Four link ?

[jlalonde]

So i'm planning on building a double traingulated four link on my yj. I've read alot about this, but i'm still a little confused about what numbers (on average) to shoot for on the calculator? So i was wondering what other people did? Did you even use a calculator? IF so what numbers are you runnning? Thanks for the help!


Justin

 

[aweber]

I run 73% AntiSquat and would not change it for the world.

Go to Pirate4x4.com and in the general Tech section, search for the god of Suspension thread.

 

[Farm Boy]

Lower link lenght as long as reasonably possible
Lenght of uppers 70% of lenght of lowers.
Keep the uppers as flat as possible.
When building a 4-Link on an existing vehicle (compared to a full buggy), you are severely limited as to where things fit on the frame.

When I built mine, I followed the first 3, have no idea of the AS, roll center, roll axis, blah, blah, blah or any of the other #s in the calculator as I never used it. I am very happy with the way it handles.

Unless they've cleaned up the "god of suspensions" thread in the last few years, take it with a grain of salt. Last I looked at it there was more bitching, whining and ego-tripping than real tech. The tech is there, just hard to find.

 

[Kunker]

Unless they've cleaned up the "god of suspensions" thread in the last few years, take it with a grain of salt. Last I looked at it there was more bitching, whining and ego-tripping than real tech. The tech is there, just hard to find.

Unfortunately, last time I looked it was the same thing.

Jon outlined the major points to hit on, but the best advice is probably to build in as much adjustability as you can, allowing you to see what works and what doesn't.

 

[jlalonde]

Thank's for the help. And yes it still takes little bit to get through. So the only thing i'm unsure of is what "roll axis angle" is, and what degree I should be around. From what i can get it show the amount of rear steer?

 

[Farm Boy]

Roll axis is the imaginary line that would be made through the points of intersection of the uppers and lower: enxtend lines from the 2 uppers until they cross (point should be behind the axle). Now do the same for the lowers (point should be up by the t-case) Make a line thru these two imaginary points and that is the roll axis.
"roll axis angle" would then be the angle of this line as viewd from the side of the truck.

IIRC it and COG determins side hill stability (could be wrong though). The flatter and lower the better
I think rear steer is more controlled by the length of lower links and their change of angle (and effective lenght) thru the cycle of the axle. This is why it is important for them to be as long as possible.

 

[jlalonde]

Thank's for the info. I think i have it figure out, all that's left is to build it.

 

[Mitko]

Just of quriousity I went to pirates web and briefly read the god of Suspension thread. Yea, Farm Boy is right - a lot of BS and bitchin there, hard to find and substract usefull informatioin.
Found something else into the web which might help:
http://mysite.verizon.net/triaged/4linkcalcv15html/index.html
http://www.4wheeloffroad.com/techarticles/suspension/131_0307_four_link_suspension_part_2/index.html
I dont know are they good or helpfull, dont even know what all those things mean. Not planing to built any long arm four link suspension any time soon as my truck alredy has it and it is build by better engineers than the threads authors.