My .02 on doorless unibody Jeeps:

When I started wheeling an XJ they where still pretty fresh meat when it came to the offroad market, there was very little aftermarket support and lots of people where trying lots of stuff.  Topless, doorless and hatchelss XJs where all the rage and there was massive debate over the affect running without any, or all, of those things had on the strength of your Jeep.  As the dbate raged I took my rig and tested a few things out on the ramp at the Badlands.  On a fairly rust free 4 door XJ with no extra structure if you open the front two doors and run up the ramp they close and latch, but it takes more effort.  All 4 doors open they will not latch.  Hatch open doors closed the hatch will not shut.  Doors and hatch open none of them shut and the deformation of the body is rather noticeable at the strikers of the door.  After that I decided I was never running doorless, half doors maybe, but never doorless.

Of course this all needs to be taken with a grain of salt; I used to have a blazer with a top that was removeable to the windshield (pre '73) and you could not open both doors with the top off and hope to close them again without jacking up the center of the frame.  All vehicles, unibody or not, will twist up when used off road like that.  Just look at the bed seam on the pick up truck when it is oiff road.  vehicles are made to twist and flex to a certain degree, it's like the story of the big old oak tree and the sappling in a wind storm…

A lot of guys who hweeled XJs hard started to see cracks in the unibody at certain places and personally I think frame stiffners only make that problem worse.  You are basically stiffening one part of a structure that was designed to flex as a whole which then concnetrates the forces applied to the frame to specific areas never intended to take the whole load of the force applied to the 'frame.'   Truth be told the XJ is a disposable chassis if you plan to use it hard count on having to get a new chassis at some point becaue you are just going to tweek it, crack it or pop spot welds if it is used hard for a long time. 

Of course there are other solutions to frame flex issues…

The XJ unibody problems are NOT centered around the control arms.  Yes, there are issues with the control arm mounts and track bar mount but they are their own specific thing and have more to do with the higher angle of the arm at a given lift hieght and higher degree of twist a shorter arm experiences.  Drop brackets where one solution to this but the longer bracket put more leverage on the factory mount and actually makes things worse in the long run, in my opinion.  MJ control arm mounts are stronger but that is a whoel other issue…

Anyway, the frame flex thing…

So, here's the bit where people get all f'd up.  See the 'frame' of an XJ that everyone is out to add strength to are the 'frame rails' of the unibody structure; these are the two long channels that run the length of the jeep and look kinda like a traditional frame but are actually just open topped hat channel welded to the rest of the chassis.  These do serve as a backbone for the chassis and are a strong channel to attach suspension parts to but they are a far cry form a frame and they are only a small part of the XJ, or ZJ, or WK's actual chassis. 

A unibody is actually a form of monocoque chassis which means the the entire structure, often including doors and windows, is the chassis of the vehicle.  This means your entire rig is, in effect, it's own frame; every part of the Jeep is working with every other part of the jeep to form a structurally sound vehicle.  Forces, twist and stress are transferred all the way through the whole vehicle, it sounds crazy but the roof of your XJ is actually a important part of what makes it a solid over all vehicle.  The first hard uses XJs out there saw cracks around the B pillars, hatches and in other parts of the chassis from flexing.  Track bar, steering boxes and control arm mounts tended to bend up the 'frame' and crack as well.  There where lots of solutions out there but in every case all of these solutions just ended up moving the stress and cracking to other places on the chassis. 

I think frame stiffeners help in the short term but, in my opinion, unless you are going with a full cage you really need to look at an XJ as a disposable chassis.  Something that is just a convenient carrier for your sweet drivetrain and accessories.  Even with a stiffer 'frame' you are still using the rest of the chassis for strength and now that the 'frame'is not absorbing some of that force and is therefore transmitting that extra force to different places in different amounts then was origionally engineered you are going to see a whole new set of issues develope with the chassis.  The only real way around this in an XJ is to install a good cage tied to a frame stiffner with some mounts for the suspension tied into it as well.  But then you end up defeating the purpose of having a unibody rig…

The big upside to the XJ is that they are pretty light and compactly packaged, this is a design feature of a unibody vehicle and what makes them one of the best wheeling chassis out there in my opinion.  They are light, cheap, and very capable vehicles and the trade off you get for this is a chassis that while very strong for it's weight is not up to the task of handling years of abuse.  If you put the time, effort and materials into making a chassis that can do so you have just negated two of the three things that make it a great rig; affordability and low weight.

Long story short: If you want a Jeep, or any 4x4 for that matter, with a frame go out and buy one.  If you spend your time and money trying to make a unibody into a full frame rig you are just going to end up spending a lot of money to end up with something that is not quite as good as a full frame rig.

Mind you I love the XJ (and ZJ) and look forward to someday building another one, they are a great platform but I believe you need to accept what you have.

Moparboy said:

Sorry to hear that you wouldnt order anything from JCR but I like what they make and its at a good price. I also enjoy the fact that they were nice enough to give us a discount. But like what I always say, some people may not like something or a certain company and it may not work for them but other may like those products and it may work for them so they use those companies.

Like how a lot of people dont like Rusty's stuff but a lot of people in our club use Rusty's and never have had a problem with them or their products. I will always be a customer of Rusty's Offroad.

Evans :)

No, their stuff is nice and so are the people but when a company does the whole evangelical thing they have pretty much lost me as a customer for life; business is no place for your religion.

Rusty's is a great, a friend just put a Rusty's lift on his XJ and the quality is just as good, if not better, then his stuff was 5 years ago.  A large part of his problems came fro people wanting to have their cake and eat it too; soft springs sag, it is a fact of life…  I actually had a chance to wheel with him years ago and he is just about the nicest guy you could ever meet.

Moparboy said:

Well the whole evangelical thing doesnt bother but if you really want to talk about companies that do that, look at Skyjacker, they promote it not only on their website but in stickers as well. I dont see why a companies religious beliefs would sway anyone from buying something from them, I personally just see that as a weak cop out but thats just me, everyone has a right to their own opinion.

Evans :)

Won't buy from Skyjacker either actually.

It is not their beliefs I have an issue with; it is the fact that they are pushing a religious agenda which I think has no place in the business world. 

It's just a personal thing for me but I have always wondered about people who think it is a good idea to put religious stuff on your business website or literature, you know it has to offend someone. I did notice that JCR no longer makes mention of the Jesus Christ Rocks thing or has anything religious on their site…