Can I get a visual aid on what "5 link" means?

[atomicjoe23]

Of course it would move. . .it would be limited, but it would still move. . .it would still have the movement allowed by the heims themselves. . .assuming that they aren't triangulated which if you are running a 5-link shouldn't be necessary anyway. . .if you are running triangulated lateral suspension membersthen you are limiting the suspensions ability to move (articulate) just as much as if you had plated the arms together. . .in fact a plated parallell arm set-up would have more articulation than a non-plated, triangulated set-up. . .

. . .a five link is pretty much like a non-triangulated 4-link with extra panhard bars to locate the axles side-to-side, the idea being to limit movement, if you properly design the set-up so that it arcs correctly your axial suspension links will allow the rear wheel to move up and back as it encounters an obstacle in it's path. . .just like doing a shackle reversal for a leaf spring. . .switch from a front shackle to a rear shackle and the tire will be able to cycle up and back over the obstacle instead of the up and forward.

. . .how much movement fore & aft do you want your rearend to have? If you're running a 5-link your axial links aren't going to all a ton of fore & aft movement anyway., only what is allowed by the tire/wheel moving along the arc of the axial suspension links. . .they are your limiting factor here not the lateral links.

My last buggy used a single semi-trailing arm set-up pretty much exactly like a baja bug or a class 1, etc. that didn't allow a ton of movement either and it's only a single suspension member. . .I'm going to be building a 5-link or 3-link for my next buggy, I'm finishing up the front end now and I'll be moving onto the rear next week.

[atomicjoe23]

Meant to ask earlier. . .seems like most of you guys are mounting your shocks on the top axial link. . .why is that?

I have always been taught that your lower shock mount should be below the centerline of the rod ends axis (assuming you are using rod ends on both ends and not a bushing on one end or both). . .if you mount above the centerline you are putting unnecessary stress on the shock, shock mounts, the suspension link, and the rod ends. If you are mounted above the axis of rotation everytime the suspension compresses the mounting arrangement will force the shock to try to flip/twist the suspension link around so that the pivot point is below the axis of rotation.

The best way I can think to describe it is like standing up in a canoe. . .if you stand up on the bottom of the canoe you are much more stable than if you try to stand up on one of the seats (go ahead and try that one out for yourself. . .I dare you!). . .this is why you see trailing arms with recessed shock mounting points or if they are made out of a single tube the tube is usually bent and the shock is mounted below the centerline of the axis of rotation.

So yeah. . .why running an upper and lower link when you already have upper and lower lateral links to help in locating the driveaxles?

and why mount to the upper link. . .pretty much the opposite of what you usually see?

[minibajaman]

I have designed and built 2 buggies with 5 link rears so I know how they work. One is my personal buggy.

Originally Posted by atomicjoe23

If you want a strong 5-link (or 3-link using two members going from the chassis to the wheel laterally and a single member going from the chassis to the wheel axially. . .like a trailing arm) all you have to do is add some plate to the bottom of the two lateral members. . .if you wanted it to look like you had built some boxed lower arms plate the top and the bottom.

So are you saying here to plate each link individually, or use plate to connect two links together?

Originally Posted by atomicjoe23

Of course it would move. . .it would be limited, but it would still move. . .it would still have the movement allowed by the heims themselves. . .assuming that they aren't triangulated which if you are running a 5-link shouldn't be necessary anyway. . .if you are running triangulated lateral suspension membersthen you are limiting the suspensions ability to move (articulate) just as much as if you had plated the arms together. . .in fact a plated parallell arm set-up would have more articulation than a non-plated, triangulated set-up.

So if in your above statement you are saying connect two links together with plating, then no the suspension will not be able to move. A 5 link is basically 3 parallelograms arranged in some fashion. The corners of each parallelogram are the pivot points. Adding any rigid member in the middle of any parallelogram will no longer allow it to pivot. Rod ends alone will not allow motion.

Originally Posted by atomicjoe23

Meant to ask earlier. . .seems like most of you guys are mounting your shocks on the top axial link. . .why is that?

Most of us? I have never come across a setup where the shock lower mount was above the top axial link centerline. Please show me one.

Originally Posted by atomicjoe23

I have always been taught that your lower shock mount should be below the centerline of the rod ends axis (assuming you are using rod ends on both ends and not a bushing on one end or both). . .if you mount above the centerline you are putting unnecessary stress on the shock, shock mounts, the suspension link, and the rod ends. If you are mounted above the axis of rotation everytime the suspension compresses the mounting arrangement will force the shock to try to flip/twist the suspension link around so that the pivot point is below the axis of rotation.

This is why you see trailing arms with recessed shock mounting points or if they are made out of a single tube the tube is usually bent and the shock is mounted below the centerline of the axis of rotation.

This is all correct and how it is usually done. My personal buggy mounts the shock to the carrier to eliminate this issue. The second buggy I designed with a 5 link I took the bent tube approach to put the shock just below the centerline of the rod ends. I wanted the increased leverage that you get from mounting on the trailing link. See the red buggy in attached picture. The other picture is K-fabs Briggs cars, which use a straight tube with a custom end on the shock to move the pivot to the centerline.

