B.F. Goodrich All-Terrain T/A
KO Tires for the Jeep XJ
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B.F. Goodrich is our choice for both the Dodge Ram 3500 4WD Quad Cab and the '99 XJ Cherokee 4x4. Mounting
and balancing require a skilled shop. We turned to Purcell Tire & Rubber Company at Reno,
33" tires have been on this lifted Cherokee for seven years. Time for new tires on the six-inch lifted 4x4.
XJ Cherokee Dana 30
front axle and rear
Chrysler 8.25" axle each boast ARB Air Lockers and a 4.10:1 gearing
change. This Jeep 4x4 is a true trail-and-street, multipurpose machine!
Our tire size choice for the Jeep XJ Cherokee 4x4 has been LT285/75R-16. The old tires were Load Range E.
This time, we opted for Load Range D—and less stiffness. This is still over-capacity, an 8-ply rated tire
typically used on full-size pickup trucks. For this much lighter, 3,800 pound Jeep (curb weight with
aftermarket accessories in place), Load Range D is way beyond the vehicle's requirements.
Wheel rims are American Racing's ATX Series Mojave style in 16"x8" size with 4.48" backspacing. This
provides a desirable track width increase without the need for aftermarket fender flares. The vehicle performs
well off-road, and 2-inch wider than stock track width helps offset the higher center-of-gravity created by the
suspension lift. These Teflon-coated wheels have been thoroughly tested over the last seven years! Short
American Racing chrome valve stems offer maximum sealing yet have a short stem for avoiding off-pavement debris
Rim clamp style tire changer works best for alloy wheels. Although not a "European style" changer, careful
use of this equipment can mount these tires without damaging the Teflon coating. Experienced tire personnel are
your best assurance of tire reliability. Note short, metal valve stem's length, well out of harm's
Seating the tire beads against the rim edges assures a good tire seal and reliable service. At right is the
actual wheel weight requirement, excellent for a tire this size. New weights in place and zero balanced, this
wheel/tire will go to the front (steering) end of the vehicle for desirable handling and smooth ride quality
during initial run-in of the tires. Tires get rotated and re-balanced each 3,500-5,000 miles.
In the video, see how balancing and wheel runout are an important part of tire service. Wheels and tires
require periodic rotation and re-balancing, especially on Jeep 4x4s and Dodge Ram 4WD trucks with beam front
axles. At right, final torque of wheel nuts is set with a calibrated torque wrench—100 ft-lbs for this Jeep XJ
Cherokee's 1/2-inch wheel studs and nuts. Use correct nuts with alloy wheels; make sure the thread length is
Here is the OEM Jeep factory door sticker with recommended tire pressures—for the OEM tire size! Note that
33 PSI is for a P215/75R15 tire size. At right, new oversized tires reveal Load Range D with a substantially
higher load capacity per tire. These are true "truck tires". 33 PSI would likely be over-inflated on this
lighter weight vehicle.
Tire inflation pressure is critical. While each tire and vehicle application has different needs, we found
that the Load Range E oversized tires behaved best on-highway at 24 PSI on this XJ Cherokee 4WD. Anticipated
PSI for this Load Range D application will be 25 to 28 PSI. We started at 25 PSI and will increase the cold
pressure gradually to 28 PSI during tests. Weight distribution is fairly even, as noted with the OEM tire
pressure settings. Note the unique, curved tread design that helps compensate for caster/camber and a solid
beam front axle's steering geometry.
More than good looks, this is a functional and versatile vehicle. We have nearly 50K miles of testing on the
Full-Traction Suspension system, the wheel-and-tire package, ARB Air Lockers and the 4.10 axle gearing. With
the AW4 transmission and overdrive, one option would be the axle gearing choice. 4.56:1 might work better than
4.10:1, especially with the added 600-plus pounds of aftermarket bumpers, a Warn XD9000 winch and oversized
wheels/tires. Though not available, 4.27:1 ring-and-pinion gearsets would be even better!