Home design 3 link system

[UKlandyandy]

Hi,

I'm building my own 3 link as ee don't have any suppliers for multilink systems like you guys do. So, I'm designing all the components myself apart from the radius arms & centre link.

Another option is to use crawler rod ends (see these http://www.rockkrawler.com/pages/wjcomponents.html ) on and a solid link bar, combined they'd give 60 degrees of axle twist.

Do you think that this would be OK and would they be strong enough for the job ?

Cheers for the help,

Andy

[redrover]

47.5cm mate plus or minus for diff angle

[UKlandyandy]

Thanks for that Red, could I trouble you for a few more measurements please. What are the following dimensions :

1. Inside width of mounting bracket on X-member where the 3rd link fits in
2. As 1 but on the axle bar (if not the same)
3. Length of outside radius arms from the centre of the axle end bolt to the face of the large washer on the chassis end
4. Diameter of the radius arms

How do you adjust the 3rd link to change the castor angle ?

Cheers,
Andy

[TDI Guy]

you change the angle by the 3rd link which JP told you is 47.5cm long. It is actually threaded so you can screw it in or out to adjust the angle of your driveline.

[UKlandyandy]

Hi Randy,

Thanks for that. Think I really need to get hold of one now to complete the mounting bracket design. Picking up from other threads, do the systems affect roll as much as people suggest, do I need to be looking at fitting an anti-roll (sway) bar at the front ?

If anyone could help with forwarding a package to the UK, I'd be willing to do the same for parts sourced here.

Cheers,
Andy

[mudrover]

Just curious, but if you are going to be building this mainly from stratch, why not ditch SGs design and come up with your own 3 link? Fab up a track bar with some heim joints and some simple radius arms and you should be able to out travel a 14" shock with no trouble.

[UKlandyandy]

Hi Peter & all,

The reason I'm working on this design is that I know it will basically work. There isn't any one here with a truck that's already got a system installed, so I need to be quite confident that whatever I build will perform first time. The additional articulation I'm looking for is to match the rear setup I already have and I don't do any rock crawling here either.... cause there ain't no trails to go on. Most of my time off road will be in mud up to the bottom of the doors and over heavily rutted ground or through peat bogs in Wales.

I have been looking at the 'Johnny Joints' on the Currie website for the 3rd link. The 2" uses a 7/16" bolt and the 2.5" uses 9/16" bolt, both have studs welded on so I can use a solid bar for the link. Would I be better using the 2" or 2.5" ? If I fit one end with a JJ and the other with a PU bush (to damp vibration), will the 30 degs of movement in the JJ be enough ?

Thanks for the help,
Andy

[mudrover]

I would do a simple radius arm design as pictured (of course work out the angles) and a track rod, but I can understand wanting something that someone else has done. Yes, 30* of movement, is enough, so just run a polybush on the axle end. Also check out http://www.polyperformance.com/shop/home.php?cat=25 for lots of heims, jjs and other stuff.

If you want to get tricky download this 4 link calculator and come up with a good setup http://home.earthlink.net/~triaged/...ulatorV2.0a.zip.

[UKlandyandy]

Hi,

The link to the calculator doesn't seem to work, do you have another ?

As I already have QT Services 3 degree castor corrected front radius arms (for 2" lift). I don't really need to make the 3rd link adjustable as I can measure all the bolt position dimensions in situ before I remove the radius arms. So weld on joints can be used to increase the strength of the 3rd link.

Looking at the Currie site, does the 2"... 2.5" etc refer to the outside diameter of the JJ ?

Cheers,
Andy

[mudrover]

Sorry try this link http://home.earthlink.net/~triaged/Files/4LinkCalculatorV2.0b.zip

[Buckon37s]

I am a little confused. I def see why someone would want a 3 link but if you have no rocks, what is the point? The travel does nothing for you in mud.

[troutrover]

I took pictures and measurements of my 3 link while it was out of my D90 for a guy in the UK (Jamie Austin). He was building his own and wanted to copy it. I can send you the pictures on Monday as they are at my office. I think I have Jamie email also.

