sport-utility
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| Model Options: |
2-door sport-utility
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| Wheelbase: |
93.4 inches
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| Overall Length: |
156.1 inches
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| Engine Size: |
DOHC 2.4-L I4
OHV 4.0-L I6
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| Transmission: |
Manual/5
Auto/4
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| Drive: |
4WD
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| Braking: |
Power disc/drum/ABS opt.
Power 4-disc opt.
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| Airbags: |
2 (front)
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| Gas Mileage: |
I4 M/5: 19/20 mpg
I4 A/4: 17/19 mpg
I6 M/5: 15/18 mpg
I6 A/4: 14/18 mpg |
| Price: |
$ 16,000 to $ 26,000 |
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