Sub frame Reinforcement ?'s

[creeperjeeperxj]

don't know if this is in the right forum but thought I should ask the Advanced people.
With full width and 37's going under the Cherokee, I’m wondering how you guys reinforce your frames? box the frame rails completely or do get away with just angle iron? Do you just do the section from the stock LCA to the rear spring hangers? Or do you box the whole frame, bumper to bumper? How thick of steel do you use? ect. any pointers and or pics would be great.
Thanks

 

[AzRick]

http://www.naxja.org/forum/showthread.php?t=903257

 

[JeepFreak21]

http://www.naxja.org/forum/showthread.php?t=17922
http://www.tntcustoms.com/webv5/xjstiffeners.asp
http://www.pirate4x4.com/forum/showthread.php?t=168280
http://www.pirate4x4.com/forum/showthread.php?s=&threadid=848&perpage=25&pagenumber=1
http://www.pirate4x4.com/forum/showthread.php?s=&threadid=61703
http://www.naxja.org/forum/showthread.php?t=903257&highlight=rails
http://www.naxja.org/forum/search.php
Billy

 

[radardog]

LOL @ the search link

 

[mattyg]

i would like to brace up the frame from the inside, i don't think it has been done before but would work,
cut acces from inside, drill mulitple hole from outside, fill frame rails with 1/8 inch rectaglular tubing, weld holes drilled from outside, weld top of tubing from inside, and yer done

matt

 

[2xtreme]

i would like to brace up the frame from the inside, i don't think it has been done before but would work,
cut acces from inside, drill mulitple hole from outside, fill frame rails with 1/8 inch rectaglular tubing, weld holes drilled from outside, weld top of tubing from inside, and yer done

matt

What is the benefit?
It seem to me that this would be more work.
It would provide less structural reinforcement (smaller box section when complete)
It would not provide any additional protection to the current rails on the trail

Michael

 

[PornstaR]

thought I should ask the Advanced people.

Yea this is where all the "Advanced" people of the world hang out :wave1:

 

[mattyg]

What is the benefit? cleaner look
It seem to me that this would be more work. Either way it is a lot of work
It would provide less structural reinforcement (smaller box section when complete) Maybe, but no one has ever done it(that i know of)
It would not provide any additional protection to the current rails on the trail Might provide some protection

Michael

idea came to me when i had to cut into the frame rail to fix a shackle bolt that had broken off
anyway one day i get around to it
matt

 

[JeepFreak21]

idea came to me when i had to cut into the frame rail to fix a shackle bolt that had broken off
anyway one day i get around to it
matt

I disagree.

It would be a lot more work from the inside out.

I don't know why exterior reinforcement could not look 'clean'.

It wouldn't help at all for things that needed to be welded to the 'frame rail'. Even sleeving and bolting things on would be difficult.

If you really don't want to plate the unibody rails, I think you're better off cutting them out all together and making a new frame.

Billy

 

[Kittrell]

I don't know why exterior reinforcement could not look 'clean'.
Billy

Agreed, whats not clean about this?

And Avery's could be cleaned up. Ground down smooth and painted.

 

[Ty2003K]

I have to agree it would be a lot of work, why not just start with a 4 runner or something. But I do believe it would be better for rigity. The box tubing inside the frame would add much more structure and resist bending better then angle welded to the outside of the frame.

 

[TNT]

do this

this

and both of these

 

[8Mud]

I have to agree it would be a lot of work, why not just start with a 4 runner or something. But I do believe it would be better for rigity. The box tubing inside the frame would add much more structure and resist bending better then angle welded to the outside of the frame.

I've thought for a long time, that with a hundred pounds of resin and chopped glass fiber I could I could make a frame that wouldn't bend or break anytime this century. Pump it full of long fiber and resin. You would have to weld on all your braces and fasteners before hand. I'd research how they build a boat keel and use the same techniques.

