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Need 4-link calculator help ,

yellowK20

yellowK20

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I can't find any good links to the calculator , all of them are dead

Also , I have come to the point where I need to make some choices.

Triangulated Lower 4-link

Or

3-link with panhard

Or

"Modified" Radius arm with panhard ( basically a parallel 4-link but the top arm gets attached to the lower with heims at all points.)

Or

Parallel 4-link with panhard similar to Dodge/Jeep and Off-road designs coilovers kit.


My known components thus far:

45" tall tire
16" sway-a-ways
Full-hydro steering
SM465/203/205 (Ford or GM)
Chevy or Ford front 60
Currently have 8 , 1-3/4" by 3/4" heims with tube inserts (but can get two more. If needed)


I'm looking lots of bind free travel , soft ride and ability to take a decent hit at speed .
 
sreidmx said:
What what are you doing with the truck? And is this front or back?
Click to expand...


I'm guessing it's a front suspension... those are a lot of complicated choices for a non-steer (rear) axle.

If you are trying to fit mechanical steering into the mix, the packaging gets even MORE challenging... I really wanted to figure out a way to do a front 4-link with mechanical steering. But I eventually had to admit defeat just like every other person that tried it.

Ultimately, you build what fits under your truck. The calculator is a good way to confirm that your link mount positions are decent, but if you try to design the whole thing with the calculator FIRST, it just going to frustrate you. You wont likely be able to put links / brackets in "ideal" locations anyway...


-G
 
I need help finding a good link to the calculator so I can have a baseline for how long my links need to be , what my ideal vertical seperation should be ect .

I'm leaning towards a 3-link , with my top link being on opposite side of the front diff for clearance reason
 
yellowK20 said:
I need help finding a good link to the calculator so I can have a baseline for how long my links need to be , what my ideal vertical seperation should be ect .

I'm leaning towards a 3-link , with my top link being on opposite side of the front diff for clearance reason
Click to expand...


If you can't find one anywhere hit me up: gregblanchetteATgmaildotcom

I'll send you the .XLS directly.


-G
 
yellowK20 said:
I need help finding a good link to the calculator so I can have a baseline for how long my links need to be , what my ideal vertical seperation should be ect .

I'm leaning towards a 3-link , with my top link being on opposite side of the front diff for clearance reason
Click to expand...
If you go this route like a parallel setup minus one side link and a panhard it'll drive decent, just prepare for body roll, then tend to have a decent amount.
 
sreidmx said:
If you go this route like a parallel setup minus one side link and a panhard it'll drive decent, just prepare for body roll, then tend to have a decent amount.
Click to expand...


Bottom links will be 15 degreeish or so , that "should" help with the body roll Vs a parallel 3-link right?
 
I know the wider you go the more the stability.....So I guess every bit helps. I would guess you will find you'll need run some kind of sway bar.
 
Keep Roll Axis as high and flat as possible :waytogo:

Some other stuff people tend to use as "rules of thumb" to get into the ballpark and avoid blatant design issues:

  • Keep Upper Link Length at 70% of Lower Link Length
  • Keep Axle Side Link Separation at 25% of Tire Diameter
  • Keep Frame Side Link Separation at 12.5% of Tire Diameter
  • Lower Link Angle should be angled between 5 - 10 degrees to frame
  • Converging Angle of links should be no less than 40 degrees


-G
 
Is there a corraletion between length of links vs tire diameter?
 
yellowK20 said:
Is there a corraletion between length of links vs tire diameter?
Click to expand...

No... only between the uppers and lowers themselves. Upper links are usually shorter and are roughly 2/3 the length of the lowers. This affects caster-change on the front end quite a bit.

As links get long, you lose a lot of strength for your bending modes, etc. When you play around with the "Materials" tab you will see how hard it is to get good "FS" (Factors of Safety) with long links.


Once you get a few designs that look "close" just post up screenshots and it will be easy to give feedback.


-G
 
FOR MUD said:
I know the wider you go the more the stability.....So I guess every bit helps. I would guess you will find you'll need run some kind of sway bar.
Click to expand...


Sway bar is something I wouldn't be opposed to but probably not really an issue for this trucks uses. As it will never see pavement , so no real abrupt cornering .

That being said lots of body roll sucks on side hills and I will be doing that :/
 
yellowK20 said:
Sway bar is something I wouldn't be opposed to but probably not really an issue for this trucks uses. As it will never see pavement , so no real abrupt cornering .

That being said lots of body roll sucks on side hills and I will be doing that :/
Click to expand...

If you keep your Roll Axis high and as close to the CG height of the truck, things will be more stable..... of those two values are wildly different (Very low roll axis for example) the body will want to "flop" over on the suspension and lay there on side-hills, etc.


-G
 
Greg72 said:
No... only between the uppers and lowers themselves. Upper links are usually shorter and are roughly 2/3 the length of the lowers. This affects caster-change on the front end quite a bit.

As links get long, you lose a lot of strength for your bending modes, etc. When you play around with the "Materials" tab you will see how hard it is to get good "FS" (Factors of Safety) with long links.


Once you get a few designs that look "close" just post up screenshots and it will be easy to give feedback.


-G
Click to expand...



Ok cool , that's why I am asking I don't really want super long links , we do a lot of break over type stuff on river banks and what not , and drop off ledges , ice in the rivers ect so trying to keep them no longer then the tcase crossmember , I have a really stout doubler crossmemebr and I'd like to tie my lower link mounts into it. And then
 
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