Has anyone built a FJ40 with a 3 or 4 link front and drove it on the streets with good results? I am trying to get my plan together and have not found any examples of short arm front suspensions. I do not need much flex, but want to run 36's with about 2" of lift and some body mods. I can not have the springs hanging out in front of the tires with it that low so I want to link the front. I am looking for a guess on length of upper and lower links. Thank you all for the great info! Had the 40 for a few weeks now and used the search here ALOT.
Front 4 link for on road? (1 Viewer)
- Thread starter NE40
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RLMS
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If links are in your interst, 3-4 links on the road, is extreemly scary, with all the variabels, like evasive manuvers, I wouldn't
Radius arms however would be perfect! We have been working on radius arm kits for the cruisers, if you have any interest!!
They provide stability on and off road, good flex to boot!!
Good luck with the search
justin
Radius arms however would be perfect! We have been working on radius arm kits for the cruisers, if you have any interest!!
They provide stability on and off road, good flex to boot!!
Good luck with the search
justin
I concur, Doctors. The Ford-type (or later model Cruisers) radius arms would be the easiest and ride the best. 3, 4, and 5 link suspensions need to have the geometry figured correectly (it can be done) but its a little more work and more time consuming.
If links are in your interst, 3-4 links on the road, is extreemly scary, with all the variabels, like evasive manuvers, I wouldn't
Radius arms however would be perfect! We have been working on radius arm kits for the cruisers, if you have any interest!!
They provide stability on and off road, good flex to boot!!
Good luck with the search
justin
3, 4, or five links all behave nicely if there is a track bar involved. if triangulated linkage is used to control lateral movement (like in a conventional triangulated rear 4 link) worserness bumpsteer is introduced
If links are in your interst, 3-4 links on the road, is extreemly scary, with all the variabels, like evasive manuvers, I wouldn't
Radius arms however would be perfect! We have been working on radius arm kits for the cruisers, if you have any interest!!
They provide stability on and off road, good flex to boot!!
Good luck with the search
justin
Thre is no reason a properly designed 3 or 4 link is xtreeemmmllllyyy scary.. Panhard bar or not....
Any poorly designed link system can be scary on the street. Radius arms and panhards included.
IMHO radius arms are a huge compromise in suspension design. Any suspension that requires the joints to bind to get decent flex is a bad idea.
Keep the links rigid, and let the joints be bind free..
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I dont want to start a pissing match about 3-link vs. 4 link vs. radius, etc like the ones on Pirate but is there anything fundamentally wrong running a triangulated 4 link !\ /! on the front of or a rig that sees very little street time or is the application the same for a rig that sees a lot of street time? Any pitfalls or GENERAL guidelines trying to build a reasonable setup like this? Sifting through the crap on Pirate is pretty nauseating. I'm reading some books right now about chassis engineering but most seem more geared to the race track...
Most of the arguments concerning the reasoning not to use a triangulated 4 link on a front suspension stem from the amount of bumpsteer that can occur as a result of poor design. If at rideheight, your draglink is fairly flat, you will notice almost no bumpsteer. Same is true for a wishbone 3 link, etc etc etc..
If you design a suspension that requires a panhard bar make sure that the panhard bar has the same length and orientation as the drag link. or amazingly enough, you will have bumpsteer as well..
If lateral stability of the axle is of concern, then you have not designed enough angle into the links or you are using sloppy joints.
you might could get away with a flexy front suspension on the road if you incorperated a stability/anti-roll bar with quick disconnects for offroad use...
Dodge rams and coil sprung jeeps use a short arm 4/5 link that would be pretty easy to build. The uppers and lowers on the ram are pretty much parallel, not much caster change. The jeeps uppers are slightly triangulated and offset a bit. My XJ flexes like mad on a short arm setup. I've been thinking about doing it to the front of the 40 but coilovers are damn expensive and theres not much room for coil springs. If you don't want to do the math yourself steal a factory design. Measure link separation, angles, lengths, etc. Build to suit.
You can easily design a 3/4 link to drive well down the road. It will take some time sitting under your rig seeing what you have to work with and playing on the 3/4 link calculator. I would rather do a 3 link in the front for steering reasons and I would use coil overs with a stiffer spring rate to help with stability around corners. I would also look into the currie anti-rock sway bars to help with body sway yet still perform off road.
Also probably be in your best interest to use a bushing mount on one end of the link for a little better ride than hard mounted on both sides like a heim or johnny joint.
Also probably be in your best interest to use a bushing mount on one end of the link for a little better ride than hard mounted on both sides like a heim or johnny joint.
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What about the use of full hydro steering instead of traditional steering boxes, drag links, etc (we're negating the fact full hydro isnt street legal)? Since the steering linkage isnt attached to the frame... wouldn't that negate some of the bumpsteer effect (espeically with no panhard)?
