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3 link Upper Wishbone Question.

2K views 12 replies 9 participants last post by  Sean 
#1 ·
I've run into a possible snag on my rear double triangulated
4 link and don't know what to do. I may end up having to use a wishbone upper with a single 1 1/4" shank by 1" bore hiem (spherical rod end, if you prefer that terminology) over the top of the rear diff to clear everything.

I've only seen a few other 3 links with an upper wishbone, but they all had the hiem over the diff positioned where the bolt went through the bore of the hiem vertically rather than horizontally.

Is this required, or can I run the hiem the traditional way with the bolt going through the hiem's bore from left to right (horizontally)?

I don't see any reason that it would HAVE to be mounted vertically......but I may admittedly be missing something.

So, what do ya think? The bracket would be much easier to make horizontal and I can't see it working any less effectively.

Thanks in advance.

Sean
 
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#3 ·
technically the right way to do it is with the bolt verticle, but many people get away with doing the bolt horizontal. The reason is that a heim is not designed to take a side-load, trying to push the ball out of the race.
 
#6 ·
How did you run into a snag when building a buggy from stratch? Build basic cage/chassis, then build suspension, then fit everything in where it will fit. I have read some of your other recent post and remember this......IT'S JUST A ROCKCRAWLER.........not rocket science. It doesn't have to be perfect. You are just going to go beat it against some rocks when done. I just winged it with alot on my buggy and it's all good. :D
As for the heim orientation, I have seen both work fine. My buddy who ran a 3/4 heim with the bolt horizontal, bent it from time to time. The heim that is.
I say stick with the 4 link. Good luck and finish that thing up.
 
#7 ·
Jack,
Building from scratch was a whole lot simpler than starting from my existing frame, BUT, if I could start over, I'd do a couple of things differently. I've learned A TON about what parameters you have to design into a buggy to make the links come out the way they should. So far, I made a couple mistakes that have caused a quite a bit of head scratching.

I think the biggest thing is: I really don't know WTF I'm doing :D or even really what I should be shooting for with link suspension.

You get so many conflicting stories around here, it's hard to tell. For example, I originally was trying to get my RC slope and angle as close to zero as possible while still remaining negative (understeer) on the RC angle. My understanding is that this would give the least rear steer.

Then I read how squirrely that will be and that I probably need more understeer (mostly for street driven rigs)........but how does that translate @ 70 mph on the dirt roads on the way to the trail? I'll never really see a paved road, but I don't wanna end up in the ditch on the way to the trail either.

Beats the heck outta me. I'm just gonna build it where it clears everything (right now, the frame is so narrow, the upper links *look* like they're gonna hit it on full droop). I won't know for sure until I cycle everything. If they hit, my only option to keep from going into oversteer, is to go to a 3 link which will give me more triangulation AND clear the frame but it also will put me at about -1.26º of understeer, whereas I'm at about -.04º now. Neither is probably a big enough difference to matter, so if it clears as a 4 link; a 4 link it'll stay. If not.....I guess I'm doing a 3 link.

Clear as mud? :) :p

Sean
 
#8 ·
stay with the 4 link. you are way overanalyzing what you read on pirate. take what you read here, and the corresponding calcs, and get a general idea of what your links should liik like, including roll axis and anti squat, then just fit shit where it fits, keeping in mind the ideas youve learned about on here. there is no perfect way to do it. remember, a buggy with -1.26 "understeer" on the trail is wayyy cooler than one with -.04 in the garage. rear steer in small amounts is not a big deal btw, and if you think it is you have read too much into this bs...."hth"
 
#9 · (Edited)
Here are the basic things I followed:
parrallel links as flat as possible.....mine are about 12 degrees, all 37'' long
triangluate as much as possible......basically I put the links where they fit
run the same vertical seperation at both ends.....mines 8''
Mine is very predictable and performs well with no rearsteer, at least I can't tell. The only climbs I haven't been able to make was due to the lack of power from the 22re. Other then that it's all good. I would rather wheel then try and create some "perfect setup", but that's just me.
 
#10 ·
A 4 link REALLY isn't very much more work than a 3 link... I was thinking about a 3 link, but a 4link looks like it might be much easier. Mine will have 50" links, 9.5" VS at axle, 5.5" at frame. Should work pretty well..
 
#11 ·
Sean said:
I've run into a possible snag on my rear double triangulated
4 link and don't know what to do. I may end up having to use a wishbone upper with a single 1 1/4" shank by 1" bore hiem (spherical rod end, if you prefer that terminology) over the top of the rear diff to clear everything.

I've only seen a few other 3 links with an upper wishbone, but they all had the hiem over the diff positioned where the bolt went through the bore of the hiem vertically rather than horizontally.

Is this required, or can I run the hiem the traditional way with the bolt going through the hiem's bore from left to right (horizontally)?

I don't see any reason that it would HAVE to be mounted vertically......but I may admittedly be missing something.

So, what do ya think? The bracket would be much easier to make horizontal and I can't see it working any less effectively.

Thanks in advance.

Sean
that somewhat how I did mine my top link looks like a half of a snowflake. sperical rod end vertical off my nine. also pivots on its own threads. which wears it out sooner. works ok, but Im changing it all this winter.
 
#12 ·
Sean said:
Jack,
Building from scratch was a whole lot simpler than starting from my existing frame, BUT, if I could start over, I'd do a couple of things differently. I've learned A TON about what parameters you have to design into a buggy to make the links come out the way they should. So far, I made a couple mistakes that have caused a quite a bit of head scratching.

I think the biggest thing is: I really don't know WTF I'm doing :D or even really what I should be shooting for with link suspension.

You get so many conflicting stories around here, it's hard to tell. For example, I originally was trying to get my RC slope and angle as close to zero as possible while still remaining negative (understeer) on the RC angle. My understanding is that this would give the least rear steer.

Then I read how squirrely that will be and that I probably need more understeer (mostly for street driven rigs)........but how does that translate @ 70 mph on the dirt roads on the way to the trail? I'll never really see a paved road, but I don't wanna end up in the ditch on the way to the trail either.

Beats the heck outta me. I'm just gonna build it where it clears everything (right now, the frame is so narrow, the upper links *look* like they're gonna hit it on full droop). I won't know for sure until I cycle everything. If they hit, my only option to keep from going into oversteer, is to go to a 3 link which will give me more triangulation AND clear the frame but it also will put me at about -1.26º of understeer, whereas I'm at about -.04º now. Neither is probably a big enough difference to matter, so if it clears as a 4 link; a 4 link it'll stay. If not.....I guess I'm doing a 3 link.

Clear as mud? :) :p

Sean
holy shit! build the 4link and forget the retarded .04*, 1.26*, .25mm and .006'', half a nanometer and a partidge in a pear tree on the trail your never gonna be on since your splitting hairs.....
 
#13 ·
Well, for any of you that give a rat's ass.......I got home tonight and cycled the links.

The upper links BARELY clear the frame, so they are staying for at least the time being.



Sean
 
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