Christian

[UKlandyandy]

I am a little confused. I def see why someone would want a 3 link but if you have no rocks, what is the point? The travel does nothing for you in mud.Hi, I agree but I'm looking to balance the axle articulation front/rear. Apart from that, the trucks a toy and you've got to have all the accessories for it.... thats what there for !!!

Peter, got the calculator, thanx.

Could someone please confirm how the JJ's are measured, is the 2" it's width overall or diameter ?

Cheers,
Andy

[mudrover]

It refers to it's overall width.

[pendy]

You can not use your castor corrected radius arms with a three link. Maybe you need to see some pictures of a three link to understand how it works. The two outer links need to be mounted high to keep the axle from foldiing under like they did at the Twist off during their initial testing. And the center link has to be adjusteable to finetune the setup. Do some more homework. If you can not get pictures I will try to take some this weekend.

JP

[mudrover]

Oh no Pendy? As you can see it the picture an arm like I showed can be used in conjunction with another link and a track rod to control axle wrap and any sort of axle steer. But again like I said, you would have to figure out the exact angles to use, but it is a very basic proven 3 link configuration. So did I miss something? Please school me then, as oppossed to just saying I'm wrong...

[UKlandyandy]

You can not use your castor corrected radius arms with a three link.
JPHi Jim,

I wasn't suggesting that I did, only that, since I already have 3 degree arms fitted to correct for my 2" lift, an adjustable 3rd link would not be required. I can measure all the critical dimensions off the existing setup and transfer to the new.

Cheers,

[WhiteD90]

Oh no Pendy? As you can see it the picture an arm like I showed can be used in conjunction with another link and a track rod to control axle wrap and any sort of axle steer. But again like I said, you would have to figure out the exact angles to use, but it is a very basic proven 3 link configuration. So did I miss something? Please school me then, as oppossed to just saying I'm wrong...

This is what the guys who used the hinged/pinned radius arms were after, which was a concept that came from the Bronco crowd. It had mixed reviews on a rover and clearly didn't add significant travel. So you don't get any axle wrap, seems like it would want pull if you jumped on the brakes hard, no?

Tis

[mudrover]

Yes your right it is the same thing as a hinged radius arm. Tis, do you know of any threads that covered a hinged radius arm on a Rover? I ran one on my other bronco before selling it and it worked flawlessly on road while pinned, but still flexed like a slinky on the trails. As far as performance under hard braking, yes it does look like it would tend to want to shift a little, because it would be acting like an unpinned radius arm. However it doesn't seem to cause that much in the pictures or in cad renderings that i've tried to the point where the suspension is not a viable option. Am I missing something? There is no one single perfect suspension design. The suspension is sceeps on pirate4x4 for his dads bronco. I'm sure if you PMd him he could give you some real world answers. To me it would be perfect for the front of a land rover where you can't fit a triangulated 4 link. I plan on using this design on the front of my sisters disco once it gets retired from daily driver usage. So give me a year and I'll have a real world answer on how it works on a rover.

[TwisteD90]

Before I bought my SG 3-link I had this in mind. Reuse the stock radios arms however, you need to cut off the front end of it, where it bolts to the front of the axle, so it only bolts on the behind the axle. All you need is a third link, which is easy, but before that you either get HD cross member or reinforce the stock unit somehow. On the axle above the third member you build a bracket and then attach the third link from there to the Xmember. So basically the outer links are below the third link. This should give you enough separation and not cause the axle to wrap. Never done it but I though it’s a cool idea with less $$.

[mudrover]

Yousef, I like the idea of your poor mans 3 link. The only obstical would be if there is enough room on full compression to not hit anything.

UKlandyandy did some searching and came up with some pics of RockRover's 60 swap (which uses a home brewed SG setup) to maybe give an idea on how to do yours.

[pendy]

Oh no Pendy? As you can see it the picture an arm like I showed can be used in conjunction with another link and a track rod to control axle wrap and any sort of axle steer. But again like I said, you would have to figure out the exact angles to use, but it is a very basic proven 3 link configuration. So did I miss something? Please school me then, as oppossed to just saying I'm wrong...


Your wrong. If you want to pay tuition you can come to camp.

