TOTM: Front suspension

[AgitatedPancake]

"Let me answer your question with a question"... should the axle-side panhard mount be on the opposite side of the axle-side attachment of the upper link in a 3 link? Or does it even matter? I have never built one personally, but if so, I suspect this is why you see upper links on the driver side in rigs with driver drop axles...

Last time I saw it brought up, I saw two seperate reasons. One, people preferred the upper link on whatever side the driveshaft is to counter the rotational torque it puts on the axle, the theory that having the link on the opposite side of the shaft might allow the driveshaft to torque/stress extra hard on that mount. The other, people generally didn't like the idea of mounting their only upper link on a single axle tube on the dana axles because of the ability to spin tubes and such. Building it over the diff involves a truss at the same time, so its a double whammy for strength.

[downtowncb]

DownTownCB, I took off a single upper off of my radus arm setup for a day to see how it felt, under HEAVY braking, the axle would pivot on the soft rubber on the axle end of the lower CA's and would cause a bit of steering slop and a pull to the right. I have heard of it being similar with a three link with any poly or rubber in the setup. I just wanted a setup that would eliminate as much movement as possible.

Alright makes sense to me. Thanks for the photos btw. Definitely something I will look into when I start building on the Jeep more in the future. Are you still using stock rubber bushing for the axle side upper joints or are they press in cartridge types?

[FortCollinsZJ]

Alright makes sense to me. Thanks for the photos btw. Definitely something I will look into when I start building on the Jeep more in the future. Are you still using stock rubber bushing for the axle side upper joints or are they press in cartridge types?

I bought a pair of those press in 2" Johnny Joints from Currie, the cast mount is the right size for the JJ to hammer in just right, but the passenger side was a bit bigger, so I welded the JJ case into the mount. Worked out great. Definitly better than the OE rubber.

[zjeepin]

Last time I saw it brought up, I saw two seperate reasons. One, people preferred the upper link on whatever side the driveshaft is to counter the rotational torque it puts on the axle, the theory that having the link on the opposite side of the shaft might allow the driveshaft to torque/stress extra hard on that mount. The other, people generally didn't like the idea of mounting their only upper link on a single axle tube on the dana axles because of the ability to spin tubes and such. Building it over the diff involves a truss at the same time, so its a double whammy for strength.

When i first built my front la's i put a single upper on the passenger side of the diff because it was easiest. It worked ok but i had a lot of axle hop like a radius arm setup and had some pinion wrap too. I believe the axle itself was flexing a little and that scared me so i made another upper, my setup is very similar to fortcollinszj except his uppers are a little closer to the floorpan than mine and i have no bend in my uppers because i have plenty of room with the 4.o...

I run a center limit too, i got my front end bound up really badly at mason jar in june and broke the passenger side one. I put a chain in on that side for gsse and ripped the tab off the axle saturday night.. without it in there i kinda felt like i was wheelin with no pants on if you know what i mean.. the rig just didn't feel right on hill climbs..

I run polyperformance limiting straps that share a motor mount bolt on the unibody end and come to a center tab on the axle. I started with the limit straps completely tight. I had to have a couple of my buddies stand on the hood when i initially installed them. over the last 3 or 4 years that the straps have been on there they have stretched about an inch so there is just a little bit of slack in there..

i bomb down the trails pretty hard too and i never noticed the suspension being limited but im still on coils and blown shocks. im sure when i upgrade to coilovers or ori's it'll be a different story.

[rstrucks]

I run a center limit too, i got my front end bound up really badly at mason jar in june and broke the passenger side one. I put a chain in on that side for gsse and ripped the tab off the axle saturday night.. without it in there i kinda felt like i was wheelin with no pants on if you know what i mean.. the rig just didn't feel right on hill climbs..

I run polyperformance limiting straps that share a motor mount bolt on the unibody end and come to a center tab on the axle. I started with the limit straps completely tight. I had to have a couple of my buddies stand on the hood when i initially installed them. over the last 3 or 4 years that the straps have been on there they have stretched about an inch so there is just a little bit of slack in there..

Trey - do you have a pic of your limit strap set up? My little brain is having a hard time visualizing it.

Anybody else have pics of theirs?

I evidently need to add a center limit to mine. I run limit straps but they are just to prevent me from overextending my shocks. They both attach to the engine mount bolts at the top.

[ATL ZJ]

this is a pic of trey's rig and you can almost see the limit straps... they run on each side of the oil pan and are taut in the pic

[DaveJeep]

I'm thinking I will try a center limiting strap on mine. Although I have not had any unloading problems but the terrain here is probably a lot different than yours, no rock crawling just trail running.

I run a radius front setup (JJs on the frame side, heim on the upper at the lower point, all rubber bushings at the axle) and 4 link rear (all JJs) with a Antrirock bar back there. I've never has a problem in the year I've owned it with the rubber bushings going bad.

[SirFuego]

I run polyperformance limiting straps that share a motor mount bolt on the unibody end and come to a center tab on the axle. I started with the limit straps completely tight. I had to have a couple of my buddies stand on the hood when i initially installed them. over the last 3 or 4 years that the straps have been on there they have stretched about an inch so there is just a little bit of slack in there..

I think I might try this. I like the idea of running two "triangulated" limit straps rather than running a single one. You figure the limit straps need to hold the entire front unsprung weight plus whatever force the compressed springs are putting on the axle. In addition, it seems like it would also act as a pivot point during articulation, so that may or may not add even more force to the straps. I'm thinking that I'll be able to drill a hole in my truss on the axle side.

EDIT: So I'm also thinking that I might be able to adjust my side limiting straps to allow for more downtravel since the center straps will in essence control the axle droop and keep the driveshaft angles in check.

