I need to find as much info as possible on designing a 4 link for my rear end as possible. I want all the physics and formulas and as much info as possible. Are there any books or anything out there that can teach me any of this stuff??? Money is no object and I want the best education (within reason) on designing and making a 3 or 4 link. All you who are so well educated in this please divulge your sources of education. :beer:

Search for the Suspension God thread by CalPolyStud. You might have already seen it, the first 7 or so pages are damn informative. Just don't bring it back, people will hate you.:D

By the way, I customed a 4-link rear that kicks ass IMO. Depending on what vehicle you are planning to fab it for, I could give you a few numbers to start w/. The baddest 4-link I have seen is DesertToys, sweet!

I appreciate the help and all but I want books. I am not disregarding the quality of info from here god knows I have learned just about everything I know about 4x4's here. I have a hard time following something as complex here as I would in a book. There has to be some source of info out there y'all had to learn it somewhere! :confused:

:usa: I can understand what you mean.

I have read so many articles about 4 link in the mags and I want to convert
my rig to 4 link front and rear.

I am a bit nervous about it because if it turns out wrong I don't want to
have to scrap all the time, money, and effort. Running a big lift in my 4Runner and I have been arguing with myself about
either National Springs or custom 4 link.

So far the most info I have gotten is from the mags and they don't list
any books. Curious to see if anyone has heard of a book about this.

:usa:

I just wanted to add that today I called OffRoad Unlimited and asked
if they knew of any 4 link books out there.

I figured it was a smart move since a few years ago they built the
4 door Dodge Dakota with 4 link F/R.

They said they didn't know of any books and all they learned was from
Desert racers and trial and error.

:rolleyes:

Thanks for the info bud :thumbsup: If I catch anything I will let you know. I am definitely on the search for any and all info on anything. I got autocad 2k but have no fawkin clue what the hell I am doing. :emb: I can see how a business would not reveal their sources so they dont lose business to average joe but WTF!

I found one book on chassis and suspension design from offroad.com's book review written by Herb Adams the title is: "Chassis Engineering/Chassis Design, Building & Tuning for High Performance Handling" I'll let you know whatr I think. the URL to the review is


http://rubicon.off-road.com/bvreviews/chaseng.html

Hope this helps someone besides myself.

Originally posted by scouter77
I found one book on chassis and suspension design from offroad.com's book review written by Herb Adams the title is: "Chassis Engineering/Chassis Design, Building & Tuning for High Performance Handling" I'll let you know whatr I think. the URL to the review is


http://rubicon.off-road.com/bvreviews/chaseng.html

Hope this helps someone besides myself.

I bought that one a year or two back..

It's definitely oriented towards circle track and straight line stuff.. nothing about long travel 4-links and the hazards of too much anti-squat when you have 3' of wheel travel. :D

At least it tells me how to setup my Scout so it'll corner like it's on rails.. if I could just talk the body into doing the same...

The Herb Adams book is pretty good from what I hear.

Tom- I am glad you like it :D That makes me feel better about buying it. I value your opinion. And I understand what you're saying about the body! With the top on its like driving a sail boat!

Pig- I hope he knows what he is talking about! He was a suspension designer from GM! He took his wive's car and turned it into a Trans-Am (like Can-AM style) car and whoopt serious ass. From what I hear you might be able to help on the 4 link stuff abit too ;)

Anyway I cant wait till it gets here God knows all the millions of SAE periodicals didnt help me much from the ASU library. And all the other books there were kind of way off on the aspect of what I was looking for. I went to a public library too and it was all info on how to chrome my frame and make it look cool woohoo! :rolleyes: Anyway I hope this book helps me some if there are any other suggestions please dont hold back hell the worst it could do is either get you flamed or up your post count :)

there is a book by Miliken that is supposed to be the 'one'
the chev power manual at your local chev parts counter has a ton of stuff but it is circle jerk/track oriented and math heavy but no indications of numbers to shoot for. Mustang performance Handbook 2 has a bunch of laymans explainations of trends/effects of various settings.
I have the relavent pages of the power manual and mustang books scanned into my webshots
http://community.webshots.com/user/ausername11 not sure if the link works as they have redone their sites recently

Yeah Race car vehicle dynamics by Miliken and Miliken is the most comprehensive book on the subject. It explains everything from a theoretical standpoint so that if you are smart and spend enough time at it you can really understand what you want. The other books are oriented towards pavement. They tell you how to do things but they don't ell you why. Sometimes what you want on pavement is not what you want on the road so it is really nice to know why. The herb adams book is better than Carrol smiths books from this perspective.