I see no third link in your pictures. If you were talking about a different type suspension I did not pay attention. I just noticed the threads lead person talking about his castor arms and the three link. If you have another idea you are presenting then get on with it. No need to puff your chest out for me.

As far as measureing his connection points and building the three link from his current positions, that seems good in theory. But most every custom suspension design has adjustable links. And I think he is limiting his work not to add the adjustment.

Twisted are you worried about the oil pan on you low budget approach?

JP
Chaos follows me, so get in line.

[TwisteD90]

Ok this was an idea three years ago but might give it a try after I talk to Keith. Now I just went to the garage and looked at both 90's, SG 3-link and one with radius arms. I noticed there is no way I can run the 3rd link on the top of the pumpkin since there is a drive shaft. However, offsetting the 3rd link to the left will clear but less separation the lower and upper links, no problem I'm sure there is something can be done (higher bracket maybe). Another problem I noticed is I'm running double CV DS so this could be another clearance problem where the other D90 was running stock DS and has ton's of room. Oil pan? It may clear depending on how much up travel you have and what size bump stops you are running. Maybe I can convince Keith to build one under the Disco, but it will be hard to sell the kid as a mail order unit since it won't be a bolt on like the SG unit.

And what’s with the “poor man” and “low budget”? Are you guys saying I am a cheap person? :)

[WhiteD90]

Mudrover-

I think the hinged debate may be in the archives of the d90 yahoo list. Quinn Dusenberry was a bronco/D90 guy who made several arms for others. A number of people claimed to get travel similar to that of a 3 link, it didn't appear that way to me in the photos. Not to mention most were not running the front shocks outside of the springs; what I can confirm firsthand is that even with a 3 link and not relocating the front shocks, travel is still relatively limited.

If you want a four link take a look at Greg Jevne's buggy. It is built on a defender platform, although I don't remember if he tubed the whole chassis or just the rear portion. He runs a four link using 4 of his heim jointed rear trailing arms and it seems to work well. When we were at the Chili Challenge two years ago it was hard to pinpoint a difference in performance of Dougs 3 link setup vs Gregs 4 link.

Yousef-

Ed Magoffin's(now Hanz') D90 had an early SG 3 link which Matt reworked and ended up welding the center link to the top side of the diff. Dont know if it is still like that or not. David B seems to have a system using the stock links that works pretty well...from pictures anyway.

Tis

[mudrover]

Pendy,
My mistake I thought you refered to my arms as caster corrected arms when you where talking to UKLandy. I will make sure to have some caffeine before I post next time. And yes he should use heims/JJs with atleast one threaded end to adjust his link length. How much does tuition cost so I can learn to play with the big boys?

Tis,
I know of Quinn from the EB world which was years ago. Is Greg's buggy the one I posted above (RockRover)? I found some pics of wristed D90s and I'm with you, not impressed. This is surprising because the Fords benefit from the wristed arm alot. Like you mentioned the shock mounting is probably the limiting factor.

Now does anyone want to guinnie pig a wristed axle housing??? http://www.bcbroncos.com/frontsusp1.html

[WhiteD90]

No, Doug is Rockrover. Greg owns Safarigard, he has a builup photo album on his site www.safarigard.com





Pendy,
My mistake I thought you refered to my arms as caster corrected arms when you where talking to UKLandy. I will make sure to have some caffeine before I post next time. And yes he should use heims/JJs with atleast one threaded end to adjust his link length. How much does tuition cost so I can learn to play with the big boys?

Tis,
I know of Quinn from the EB world which was years ago. Is Greg's buggy the one I posted above (RockRover)? I found some pics of wristed D90s and I'm with you, not impressed. This is surprising because the Fords benefit from the wristed arm alot. Like you mentioned the shock mounting is probably the limiting factor.

Now does anyone want to guinnie pig a wristed axle housing??? http://www.bcbroncos.com/frontsusp1.html

[UKlandyandy]

Hi guys,

Thanks for all the help, I've now got my basic system sorted with regards to components etc. I've spoken to the guys at QT Services and they'll make me some bespoke versions of there ultra light arms with a single bush on the front end for the axle (http://www.qtservices.co.uk/newprod.htm). Christian pointed me in the direction of agri suppliers for an adjustable tractor link for the 3rd link, this will give me the adjustability for castor correction. Just need to find one with the correct hole centres etc.

