No Lift 1998 Jeep Wrangler TJ Rear Tires Fitting - Part 2Posted in Project Vehicles on July 17, 2006
In Part I of this story (March '05), we undertook the seemingly impossible and often ill-advised task of fitting 35-inch Mickey Thompson Baja Claws under an unlifted Wrangler. We installed a Rock Crawler Hood from 4 Wheelers Supply, an Optima BlueTop Marine Deep Cycle battery lying on its side, and two of our 35-inch meats. In this part of the story, we'll show you how we made room under the rear of our TJ for the other two Baja Claws. We'll also take it wheeling to see how it all works on- and off-road.
MAKING ROOM FOR THE REAR TIRES
Fitting massive meats in the back of an unlifted TJ Wrangler requires a few tricks. The first problem we ran into with the 35-inch tires was the front portion of the rear wheelwell. The 35-inch tires will rub here at full flex. This area of the tub, just behind and below the base of the front seats, is full of tire-chewing pinch welds. It's also important to the structure of the tub and factory rollbar mounts, so you can't just cut it all out. To get around this problem, our plan was to move the rear axle of the TJ back 1 inch with a set of upper and lower JKS Manufacturing adjustable control arms that we ordered from 4 Wheelers Supply. By adjusting the arms to 1 inch over the stock control-arm length, we can move the axle back and prevent tire contact with the structural area of the tub. We also gain a bit of extra wheelbase. However, if you go too far the axle will hit the gas tank. There is still about 1/2 inch of clearance between our Dana 35 rear differential cover and the factory gas-tank skidplate. We've seen some lift kits allow the axle to rub here at full jounce. If your TJ has the Dana 44 rear axle, you might not have enough room to move it back a full inch, but we'd bet 3/4 inch would probably be enough to keep the rear tires out of the forward part of the wheelwell.
With the rear axle moved backward, we trimmed the back of the wheelwell where there is much less metal to cut out and less chance of compromising the body tub's structural integrity. The 1-inch-longer wheelbase effectively moves the Jeep's center of gravity forward a little and should help us get up any steep climbs we come across. Combining this with the fact that our Jeep sits 4-7 inches lower than other TJs with 35s makes for a stable climber.
While completing the rear-axle move, we noticed the factory rear track bar was binding throughout the suspension travel. On a hunch, we flipped the stock track bar upside down, which cleared up the binding problem. We thought that this might cause the track bar to hit the floor of the Jeep, but we cycled the rear suspension without the springs or shocks in place and the track bar didn't hit.
With our 35-inch Mickey Thompsons mounted on wide 15x10-inch Mickey Thompson M/T Classic Locks, we have quite a bit of tire sticking out from the sides of our TJ (originally we planned on using 15x8 wheels with 358 backspacing). We rectified this slight problem with some seriously trimmed stock fender flares out back. We enlarged the wheel opening on the flares by trimming about 3 inches from the inside and outside edge of the flares so they were almost flat, with just a slight edge that curls around. To mount our trimmed flare, we moved it up a few inches and back about 1 inch to compensate for the more rearward-mounted axle. Trimming and reusing the stock rear fender flares keeps the Jeep looking clean by covering the factory-stamped body holes and any cutting irregularities we caused when we hacked the sheetmetal with our OJ-like jigsaw skills.
Tires And Wheels
Now that we had room for bigger tires on our TJ, we knew that we wanted some serious meats and wheels underneath. We were hoping for a set of bias-ply mud tires for on-the-trail strength. We also wanted a wide tread for extra traction and sticky soft rubber to keep our lowrider Wrangler holding onto the rocks with authority. We decided that a set of Mickey Thompson Baja Claws was just the ticket. The sidewall specs are 35x13.50-15 LT, which gives us the 35-inch height we were looking for and a little extra width. They stuck to the rocks on our test run and dealt with a little bit of Southeastern mud with ease. These tires would never fit on the factory Jeep 15x7 wheels, so we looked into a set of 15x10-inch Mickey Thompson M/T Classic Locks. They have a backspacing of 3 5/8 inches, which helps keep the tires from rubbing too much on the control arms, coil buckets, or frame. They did rub the front sway bar, but with the Jeep so low and balanced, we ditched our front sway bar without noticing any horrible side effects.
The M/T Classic Locks are not real bead locks. They are street legal and come with changeable aluminum polished rings that can be swapped inexpensively for blue, black, red, or gold rings. We went with a set of blue rings and they look great. These decorative rings are bolted to a super-thick machined outer lip. We like the strength of the outer lip for trail bashing, but if you are going to hit the rocks, you should take the outer decorative rings off because they don't like being rubbed against anything hard. If you do damage the rings, they are easy and inexpensive to replace.
From Behind the Wheel
After some off-road testing, we found we needed to lower the rear bumpstops 1 inch to keep the tires from getting sliced on the trimmed rear wheelwells. We made our bumpstop extensions from some heavy-wall tubing and welded them into place. The other option was to simply purchase some extended urethane bumpstops from nearly any off-road shop.
Mostly stock suspension makes our 35-inch-tire-clad Wrangler drive on-road like a stock Jeep. It's not too bouncy or tippy, even though we ditched the front sway bar. Our only major problem comes from the lack of horsepower. Those four little squirrels in our TJ's 2.5L are hurting, and we need to regear the axles in hopes of ever using Fifth gear again. As for off-road, the Jeep drove up stuff that we didn't think was possible in our TJ. It scaled obstacles that are definitely not possible in a stock TJ or some overly lifted and unstable TJs we've seen. It drives to the trail comfortably and is a trail hero off-road. Keeping the factory-designed suspension geometry and adding larger tires makes for a very capable and stable TJ.
THINGS WE'D CHANGE
* We'd love to add a flatter belly skidder for more ground clearance.
* The slip-yoke on the back of the transfer case is still a weak point we'd like to get rid of.
* We'll trim the lower control-arm brackets a bit because they seem to get snagged occasionally.
* We'll add rocker guards.
* We might lift the front of the Jeep an inch or two to level it out. TJs come from the factory with the nose down. We've heard XJ springs add a bit of height to the Jeep, or we could install some lift pucks up front.
* The stock shocks work OK, but we'd like the added benefit and feel of some high-end monotube or adjustable shocks.