2004 1-ton TJ Build

[Rangerrod]

this is my latest set of numbers for my jeep. Been drawing in OnShape. Seems to work. Can't decide if I want to raise the bed of the jeep to make more room for up travel, or if I should work out a suspension system that moves the control arms lower on the axle.

I’m in the same boat. I want to keep the floor flat in mine to put a fridge on a slide. Thought about notching where the upper mounts go and just boxing it in. Interested to see what you come up with.

There’s a good idea on drenching upper mounts in to the truss in the video. You have to wade through it. But then you have to roll your lower mounts down to keep separation.

 

[67StingrayJ]

I have

I’m in the same boat. I want to keep the floor flat in mine to put a fridge on a slide. Thought about notching where the upper mounts go and just boxing it in. Interested to see what you come up with.

There’s a good idea on drenching upper mounts in to the truss in the video. You have to wade through it. But then you have to roll your lower mounts down to keep separation.

I have considered the upper mounts in the truss, or forward of. CAD is for sure helping. Numbers don't look as good when you lower the lower control arm mounts. I'm really wanting 7" of up travel and 7" down. Looks like a higher ride height may be in order. Here is my latest sketch with the upper control arm mounts one top of the truss.

 

[Rangerrod]

I’m trying to keep mine standard garage door friendly and I’ll still be in to the tub with 6” of travel.

 

[67StingrayJ]

I’m trying to keep mine standard garage door friendly and I’ll still be in to the tub with 6” of travel.

Ah... Garage door. I forgot about that. Guess when I build a shop I'll have to put in an 8' door. A man can dream.

 

[Wisconsinite]

One thing not to over look, and I ran into on my build, is there is only so much uptravel to be had with a somewhat reasonable belly height. We have the tub rails as a constraint, and can't really modify that and still use a top. Check you tire to tub rail clearance at full articulation with your desired tire size. I am thinking that with a 20" belly height, I will be 7" up 9" down and still clear the tub on 40s.

 

[FLUX]

there is only so much uptravel to be had with a somewhat reasonable belly height

Very true, often over looked.

 

[67StingrayJ]

Not sure I like this design. The uppers are really short, a lot shorter than my lowers.

What's the rule of thumb for upper and lower control arm lengths? I think I read somewhere you want the upper to be about 75% the length of the lower. So if I had a 40" lower then I'd look for around 30" uppers.

 

[Bmxbry9]

I've got an lj on trailing arms. Just the ruff stuff dual hole arms.

It's coming up on 3 years old. It's different doing technical crawling with them as they hang down lower than regular links

 

[RustyC]

What wheelbase are you running? why didd you choose trailing arms?

108 -110" not locked in yet. I chose trailing arms because if forces the use of stiffer springs and prevents the springs from bowing and hitting the shock body. and it opened up room to fit full length exhaust to the passenger rear, also moves the c/g a bit closer to the center of the rig.

 

[RustyC]

I've got an lj on trailing arms. Just the ruff stuff dual hole arms.

It's coming up on 3 years old. It's different doing technical crawling with them as they hang down lower than regular links

I looks like you raised the inner fender and allowed the top mount to be higher up? That is one thing about using a TJ/LJ tub is the rear inner fenders are not squared off like a YJ. I can't bring myself to cut my LJ tub to move mine (but was very tempted).

 

[67StingrayJ]

I've got an lj on trailing arms. Just the ruff stuff dual hole arms.

It's coming up on 3 years old. It's different doing technical crawling with them as they hang down lower than regular links

Bmxbry9
Thanks for the response.
how long are your trailing arms?
What made you decide to go with a Trailing arm vs regular links? Was it your comp cut?
How much wheel travel do you have in the rear?
What was your rig's intended use? Rocks, road, fast, show pony?

 

[gt1guy]

Not sure I like this design. The uppers are really short, a lot shorter than my lowers.

What's the rule of thumb for upper and lower control arm lengths? I think I read somewhere you want the upper to be about 75% the length of the lower. So if I had a 40" lower then I'd look for around 30" uppers.

What do those short uppers do to the pinion angles and AS through travel? Yes, 75% has been the "rule of thumb" for many years. But it IS just a suggestion.

On my pile there is only 1.375" difference between my rear uppers and lowers in side view. True length the upper is 92.4% of the lowers. I've always been a fan of running the longest links that you can fit, it makes geometry changes happen slower.

 

[Wisconsinite]

The links on the rear of my buggy are 36" C-C lower and 36.5" C-C upper.

 

[Bmxbry9]

Bmxbry9
Thanks for the response.
how long are your trailing arms?
What made you decide to go with a Trailing arm vs regular links? Was it your comp cut?
How much wheel travel do you have in the rear?
What was your rig's intended use? Rocks, road, fast, show pony?

The arms are 48" long. Most of the guys I wheel with are running them. They are nice because you gain more travel. Faster on fireroads/in the desert. The tub was originally a tj, but it's been stretched to LJ length.

Not sure on wheel travel but I've got 14" coilovers front and rear. I think I'd like to step down to a 12" to help lower it a bit. This is back when it was being built

It's meant to be an all around wheeler and fit the family. Mainly wanted a top, doors and windshield for snow wheeling. Sometimes it would be nice if it was on links for clearance on the rocks but it just gets bumped up obstacles until the tires will grab.

 

[67StingrayJ]

The arms are 48" long. Most of the guys I wheel with are running them. They are nice because you gain more travel. Faster on fireroads/in the desert. The tub was originally a tj, but it's been stretched to LJ length.