So, will get the rest of the metalwork drawn up now ready for fabrication over the next few weeks.

Cheers,

PS, pic of photo composite of QT arm and tractor link ( at the bottom and it'll need jam nuts... I know)

[Buckon37s]

Why don't you guys do this. Simple, better than a 3link and rides wonderfully on and off road. And no, you don't need a sway bar. When I took these pictures there was still 3.5in of uptravel on the compressed side that was not used because I need to adjust the spring stop on the coilover.

[mudrover]

Uklandy, I can't say that I recommend using a tractor heim joint. Most are not capable of sustaining the radial loads needed in an offroad suspension, and also they tend to wear out and become sloppy. Do it once and do it right with atleast some quality heim/JJ on one end and either a bushing/heim/JJ on the other. You can buy weld in inserts for them and weld them onto the apropriate walled tube.

Buck very interesting, is the frame mount side stock?

[Buckon37s]

Man, that 37in looks tiny there, I just noticed. Yes, one arm is completely stock and both the frame mounts are bone stock. It lacks bling but it takes 2 hours fab time to do the whole thing. I have attached a pic of all the room left in the coilover so there is still a lot of travel, I just haven't had time to snap another picture after adjusting the coilover.

[Kev Baldwin]

There isn't any one here with a truck that's already got a system installed, so I need to be quite confident that whatever I build will perform first time.

On the contrary. There are a number of 3-links in use in the UK. A guy on the UK Winch Challenge scene called Bryn Hemming was making his own up a couple of years ago. I'm sure you'd be able to track him down through one of the UK forums. I know of a few SG systems in use too.

Specialist Leisure are now importing SG stuff into the UK. They're quoting £700 for the 3-link which doesn't seem too bad when you compare it with the £1000 they want for the SG front bumper-steering guard extra!

Kev B

[mattwhite]

Buck,

It lacks bling but it takes 2 hours fab time to do the whole thing.

Nice setup, but I think you're forgetting to add in the cost of coilovers and the time and money it takes to fab the mounts for them also. :finger

Matt

[Buckon37s]

I ain't forgetting nothing. Who says you need coilovers. You can run it with poor-folk springs too. :sneaky

[Mike Hippert]

You know I was looking at that today, the spring pad is right in the way of the where you would place the arm. Is there a reson the arm has to be on top of the axle other then clearance? And I don't know that the local welder can fab up that other fancy arm you have there, I can't see that modifing the mount would take very much time.

[Buckon37s]

The arm is mounted on top of the axle for no other reason than it helps with the clearance. You can run it below. The mount is very simple but the arm is simple too. Any decent fab guy could do it. It is cast so there is a small amount that goes into welding, but not much. Simple and cheap, now I have to get back to solving my intercooler crisis!

[Mike Hippert]

Sweeet! Thanks man!

[mikeslandrover]

Hi Peter & all,

The reason I'm working on a design that's similar to the SG system is that I know it will basically work. There isn't any one here with a truck that's already got a system installed, so I need to be quite confident that whatever I build will perform first time. The additional articulation I'm looking for is to match the rear setup I already have and I don't do any rock crawling here either.... cause there ain't no trails to go on. Most of my time off road will be in mud up to the bottom of the doors and over heavily rutted ground or through peat bogs in Wales.


Just noticed this thread. There are 3 link systems in this country :cool:
Home grown ones :cool:
Based on SG. You need to get along to some of the winch challenge events or have a look at some back ssues of LRM.
A hybrid LR known as The Black Pig Built by Paul Whiteman runs a 3 link system and has around 40" of wheel travel between diagonally opposite wheels. It's rather good off road. keeping all the wheels on the ground helps even if there isn't much in the way of rocks. Check out the LRE forum and Horsham and district 4x4 club web site

Nice disco bumper Kev, saw the LRM feature on it. D'OH thread hijacking :eek:

[UKlandyandy]

There are 3 link systems in this country :cool: Home grown ones :cool: Based on SG.I'm working on a total budget of £500ish, and that includes some new shock's too.

