Advantages of a unibody???

[Advent]

More ground clearance? :tease:4 inch gain for 3.5 feet maybe. Did Jeep really engineer this vehicle to be a unibody for ground clearance reasons? This to me sounds ludicrous. Why would they need ground clearance? Speed bumps in shopping malls? These vehicles can be built into incredible wheeling rigs, but they were not designed that way from the factory. Thus it is incredibly highly unlikely that ground clearance played into their decision making.

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.

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.

This argument makes no sense - while yes, the frame twists some, the body is designed to flex with the frame. So you don't have the same issues as a unibody vehicle where the frame isn't as supportive and the body twists more. You're comparing apples and thermostats here. Most solid framed trucks that are made into serious wheelers take little to no strengthening (except around the chevy steering box:doh: ) because the body flexes with the frame. [and I have flexed my plow truck before, thank you!]

Also, how many TJ/CJ/YJ's need frame strengthening when making it a more capable rig? We aren't talking about a vehicle the length of a pickup - we are talking about an XJ.

My point wasn't that the body and frame should flex together. 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).

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).

My question was Jeep specific - Jeep being somewhat synonymous with off-roading. So why put a unibody under a vehicle with the off road name, that when you make it into a more serious off-roading vehicle you HAVE to do the work yourself to make it as strong as a solid framed vehicle from the factory?

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.

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.

What's the problem? all the extra work to get a similar result in a vehicle that is supposed to be trail rated in the first place.

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

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?