 

[cumorglas]

I've thought for a long time, that with a hundred pounds of resin and chopped glass fiber I could I could make a frame that wouldn't bend or break anytime this century. Pump it full of long fiber and resin. You would have to weld on all your braces and fasteners before hand. I'd research how they build a boat keel and use the same techniques.

fiberglass, kevlar and the like work best in cored composite structures and have very poor abrasion resistance compared to steel. I have built boats out of traditional wood construction, wood epoxy, cored and solid figerglass, steel, and even once back in the 90's when the bottom fell out of the market out of carbon fiber.

I don't think the frame is a very promising place to use composite technology. it might work, but i think you'd get better, cheaper results there with steel.

that having been said i do think that a set a half doors molded from cedar veneer, skinned in epoxy and 6 oz cloth are in the near future for me. and while not in the near future i definitely could see a removable hardtop of similar construction.

 

[8Mud]

I don't think the frame is a very promising place to use composite technology. it might work, but i think you'd get better, cheaper results there with steel.

I haven't researched it extensively, my first idea was to use lengths of fiber glass rope, then decided long fiber and resin would likely be just as strong. I was a little worried about the rope not absorbing enough resin.
I priced out the materials at around $650. Likely close to the same amount I'd use for steel just to do the frame. Steel is expensive here, I have some sources for resin.
The frame rails pumped full of resin wouldn't likely ding easily, would be stronger than heck. Though a piece of flat stock on the bottom may be needed for some additional tear resistance.
Sure would save a lot of cutting and welding and wondering if the finished construction was integrated or just pieces of added weight only as strong as the weakest joint.
When my 88 fails to pass it's last inspection, I'm gonna give it try.

 

[cumorglas]

I haven't researched it extensively, my first idea was to use lengths of fiber glass rope, then decided long fiber and resin would likely be just as strong. I was a little worried about the rope not absorbing enough resin.

reasonable concern. wetting that out is tough. pre pregging and baking isn't really an option a a reaonable cost.

I priced out the materials at around $650. Likely close to the same amount I'd use for steel just to do the frame. Steel is expensive here, I have some sources for resin.

650$ could buy enough steel to sleeve three xjs here. and sliders. and a pretty solid start on a cage.

The frame rails pumped full of resin wouldn't likely ding easily, would be stronger than heck. Though a piece of flat stock on the bottom may be needed for some additional tear resistance.
Sure would save a lot of cutting and welding and wondering if the finished construction was integrated or just pieces of added weight only as strong as the weakest joint.
When my 88 fails to pass it's last inspection, I'm gonna give it try.

here's my thought. i think this is probably not the best way to go. but if you are gonna anyway. ..

i'd lay a layer of 24 oz roving wet with straight epoxy. fill with chopped strand and epoxy that has been thix'd up with coloidal silica, then another layer of roving. if it's available and cheaper you could use vinylester instead of epoxy, but i would stear clear of polyester resin.

this would make them ridiculously stiff and strong and would definitely keep them from collapsing on themselves if you thru-bolted stuff onto the rails. I can't see benefit past these two things though.

 

[8Mud]

this would make them ridiculously stiff and strong and would definitely keep them from collapsing on themselves if you thru-bolted stuff onto the rails. I can't see benefit past these two things though.

When I first thought of this, it was because of the inspections here, most anything welded or bolted to the frame, will fail you. But if they don't notice? I was trying to figure out a way to significantly strengthen the frame, without it showing or being obviously noticeable. I actually contemplated opening the top of the frame and boxing the inside of it.
Not a rock crawler, but more along the lines of something Jeepspeed, that I could still leave street legal and pass inspection with.
Some way to prevent stress fractures and/or bent front frame ears. And just because I take some kind of sadistic pleasure in doing something different. Some of my creations are butt ugly, but usually work well.
I did the glass work on A.J. Foyts car for the first Ontario 500, I'm not exactly a novice. Though way out of practice and not really up to date on the new techniques and materials.
I'm now leaning towards a XJ trailer queen. And buying a TJ for my DD.
I've got a 3/4 ton Dodge frame in the driveway, a 60 dually rear axle and have done some measuring, the XJ will sit on the frame nice. But likely be to big to fit on the trailer. Big, ugly and durable.
Just thinking out loud.