Anyway, heres a pic of my progress to date, showing the all the front axle components mocked up in cardboard on the axle casing. There all drawn up on AutoCAD and I'm waiting for a quote from the local laser cutters. Just the cross member to finish off now.

Cheers,
Andy

[TDI Guy]

Andy, that looks good. IT appears that you are a master with the cardboard. I bet that setup will have some great results

[UKlandyandy]

Andy, that looks good. IT appears that you are a master with the cardboard. I bet that setup will have some great resultsThanx, cardboard... AutoCAD & spray mount adhesive.... the engineers best friends...
Wish it was as easy to cut 8mm thick steel plate...... with scissors.... LOL

[Buckon37s]

"3 link system and has around 40" of wheel travel"
:lol :lol :rofl :rofl :stick

Man, thanks for the laugh

[UKlandyandy]

"3 link system and has around 40" of wheel travel"
:lol :lol :rofl :rofl :stick

Man, thanks for the laughAnd your point is ????

Thought about it..... and considered, to mount the hockey sticks above the axle you need to cut & weld new brackets on.

My 3 link you bolt on..... I get the cost down to say, under 500 quid.... I sell them as a kit.... no welding, you cut you existing radius arms down & use them... I make a few quid in the process.....

Now who's laughing..... me, all the way to the bank !!!!

[Buckon37s]

Man if you don't get it, I can't help you. Now what is a quid, is that a pound? Euro??

btw: my suspension has 821.52 inches of wheel travel, and a toaster.

[UKlandyandy]

Man if you don't get it, I can't help you. Now what is a quid, is that a pound? Euro??

btw: my suspension has 821.52 inches of wheel travel, and a toaster.It's a £.... and I have pity on your toaster.... LOL

Ok, sensible now... explain why putting the radius arms over the axle increases travel. Is it not the same as being under it ? in that the twisting forces applied to the bushes on the axle limit travel, be it mounted above or below.

[Mike Hippert]

Ok, sensible now... explain why putting the radius arms over the axle increases travel. Is it not the same as being under it ? in that the twisting forces applied to the bushes on the axle limit travel, be it mounted above or below.
I think you missed this, I asked the same question.

The arm is mounted on top of the axle for no other reason than it helps with the clearance. You can run it below. The mount is very simple but the arm is simple too. Any decent fab guy could do it. It is cast so there is a small amount that goes into welding, but not much. Simple and cheap, now I have to get back to solving my intercooler crisis!

[UKlandyandy]

I think you missed this, I asked the same question.Hi Mike,

Saw that, but does it still not bind up on full travel ? or am I missing something here....

[redrover]

Andy does the tie rod clear the forward inside surface of your boxed steel tube on full steering choc? Looks good. The reason I say this is my SG is a rectangular box. I have never looked underneath to see how the tie rod travels when going from full lf to full right. But i have noticed a rub area. jp

[Buckon37s]

"Saw that, but does it still not bind up on full travel ? or am I missing something here...."

I get it. Your missing the modified radius arm and mounting. Thats what is unique, not mounting it over the axle.

[UKlandyandy]

"Saw that, but does it still not bind up on full travel ? or am I missing something here...."

I get it. Your missing the modified radius arm and mounting. Thats what is unique, not mounting it over the axle.
Right... thought I was loosing it.... totally, what did you do to the arm & mounting ?

[mudrover]

Right... thought I was loosing it.... totally, what did you do to the arm & mounting ?

What David did besides flipping the arm on top of the axle for clearence was to cut off the second (farthest out) bushing mount on the radius arm. Then he shortened the distance between the two bushing mounts and welded them up, and made a new bracket on the axle. This relieves a lot the binding issues with the suspension, and I'm assuming it causes little to no change in driveability (braking, axle steer). Just look at the pics he posted and compare the two arms.

This should be something cheap and easy to do. However, you couldn't get the clearance he got by mounting them on top of the axle, because the spring perches would be in the way.

Mike, about welding the arm. Yes it is easy to do, since the arm is cast you need to preheat the arm before you weld it up. Any decent fab shop can do this. Also it wouldn't hurt to plate it on both sides after you weld it up.

