Jeep - a never ending story: Tires and Wheels
So, today was the big test. After many modifications, the Lil’ Heep was ready for the big test. Or, maybe just another step in the pecking order of modifications.
To set the stage, what started as a basically stock 1994 Jeep Wrangler with over 100,000 miles had undergone numerous operations en-route to its current configuration. Now set with 4.56 gears, front and rear locker, 4 inch spring lift, 2 inch body lift, 4:1 transfer case, NV-4500 transmission, and several other after market modifications, the Lil’ Heep was set to hit the trails.
The final modification was replacing the 15 inch rims and 32 inch tires with a new combination. I have long ago opted to keep the stock axles and install upgraded internals. The stock Dana 35 internals were replaced with a Black Diamond full-floater axle shaft kit featuring locking hubs. The front Dana 30 was retained with the addition of the PosiLock kit to replace the stock central axle disconnect when engaging four wheel drive.
The wheel and tire package features 16 inch rims with 295x75R16 BF Goodrich All-Terrain’s. With a 33.2 inch tire height, this tire is slightly larger than the 33 inch (32.7 inches) and smaller than a 35 inch (34.7 inches) tires.
As this combination replaced 32 inch BFG Mud-Terrain's, a number of drivability issues were noticed. First, the AT tread design is significantly quieter on the highway. Second, steering was noticeably easier. At this point, it should be noted that the replaced tires were out of balance and showed excessive cupping of the tread probably the result of many miles on bent rims. So, what ever the reason, tires and wheels can make a significant difference in ride and handling.
The test course was the Gunslinger Trail in Corral Canyon OHV Area. In 2006, a major southern California wildfire (Horse Fire burned) through the Coral Canyon OHV Area. Aside from taking out about 90 percent of an adjacent wilderness ares, the Horse Fire took out about 70 percent of the OHV area. Key to that event is the majority of the 4x4 routes were in the 70 percent destroyed area.
Within months of the fire, Cleveland officials began fire recovery efforts with a projection that it would take up to five years before Corral Canyon would be open for use. In the ensuing months, the Cleveland officials did make serious efforts to use many sources to support Corral Canyon. Volunteer participation played a major part in the fire recovery efforts. Volunteer work parties would stage materials on weekends and Forest officials arranged for labor crews to install several hundred miles of fencing to delineate the trails and speed the opening of Corral Canyon. In May 2008, Corral Canyon OHV area was re-opened; over three years ahead of projections.
Today was the time for the Tierra del Sol Four Wheel Drive Club of San Diego to conduct their annual “adopt-a-trail” clean-up project and Gunslinger was the target trail.
Situated about 38 miles east of San Diego, the trip to Corral Canyon offered an opportunity to test the new tires in an extended highway situation along with an off-road situation.
I was pleased with the on-highway handling and reduced noise as compared to the Mud-Terrain thread pattern. As I drive an open-top jeep, reduction of tire noise is important. With the quieter riding radials, I was able to engage in radio conversation at highway speeds in an open-top jeep.
The trails at Corral Canyon are a mix of de-composed granite and areas of large granite slabs. The trails were dry with not soft sand sections. For the trail ride, I lowered tire pressure to 16 lbs. Trial and error with varying trail conditions will determine the optimum tire pressure for a given situation. For today, 16 lbs was sufficient.
Gunslinger features one section with steep drops and tight turns. Our direction was downhill. It was during this section the first of several issues became apparent.
The larger tire size changed the turning radius. Note for next tight turn trail, be prepared for a two or three point turn instead of a single turn. I noted rubbing along the frame. Time for tire stop adjustment. Also, time to re-evaluate the sway-bar quick-disconnects. Normal procedure calls for disconnecting the sway bar, tilting it up and securing it with bungee cords. That upward tilt now interferes with turning radius.
All too soon, the trail ride was over and it was time to air up and head home. Then, the final issue with larger tires was apparent. Four inch springs and 2 inch body lift are not sufficient for this size of tire. Under full shock compression, the rear part of the fender well does compete with the tire tread for space. The metal body panel is no match for the tough tire. Modest trimming of the rear quarter panel is necessary to eliminate metal to tire contact.
Overall, the new tires performed well and no tire performance issues were noted. The metal trimming and sway-bar positioning are easy fixes to accomplish. Then, owning a jeep is committing to one modification after another......
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