|A TJ with Leaf Springs???||Short Cuts|
By: Paul Nasvik - 4/2000
|Brad stuck on flat ground.|
With all the hype about the Warn and ProComp coil kits for leaf sprung Jeeps, it's nice to see someone going against the grain. Think coil springs are all you need to turn your Jeep into a contender? Think again.
Enter Brad Kilby. Brad's put a lot of time into his TJ. He's changed his lift at least twice, added custom D44s front and rear, traveled the hardest trails California has to offer and rolled it once. This Jeep sees a lot of action.
|Mike takes the torch to the control arm brackets.|
|Cutting the TJ brackets off the Currie axle.|
|The old axle ready for the new install.|
|The upper shock mount is a hoop betweeen the frame rails.|
|The stock control arm hanger is on the left.|
The Jeep can also lift a tire when you hit the gas on the street. Put it on a steep rock face and it's downright scary! Wedge the passenger side tire against a rock (even a small one) and the driver's tire can get 2 feet in the air - simple sections of trail can defeat this "extreme" rig.
Why? There's a few reasons and they work together:
Currie calls it "jacking" and addressed it on their TJ's with triangulated upper control arms and by wrapping the lower arms around the rear axle. They did away with the trackbar altogether. Seems to work most of the time, but I saw them lifting a tire at the Warn Rock Crawling Championships. Everyone lifted a tire, of course, but this was distinctly the TJ thing - the driver's side tire just doesn't drop like it should.
Brad and I have talked about solutions to this for a long time as we have similar rigs. I should say...had similar rigs. Brad decided that the best way to make the TJ more predictable on trail would be to make it less like a TJ.
He put leaf springs on it.
Brad got together with Mike Duncan, the FourXDoctor, and took a bunch of measurements. They agreed that lengthening the control arms was going to be too much work for this single application. And if they did, it would take the Jeep down for at least a month while the kinks were worked out. On top of that, there was no guarantee that it would solve the problems.
Mike happened to have an extra set of National Springs laying on the floor of his shop. Jeeps have been using leaf springs forever - there's a vast pool of knowledge and parts to pull from and most of the problems associated with tall lifts have been worked out.
Out came the torch. After lifting the Jeep onto stands the gas tank was removed and the battery disconnected. Then the rear axle was dropped out and the control arm mounts were cut from the frame.
They grabbed a Scout D44 that Mike has in the shop and used it to position the springs and measure for hanger placement.
The front spring hanger is a standard CJ style. The rear is a special design that Mike has been using on his Jeep for a while with great success. Instead of welding the shackle eye to the bottom of the frame he put it on top. The shackle is almost a foot long and swings on either side of the frame rail - very flexy and stable.
Brad was faced with a big decision at this point - what should he do about the custom TJ Dana 44 under the rear end?
Well...it's a Currie built, reverse cut D44 with 4.10s and a Detroit. With the TJ brackets he should have no problem selling it to some lucky chap. But then he'd have to wait for a new one, and that could take waaaay too long. He debated putting a reverse cut D60 under there, but decided against it because of the timing.
Out came the torch again, and off came the TJ brackets. Some quality time with a wire wheel and a grinder cleaned up the axle so new spring perches could be welded on.
He retained use of all the brake lines. The shocks were relocated to the front of the axle using a custom hoop between the frame rails.
The last stage is testing and that's what's happening. As hoped, the Jeep is very stable on all terrain. While at TDS, Brad made it a point to get a tire in the air in the various ravines and couldn't. Well...he got a tire in the air, but not the way he was used to. This has definitely solved his tire lift problems.
He lost a little bit of flex, but still ramps well over 1000 on a 23 degree ramp. With lockers at both ends and a more stable ride it's not an issue.
Brad has a set of custom Alcan springs on the way to finish off the rear end. They're made to support all the gear he carries and maintain the 6"+ of lift.
|Finally on trail!!!|
Here's a few comments from Brad about testing the new springs at TDS 2000:
So what about the front? Brad has decided to keep the front the way it is for now. Something has to be done, but he's undecided what. Longer control arms? Leaf springs?
We'll keep you posted!