Advantages of a unibody???

[ChevyKev]

I'm sure it played at least a minor role. The jeep certainly called for more ground clearance than it's stable-mate the Eagle.

BAH-loney! the XJ already had more ground clearance due to the suspension.

Look at how nicely everything tucks up under an XJ. It's very similar to a hummer in that it's all up inside the body area. Those extra 4" can help quite a bit.

And the suspension bone is connected to the sub-frame bone... I will state again - this results in very little ground clearance in only one spot of the vehicle. You still have the sub frame sticking down in front and back. result is minimal increased clearance, and I doubt was a serious consideration from the engineers during the design phases.

My point was that they shouldn't flex at all. Flex negatively effects the suspension's ability to do it's job, side to side flex can bind steering (or rip off steering boxes), and it all ends up leading to metal fatigue (though steel is pretty good at not getting fatigued).

WHAT??? For a rock buggy, maybe - but tell me why we have rubber or polyurethane bushings between body and frame? To allow - FLEX. Over flexing may negatively effect steering, mostly this is minimal, and designed for a purpose. Some ability to flex is needed to not over-stress things, such as how suspended walkways, bridges, and sky scrapers are designed to be flexible - if rigid they would fail quicker.

As for TJ/CJ/YJ frame strengthening...That's one major benefit of tying a roll cage into the frame. It ends up bracing the heck out of it! It's like going from 4" frame rails to 5' frame rails. Big difference.

By the time you've added that cage to a fully framed rig, you've made all that steel on the underside unnecessary. Lots of buggies down south cut the frame out completely for more clearance and just integrate the roll cage (thus making a tube unibody).

We're not talking about buggies. We're talking about capable rigs and the difference between solid frames and unibodies. My point is you shouldn't NEED to add frame strengthening or a full roll cage for frame strength to have a capable off-road vehicle. Roll cages mostly are not to strengthen the frame, but protect occupants. The reasoning for hooking into the frame is to strengthen the cage in event of a roll, does it strengthen the frame? Sure. Is that most folk's purpose? Not those with solid frames.

But even on a solid framed rig that's going to see extensive off roading you generally want to put a roll cage in. As I said above, that makes the extra few hundred pounds of steel unneeded.

Again, for safety more than frame strength.

Look at a lot of old half ton pickup trucks that have been beat on. You can tell that the frame is slowly bending downward right in the middle. XJs are no different; They're fine until you beat on them. Then you need to stiffen them up a bit. The simple fact of the matter is that most of the vehicles we use in our hobby simply weren't built to handle the ever-increasing stresses we throw at them.

Compare a 1/2 ton truck with solid frame and a unibodied vehicle, abused similarly, and tell me which one suffers quicker and more. In most cases the unibody will be in much worse shape quicker. So again, on a vehicle with the Jeep name....

Did the XJ ever come with a Trail Rated badge? I thought it was discontinued before that was even started :lol:

True - but the theory was there before the badge. :pbbt:

From a safety standpoint it's probably better that you have to focus first on bracing the rig up. How many people build up big tall rigs and put the roll cage in last?

Hey - quit talking about me!