When you mean the motor mount bolts on the unibody side, I assume you mean the long bolt that goes through the motor mount bushing parallel to the "Frame" rail?

[zjeepin]

I think I might try this. I like the idea of running two "triangulated" limit straps rather than running a single one. You figure the limit straps need to hold the entire front unsprung weight plus whatever force the compressed springs are putting on the axle. In addition, it seems like it would also act as a pivot point during articulation, so that may or may not add even more force to the straps. I'm thinking that I'll be able to drill a hole in my truss on the axle side.

EDIT: So I'm also thinking that I might be able to adjust my side limiting straps to allow for more downtravel since the center straps will in essence control the axle droop and keep the driveshaft angles in check.

When you mean the motor mount bolts on the unibody side, I assume you mean the long bolt that goes through the motor mount bushing parallel to the "Frame" rail?

i use the bolt that attaches the motor mount to the unibody. i thought about using the bolt that goes through the actual bushing but i thought that would put alot of leverage on the unbody as well as the engine block. Mine have been this way for probably 4 years without issue.

another benefit if the triangulated center limit strap when used with a panhard bar is that as the axle moves side to side during articulation one strap will tighten and one will loosen (depending on up or down travel) and acts like a suckdown..

i've never run any limit straps at the front tires with this setup either, my thinking is that the center strap holds the majority of the unsprung weight anyway. my theory could be flawed but it has worked well to this point and i've never broken a shock..

i highly recommend the center limit straps for those who haven't tried it.

if you don't want to spend $50 on nice limit straps just to try it out you can use chain temporarily, because it will be harsh and unless you get some heavy duty chain you'll break a link eventually

[ATL ZJ]

if you don't want to spend $50 on nice limit straps just to try it out you can use chain temporarily, because it will be harsh and unless you get some heavy duty chain you'll break a link eventually

there is also a guy on pirate selling no name limit straps for cheap. I picked up a pair of 20" quad wrapped straps for $30 shipped the other week.

[SirFuego]

Trey -- quad or double wrapped straps?

[zjeepin]

there is also a guy on pirate selling no name limit straps for cheap. I picked up a pair of 20" quad wrapped straps for $30 shipped the other week.

awesome, post up his user name or something, the replacement i bought from polyperformance is too short so i need to return it anyway..

Trey -- quad or double wrapped straps?

I was running double wrapped until i broke one on mason jar at gsse prerun.. now polyperformance only sells quad wrapped..

[SirFuego]

I'm guessing that this is it:
http://www.pirate4x4.com/forum/showthread.php?t=855647

You of course need to be a red star member at pirate to see it.

[zjeepin]

thanks jared.. i've got a request in to him already..

[ATL ZJ]

I'm guessing that this is it:
http://www.pirate4x4.com/forum/showthread.php?t=855647

You of course need to be a red star member at pirate to see it.

yeah PM this guy: http://www.pirate4x4.com/forum/member.php?u=85972

whoops too late

[zjeepin]

i hate it when that happens!

so for reference sake..

when designing a tri-4link how much triangulation is required to center the axle without constantly destroying rod ends or bushings?

I recently triangulated my rear lowers for ground clearance sake, i wasn't really looking for that to center my axle because my upper a-arm does that work but i also recently had the upper link out for some rework and noticed that the lowers weren't doing very much to centering..

im using my rear suspension as an example but im going to be triangulating my front uppers soon..

[ATL ZJ]

IIRC 40 degrees combined is about the minimum

[zjeepin]

so 20deg per arm?

so at a minimum you want 1/2" of triangulation for every 1 inch of arm length? (more or less)

i imagine at some point in triangulation you start to adversely effect your anti-squat by over triangulating because the more you triangulate you are essentially shortening the arm..

[rstrucks]

IIRC 40 degrees combined is about the minimum

Yeah that is the same number that is rolling around in my head.

[ATL ZJ]

so 20deg per arm?

not necessarily... you could tri the uppers and lowers however much you want/can fit, individually, just as long as they add to >= 40

[rstrucks]

so 20deg per arm?

I think if you have a total of 40 deg. whether it is all lowers, all uppers or uppers and lowers combined you are ok. Somebody PLEASE correct me if I am wrong.

EDIT - seconds late!

[zjeepin]

not necessarily... you could tri the uppers and lowers however much you want/can fit, individually, just as long as they add to >= 40

hmm so if all 4 arms are at 10deg the axle will center? doesn't seem like enough

[ATL ZJ]

i imagine at some point in triangulation you start to adversely effect your anti-squat by over triangulating because the more you triangulate you are essentially shortening the arm..

I highly encourage using the calculator... it is stupid simple to use and having built suspensions with and without the calculator, they definitely come out better when you use it...

just watch what added triangluation does to the rest of the susp. characteristics as you move your points around in the calc. within the constraints of the frame/ mounting locations you have to work with... I would shoot for AS in the range of 65-100% in the front, just like you would in a rear suspension.

[rstrucks]

hmm so if all 4 arms are at 10deg the axle will center? doesn't seem like enough

If you have two arms opposing each other at 20 deg. each (40 total), that would essentially be the same as having your lowers angled in at 10 deg. ea (20 total) and you uppers angled out at 10 each (20 total). Right?

Your right though - 10 degrees on each arm doesn't sound like much but when they are in opposite directions it adds up.

[SirFuego]

There was a more recent thread on Pirate regarding that and the 40 degree total angle popped up. This isn't it (I can't seem to find the right search terms), but here is an older thread on the same topic:
http://www.pirate4x4.com/forum/showt...on+total+angle