Thanks for the reviews and info posted so far. It is greatly valued. Amazon will have most of what is posted so far I assume??

Originally posted by Gordon
Yeah Race car vehicle dynamics by Miliken and Miliken .


Just ordered it from amazon 3-5 weeks since its a special order :cry: oh well I can wait that long I suppose :D but in 3-5 weeks classes will be started and I wont want to study more stuff than already required. :shrug: oh well tis life.:smokin: :smokin:



I have heard of this book before from a buddy who does autocross (like slalom) but never thought it would be something I was interested in until I heard more about it and at $80 thats one school textbook! oh well good reading is always worth a little extra ching. Thanks to all who helped this should be enough to get me in some trouble

Originally posted by scouter77
I found one book on chassis and suspension design from offroad.com's book review written by Herb Adams the title is: "Chassis Engineering/Chassis Design, Building & Tuning for High Performance Handling" I'll let you know whatr I think. the URL to the review is


http://rubicon.off-road.com/bvreviews/chaseng.html

Hope this helps someone besides myself.

good book, ive read it a few times, even outlined the high points......

the only answer i havent found is do i want more or less anti-squat...... in straightline anti-squat is the shit....... just havent decided what percent of anti-squat ill be lookin for.... but i will :D


ohh the satchel link seems to be the best setup...... only altered in some ways to better suit our needs....

ohh the satchel link seems to be the best setup...... only altered in some ways to better suit our needs....


Sweet thanks for the tip. This book should be here tomorrow or the next day. I have to put my life on hold So I can read them :mad:

Originally posted by badassjeepguy
ohh the satchel link seems to be the best setup...... only altered in some ways to better suit our needs....



What do you mean by slightly altered to better suit our needs? Besides the fact the links need to be longer? I got the book but haven't looked closely. Does it cover rear steer or is that a 4x4 only type problem??? It definitely looks like awesome reading and I should be doing that instead of this.

:D

It is refered to as over and under steer in the book.

I read it and it makes sense. I wasnt exactly going into this whole thing totally blind. I know what caster camber toe and some other forces have on a vehicle and its handling. I guess The link dynamics, placement and their effects on the axle are my biggest concerns. After reading I only have the same questions as the others. How much anti squat do I want??? Also what about the front??? Anti squat or squat??? I am thinking a 3 link with a panhard bar I guess? Roadracers tend ot stay away from all wheel drive or something??? :D fawkers! Still in the EARLY stages of research as Far as I feel I need to be. It doesnt really seem that hard but it also seems like I am missing a huge chunk of the pie somewhere... I have made some not quite to scale models and actually see the dynamics of how what link placements do what to the vehicle. I suppose I need to do a scaled version for realistic purposes. :confused:

Originally posted by scouter77




What do you mean by slightly altered to better suit our needs? Besides the fact the links need to be longer? I got the book but haven't looked closely. Does it cover rear steer or is that a 4x4 only type problem??? It definitely looks like awesome reading and I should be doing that instead of this.

:D well they are all about alot of anti squat.... im not so sure if that is what we want.... havent decided on that either way..

the lower links goin in, may, depending on rig, cause some interferance....

thats all i can remember right now....

i think what you guys call 'rear steer' would be refered to as 'roll steer'
my road race book states something like anti squat approaching 50% causes problems, but they are talking at speed.

Agreed with the roll steer terminology. From what I read it seemed like 100% antisquat was somewhat normal??? I could be wrong. One new question I have is what does link angle have to do with anything? From what I understand the more parallel to the frame the better according to the books but I dont see why?