[Bugpac]

You wont get much movement making it a 4 link, By boxing the lower links together that is exactly what you are doing, youll be lucky to have 1" of travel..

[ProtoDie]

Lots of good info posted here.

We have been using dual A arms for years, and are real happy with them.

Dual A arms are a little harder to design to the sprocket drive line with a live axle set up.

The upper forward mount on the sprocket side, needs to have the chain directed around it.
It is easier with the RPM gear box because the driven sprocket is higher and you do not have to deal with the Arm mount location.

My preferance is equal length dual a arm, because you only have to build 1 jig for all 4 rear arms.
This makes it easy to replace or build a new one if you wreck.
And it is easy to carry 1 spare that can replace any of the 4 A arms on the rear.
To do this, you need to keep your shock mount on the rear wheel carrier and not on the A arms

Mounting locations & pivot points are critical in all of these types of suspensions.
Moving a mounting point an 1/8" can increase your camber change, or your axle plunge quite a bit.

[atomicjoe23]

Minibajaman. . .thanks for the pic's. . .I didn't look at K-Fabs picture closely enough to notice the bracket that allows it to being mounted below the c/l of the pivot point.

I'm gonna have to do some motion analysis to see if what I am visualizing is incorrect. . .might take me a little while because I'm just getting into SW's, but I will make a 5-link and then I will make a plated 5-link (if you wanna call that a 4-link that's fine with me. . .I don't care) and see how much the motion is restricted and how much travel you lose.

I don't think the statement "you'll be lucky to have more than 1" of travel" is accurate. . .

[atomicjoe23]

Minibajaman. . .care to share the dimension of the links in your 5-link set-up? Just give me center of pivot point)-to-(center of pivot point) of each of the links and make sure you let me know the distances between them. . .if it's not to much work and you don't mind

That way I'm working with an actual functional set-up that is similar to what others on here will be running. . .and no one will be able to say I fudged mounting locations just to prove my point, proving my point is not my intention. . .I want to see what happens and what you gain or lose with each set-up and will share the results on this thread (don't be surprised if this takes 2 weeks or longer. . .I'm taking 24 credits this quarter on top of my own buggy project and my girlfriends '49 Jeep Willy's project as well. . .a LOT going on!)

. . .what's your travel limited to? bump and droop

Thanks!

[nutz4sand]

Joe take a look at the pics above Bajaman posted. Especially the second Of K-Fabs Briggs buggy cause it shows it easier being so open.

If you plated any two of those linkages together how is it gonna move more than the slop in the heims (and good heims have VERY little)

Just visualize the hub carrier going up. As it does the angles between EVERY tube in that five link is gonna alter quite a bit.

If you connected any two of them they WOULD lock it up.

If not we would not need all the $$$ hiems for a five link to allow this motion and could uses simpler cheaper bushings.

[LiveWire]

Starting with a 5 link, you can connect one of the forward links to one of the inner links if they then share one outer ball joint (eg Pilot). If you do it twice, you now have A-arms and the third inner link is the tie rod.

You can box the two lower inner links if you get rid of the forward links altogether. You now have an H-arm. The upper link can remain a single link which prevents possible bind from upper and lower arms not being parallel.

[minibajaman]

Originally Posted by atomicjoe23

I'm gonna have to do some motion analysis to see if what I am visualizing is incorrect. . .might take me a little while because I'm just getting into SW's, but I will make a 5-link and then I will make a plated 5-link (if you wanna call that a 4-link that's fine with me. . .I don't care) and see how much the motion is restricted and how much travel you lose.

Once you put it in SW you will understand my point better. The "4 link" version will not be able to move.

Originally Posted by atomicjoe23

I don't think the statement "you'll be lucky to have more than 1" of travel" is accurate. . .

That's true, it's not accurate because there will be 0 travel.

Originally Posted by atomicjoe23

Minibajaman. . .care to share the dimension of the links in your 5-link set-up? Just give me center of pivot point)-to-(center of pivot point) of each of the links and make sure you let me know the distances between them. . .if it's not to much work and you don't mind

. . .what's your travel limited to? bump and droop

I don't have the exact dimensions handy but my personal buggy is very simple. Trailing links are about 24" long, pivots about 5" apart. Toe links are about 16" long, pivots 5" apart. The upper toe link to lower toe link pivot on the frame side is 4.5" to get some camber change. Otherwise there is no funky geometry. Total travel is 13", about 4" droop travel.

Originally Posted by atomicjoe23

That way I'm working with an actual functional set-up that is similar to what others on here will be running. . .and no one will be able to say I fudged mounting locations just to prove my point, proving my point is not my intention. . .I want to see what happens and what you gain or lose with each set-up and will share the results on this thread (don't be surprised if this takes 2 weeks or longer.

It doesn't really matter because there is no possible practical configuration that will work in SW.