[Mike Hippert]

Cool, there is a local welder who does everything! He should be able to do this.

[UKlandyandy]

I see (now).... didn't notice that.... Doh !!! just call me Homer..... makes perfect sense. Good idea and using the origional arms saves cost too. My only concern would be that all the stress is concentrated into the welded area and I agree that this should be plated both sides with say, 1/4" thick material to prevent a major failure.

I'll still persue the 3 link as I've already ordered the laser cut parts and I don't want to butcher my existing axle at this time, however, I can always try your way if it doesn't work out like I want it to. If people wanted to modify there axles in this way I'm sure QT Services would make some bespoke arms based on there ultra light ones if you didn't feel happy modifying the origional cast items.

Have attached a couple of pics of the radius arm plates that I've drawn up and will post some pics of the completed parts once I get them fabricated.

Thanks for the help so far.....

[UKlandyandy]

Hi,

Just to get things straight in my own mind. The more lift you have on your rig, the longer the third link needs to be to correct the castor angle.

Correct ?

Cheers,
Andy

[mudrover]

Yes, the more you lift your truck up, the worse your castor, but don't forget you have to take into account pinion angle aswell.

[redrover]

Yep, you would need to extend center link to keep the u joint angle the same at each end and caster sim to stock. OR you could angle the pinion up and use a double cardan drive shaft. But this will deff screw the caster. JP

[UKlandyandy]

Thanks guys.

Was just making sure I'd got it straight in my head. I can sort the 3rd link now and make it adjustable by having the mounting on the x-member seperate and bolt on (heavy duty) thus allowing it to be shimmed to set the castor. Means I can use another modified radius arm to keep the costs down.

Will use a high yolk angle prop for the front with double cardon as well.

Cheers,

[UKlandyandy]

Hi Guys,


Have got the laser cut parts and tacked them all up now. Here are a couple of pics of the progress.

Cheers,
Andy

[UKlandyandy]

Latest pics.

Axle tube and x-member all completed. I'm just waiting for the new radius arms & 3rd link from dave at QT Services. They should be here very early in the new year.

Cheers,
Andy

[troutrover]

Andy, looks good! What did you decide to use for your center link?

CB

[UKlandyandy]

Andy, looks good! What did you decide to use for your center link?

CB

Hi,

I'm goign to use a shortened version of the outer radius arms. This will allow me to use off the shelf poly bushes and it keeps the design simple and easy to service in the field. I'm fairly confident that I won't suffer significant changes in castor due to the bushes compressing as when there tightened up there heavily compressed already.

Cheers,
Andy

[Buckon37s]

Remember that on the Center link there is 6 times more force applied to that arm than a standard radius arm sees.

[TDI Guy]

I agree with David, I bet you will have to change that link. With all that force I think the bushing will wear and you will get alot of play very quickly and the fron end will be knocking back and forth and making it very sketchy at the wheel.
Other then that, It looks great.

[UKlandyandy]

Will see how it goes, if I need to then it's not a big job to fabricate a new x-member mounting and get a link made up. Will prob go for one with rose joint ends if I do have to. At the end of the day it's all good fun and what I like about Landy's. There big toys to be messed with.....

Cheers,
Andy

[Buckon37s]

Will see how it goes, if I need to then it's not a big job to fabricate a new x-member mounting and get a link made up. Will prob go for one with rose joint ends if I do have to. At the end of the day it's all good fun and what I like about Landy's. There big toys to be messed with.....

Cheers,
Andy

Thats all fine and good but when these things go it's not like a broken half shaft. It breaks, your front end moves, your truck follows. I would think hard about building it right the first time.

[ezzzzzzz]

I'm building a 3 link too. I find it sadly humorous that the basic question asked by Andy was never answered. Everyone wants to put in thier two cents worth and the subject goes off on some awkward tangent. My center link is being built using poly bush 1" rod ends (3/4" bolt hole) and 2" DOM .25" wall tubing. That should be sufficent for any loads placed on it including a head-on collision. The drawings of the brackets were the very tihng I've been looking for. Thanks, Andy!!!

[Buckon37s]

congrats