Not sure on wheel travel but I've got 14" coilovers front and rear. I think I'd like to step down to a 12" to help lower it a bit. This is back when it was being built

It's meant to be an all around wheeler and fit the family. Mainly wanted a top, doors and windshield for snow wheeling. Sometimes it would be nice if it was on links for clearance on the rocks but it just gets bumped up obstacles until the tires will grab.

Man that’s some flex! I could really use some more photos of your suspension set up. Like where the lowers connect to the frame. Like if you were to plug your numbers into the anti squat calc, what would they be? Every design I come up with in cad, the lower trailing arms hit the frame at full bump. The only think I can think to do is put the on the outside of the frame.

Also, how long are your uppers? I need details!

 

[1Sinner]

Mine is running 42 inch lower rear trailing arms 31 inch uppers to get to that 75% number. I don't have any flex shots yet, unfortunately. But everything looks good. One great thing is that I don't get a lot (4%) pinion angle change with a 75% upper link.

enjoying your build so far.

 

[67StingrayJ]

I just can’t figure out how to get my trailing arms not to hit my frame with 7” of up travel. I need dimensions and pictures of all of your setups.

 

[1Sinner]

I just can’t figure out how to get my trailing arms not to hit my frame with 7” of up travel. I need dimensions and pictures of all of your setups.

Mine is a custom built frame. If you go back through my build there's quite a few detailed pictures there.

 

[gt1guy]

I just can’t figure out how to get my trailing arms not to hit my frame with 7” of up travel. I need dimensions and pictures of all of your setups.

Are your trailing arm mounts directly under the frame?

If the arms are hitting the frame, you really only have 2 choices. Move the mounts out board or move the frame where it's hitting.

 

[Bmxbry9]

Man that’s some flex! I could really use some more photos of your suspension set up. Like where the lowers connect to the frame. Like if you were to plug your numbers into the anti squat calc, what would they be? Every design I come up with in cad, the lower trailing arms hit the frame at full bump. The only think I can think to do is put the on the outside of the frame.

Also, how long are your uppers? I need details!

I haven't put my numbers into the Calc. The trailing arms are mounted outside the frame and I have the motobilt front and rear frame half.

 

[67StingrayJ]

I haven't put my numbers into the Calc. The trailing arms are mounted outside the frame and I have the motobilt front and rear frame half.

you should plug in your numbers just to see what you got. I went from a job in Engineering, construction and manufacturing to a job in analytics. I've learned a new way of understanding things, and learned from this calc a small change can have a big impact.

Plus, if you put your numbers into the calc, you can share them with me! :)

 

[67StingrayJ]

well folks, I think I have a solid design.
112" wheel base.
40" tires
4 link trailing arm rear.
2.5" King coilover shocks with 14" of shock travel.
18.5" of rear wheel travel. (7" up, 11.5" down)
Raising the bed up 4".
10.5" of separation between Uppers and lowers on the rear diff. Good for up to 42" tires.
100%, 87%, and 75% of Anti-squat for 26", 27" and 28" upper control arm connection points.
20.5" belly height.

Ride height

Full Bump

Full Droop

Idea for storage under the floor. Thinking drawers that you can open when the gate is open. We'll see if it happens.

All on paper. Time to put it in steel.

 

[1Sinner]

There ya go!

 

[67StingrayJ]

I'm very much in the camp of built, not bought. I'm worried about my trailing arms. In CAD they're just a bent 2" tube with some plate welded to it to mount the shock. But I've been reading about anti-roll for trailing arms. I guess I want the shock to be mounted below the CL of the pivot points. Is there a rule of thumb as to how much? Obviously the lower it is below the CL the more it will be keen on getting caught on things.

 

[Bebop]

If you plan to go in the rocks this is a terrible solution IMO.
Find something else for anti-roll.

 

[06h3]

The arms are 48" long. Most of the guys I wheel with are running them. They are nice because you gain more travel. Faster on fireroads/in the desert. The tub was originally a tj, but it's been stretched to LJ length.

Not sure on wheel travel but I've got 14" coilovers front and rear. I think I'd like to step down to a 12" to help lower it a bit. This is back when it was being built

It's meant to be an all around wheeler and fit the family. Mainly wanted a top, doors and windshield for snow wheeling. Sometimes it would be nice if it was on links for clearance on the rocks but it just gets bumped up obstacles until the tires will grab.

Not to derail this thread but is that the Tom woods BAMF driveshaft? I thought they said they only want in the front with low speed applications?

 

[LScout800]

I'm very much in the camp of built, not bought. I'm worried about my trailing arms. In CAD they're just a bent 2" tube with some plate welded to it to mount the shock. But I've been reading about anti-roll for trailing arms. I guess I want the shock to be mounted below the CL of the pivot points. Is there a rule of thumb as to how much? Obviously the lower it is below the CL the more it will be keen on getting caught on things.

I did this on mine, I smack them on everything, but they just seem to hit rocks and slide up and over. I run a poly bushing at one side, and a Johnny joint at the other. My shock mounting bolt is about half an inch below the center line.

 

[1Sinner]

This is what I also did with mine. Plan to use them as skids, but obviously it's not running yet.

 

[LScout800]

Also keep in mind if you are planning on a back seat the shocks might poke up through the floor next to it, which can limit the amount of room you have for a seat. Not sure on bavk seat room in an LJ, but it is probably not a whole lot.

 

[Bmxbry9]

Not to derail this thread but is that the Tom woods BAMF driveshaft? I thought they said they only want in the front with low speed applications?

It's a HAD one, he was the local shop at the time. Was the front shaft in my old rig but has worked fine in the rear of this. I don't really drive it on the street or much at all. Looks the same as the Tom woods one