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NE40... if I start hi-jacking your thread too much let me know. I have a tendency of doing that. I just thought some of the info I am looking for would be relevant for you too. I'm happy to start another thread if I butt in here too much.
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Bumpsteer is directly related to movement of the axle in relation to the draglink, so if you go full hydro, you can not have bumpsteer..
Johnny joints, RE joints and the like have integrated bushings in their design. It is ontly the spherical rod ends that are esentially steel on steel. But it is a good idea to have some buffer on one end of the link at least. Otherwise the suspension can transmit a lot of road "stuff". I would not hesitate to do JJ's on both ends of links..
How a truck leans into corners can be altered by suspension design as well. Sway bars are a good solution if the trucks limitations do not allow you to reduce body roll through suspension design.
LT is right, a Ton of how you design a suspension is based on where you can simpley put the links. The perfect suspension most likely will not fit under your truck. So you balance what suspension quirks you can deal with..
Johnny joints, RE joints and the like have integrated bushings in their design. It is ontly the spherical rod ends that are esentially steel on steel. But it is a good idea to have some buffer on one end of the link at least. Otherwise the suspension can transmit a lot of road "stuff". I would not hesitate to do JJ's on both ends of links..
How a truck leans into corners can be altered by suspension design as well. Sway bars are a good solution if the trucks limitations do not allow you to reduce body roll through suspension design.
LT is right, a Ton of how you design a suspension is based on where you can simpley put the links. The perfect suspension most likely will not fit under your truck. So you balance what suspension quirks you can deal with..
I would do a Low Spring over, Get some flat Springs, maybe pull a few Leafs, Shackles through the frame. Easy, Flexes good, Keeps it low, CHEEP!!
No reason to do a 3 or 4 link unless your playing hard in the rocks and have found the limit of Leafs. alot of the Home built rigs ive wheeled with work Killer with Leafs in the front and some sort of linked setup in the rear.
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Thanks Mace... I understand that fitting the "perfect" set up under my rig can't be acheived but something in the ball park is what I'm looking for. Everything with my big ugly 60 is a comprimise and if I could go back in time and start again I would... but I'm stuck with her now. 90% of the reason that I'm even thinking linking the front is that the d60 I'm getting is already trussed and set up a triangulated 4 link and full hydro steering.
I think I'll take LT's advice and sit under there and see where I can put the links and plug it into the calculator.... maybe do some more reading and see where I'm at. I'm starting to understand the concepts of anti-dive/squat, roll-center, CG, instant center, etc but is there any magically numbers to shoot for in the calculator?
With your 60... you're screwed for anything near "perfect"
Keep your uppers flat as possible with a vertical separation of 5" - 7" on the frame between the uppers and lowers. If doing a panhard make sure it runs parallel with your drag link but in your case just make it sit as flat as possible w/o any clearance issues under flex. I would run your anti squat around 80% and your COG is going to be based on how high your 60 sits in the air.
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This is what I built last year to run the river. It worked great and pulled many a j**p out, but I wanted a FJ.
So I sold the Scout and got this.
350 chevy, stock trany,tc,rear, front disc. I am putting a 4" stroke sbc in with a sm465/205/Scout dana 44's w/5.13's. Here is a pick of what we do with the rigs every weekend.
Thanks for the advice on the link front. I think I still like the short 4 link w/ panhard. I just thought someone may have done it and liked the driveabilty.
So I sold the Scout and got this.
350 chevy, stock trany,tc,rear, front disc. I am putting a 4" stroke sbc in with a sm465/205/Scout dana 44's w/5.13's. Here is a pick of what we do with the rigs every weekend.
Thanks for the advice on the link front. I think I still like the short 4 link w/ panhard. I just thought someone may have done it and liked the driveabilty.
LC_Hamma
The Anti-Leafer
I've done both types - radius arm/ y-link on the front of my 40 & haven't got my 
on the road yet, but completed a 4 link on the front of it. The 40 drives perfect w/o sway bars. Both run lifted TJ coils, F engines, stock width LC axle on the 40 & a little wider hybrid LC/ D60 outers on the Yeah, the coils are tight to the steering knuckles & the frame, but it can be done
<EDIT> click either one of the links in my sig below for pics. 4 link is on pages 16 & 17 in my buildup
on the road yet, but completed a 4 link on the front of it. The 40 drives perfect w/o sway bars. Both run lifted TJ coils, F engines, stock width LC axle on the 40 & a little wider hybrid LC/ D60 outers on the Yeah, the coils are tight to the steering knuckles & the frame, but it can be done <EDIT> click either one of the links in my sig below for pics. 4 link is on pages 16 & 17 in my
buildup
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