JPFreek - Index

JPFreek - Spring 2008 - Index

Part II: Off-Highway Capability
The CTTVTC is really quite amazing. The off-highway areas were
actually created to be “re-creations” of famed areas in the United
States. An area known as the Rock Garden was actually designed
by Mark A. Smith, founder of Jeep Jamboree USA, to resemble a
portion of the Rubicon Trail in California. Furthermore, the Silt
Handling Circuit was designed to emulate the terrain at the Baja
500 and Baja 1000. Very cool!
With that said, we decided it was time to test the 2008 Jeep
Grand Cherokee CRD 4x4 Limited’s mettle as a “Trail Rated” Jeep
vehicle. Hill climbing and descent, Soft Terrain Traction, Water
Crossing, Mud Traction, and Trail Riding capability were all tested
in this segment.
One concern that we had with this vehicle from the get-go is
its low ground clearance. At less than 9”at the front axle and 10”
at the fuel tank, we had suspicions that the chance of bottoming
out during this portion of testing would be more than likely. This
was confirmed in the hill climbing and descent portion of our
testing.
Hill Climbing and Descent
The hill climbing and descent area at the CTTVTC features 3
different concrete surfaces, all designed to test tire traction in a
simulated environment with a 30’ long, 30° slope. Smooth
concrete emulates the granite in the Texas hill country and was
easy as pie to ascend with the vehicle’s easy-to-pull lever to
engage the Quadra-Trac II 4x4 system. However, upon descent
the departure angle was too much for the 9” front axle ground
clearance and consequently, the front bumper bottomed out
causing paint damage and a small crack. The irony is that the
departure angle was no more extreme than a driveway in a hillladen
suburb, reiterating the point that a 4x4 Grand Cherokee,
especially the Limited edition, should have suspension upgrades
available from the factory that are comparable to the new JK
Wrangler.
The other two concrete surfaces, one with a brushed surface
and the other with embedded rock, were no problem on the
ascent but again, the descent was a different story. A cool feature
of the 2008 Jeep Grand Cherokee 4x4 Limited (and not exclusive
to just the Limited model) is the Quadra-Trac II 4x4 system with
Hill Descent and Brake Traction Control. Essentially what the
system does is that with the push of a button, it engages torque
control that brings the vehicle to a crawl while descending
difficult slopes or wet terrain and manages the braking system
accordingly. This is a very nifty feature that compliments
off-highway situations.
Soft Terrain Traction
Maneuverability was pretty awesome in the Silt Traction Area.
Designed to emulate the terrain in Baja, California, the Silt
Traction Area was not only the highlight of fun while testing the
vehicle but also showed how capable the vehicle is in soft
terrain. We were especially surprised with the Goodyear Fortera
P245/60R18 tires. While they aren’t much of an all-terrain tire and
a model that we would not choose for a 4x4 Jeep vehicle, they
did handle surprisingly well given the terrain and lack of
off-highway tread design.
Water and Mud Traction
After a few laps in the Silt Traction Area, we were off to test the
water crossing capabilities of the vehicle. The conditions featured
a moderate rock bed with approximately 2’ of water at the
deepest point. With Quadra-Trac II engaged, the vehicle handled
the rocky water crossing rather easily and would most definitely
handle this sort of terrain better with a tire more designed for
all-terrain use. The same can be said from our mud traction
testing. The vehicle is certainly capable with Quadra-Trac II
engaged, but we kept wondering why a 4x4 Limited Grand
Cherokee has such puny looking tires. Again, more off-highway
upgrades from the factory would be very welcome.
Trail Riding
Testing wouldn’t have been complete without having an
opportunity to drive the vehicle in a real trail-ride simulation. The
CTTVTC features a Trail Ride Course consisting of 1.5 miles of
general trail-ride terrain. Suited for stock to extreme vehicles, the
trail-ride experience in the 2008 Jeep Grand Cherokee CRD 4x4
Limited was a good one.
Ground clearance was again an issue when approaching
several hills on the trail. We actually bottomed out on two
occasions, requiring winch help from our chaperone, Carson
Miller, and his wife. Other than this, the vehicle Electronic Stability
Program worked nicely and made the journey very enjoyable.