Originally posted by scouter77
Agreed with the roll steer terminology. From what I read it seemed like 100% antisquat was somewhat normal??? I could be wrong. One new question I have is what does link angle have to do with anything? From what I understand the more parallel to the frame the better according to the books but I dont see why?

yeahh 100% is there norm, but i dont think that is what we want though.

well from what i can remember link angles.... upper and lower should intersect somewhere around mid vehicle and below the cog... this is what they call ummmm roll axis... so in car where clearance for rocks doesnt matter... you can run the arms lower, giving you a low roll axis.....


what i can see is...... setup coil overs as close to wheel as possible.... no more than 20 degrees in at the top towards the frame.... im lookin at 15 degrees.... mount lower arms as wide on axle as possible, with the frame mounts going in.... upper links come off the center of diff... angled out to the frame either paralel or angle up at the frame. ( if angled up, your roll axis will be higher) then the 3 to 4 rule.... if the lowers are 4 foot, the uppers should be around three foot


ahh i just remembered.... the shorter the links the less antisquat, the longer the links more anti squat..... so that is why the RE long arm has less squat due to longer arms.....


now ill tell ya i am an amature, so ill take all advice from others.... go easy on me you damned engineer's :D

Originally posted by badassjeepguy


ahh i just remembered.... the shorter the links the less antisquat, the longer the links more anti squat..... so that is why the RE long arm has less squat due to longer arms.....




From what I have seen and read I disagree. The length does play a factor but the biggest part that sets anti squat is how far the distance is vertically te links are mounted. Think if the top links were switched places with the lower links on the satchell setup. You would have squat or negative antisquat. BUT If you say shorten the top (triangled) links I think I agree. :emb:

I think you may be reading into this too much. last year I went to school for chassis enginering at wyo tech and I went all out on my first off road prodject. I built a full tube chassis lang travel ranger, and yes I was very sceptical at first on how the suspension would turn out. But eventualy I said screw it and decided to trust my judgment and it worked. like you I sat and thought about it for a long time and still was overwelmed by all the info I found because alot of it contrdicts itself. I too read that chassis enginering book, and yes it probably helped me out alot, but that and eveery other book I read was about race cars, nothing about trucks, you know why because most of all the science on car suspension in refined truck suspension. Its true when I was in school they even agreed, alll the trick suspension ideas for cars came from the off-road world. unlike cars trucks dont care if the axel shifts to one side under articulation or a bunch of other things the suspension does (anti squat, roll angle, etc.) I dont think as an amature you need to worry about it, you can biuld alot of adjustment into your prodject for you to spend all the time in the world tuning your suspension. ex. extra mounting holes, threaded hiem to adjust length, and there is tons of other things you can do.
Ok I think I starting to preach a little much!!
hears what worked for me, I went with a triangulated four link in the rear. My lower liks are 60" and my upper links are 45". lowers are as wide on the housing as possible and just onder the frame up front. my upper links are on the middle of the housing and just under the frame as well. frame rails are 30" apart. the hight is 12" between the uper and lower mounting points on the housing.
the links are not parallel the uper links areangled down thin helped keep the pinion angle up, pinion angle is one thing that I thought was very important. with unequal length links the pinoin will or can roll alot. but you can make it stay prety well aimed at the t-case by playing on your cad program with the link angles, thats how I eventualy came up with something. Also by going with a a triangulated four link you dont need a pan hard. this worked out for the best for me because when articulated the axel shifts side to side which helps the wheel tuck inside the wheel well and not into it. now dealing with the coilover shocks i mounted them 1/3 forward on the lower links, this took my 16" travel shocks and let me have 24" of travel at the wheel.
Ok Im sick of typing if there is any questions I can help with just ask!!

Originally posted by scouter77



From what I have seen and read I disagree. The length does play a factor but the biggest part that sets anti squat is how far the distance is vertically te links are mounted. Think if the top links were switched places with the lower links on the satchell setup. You would have squat or negative antisquat. BUT If you say shorten the top (triangled) links I think I agree. :emb:


ooops i was tired........ and had a few :beer: 's

straight from the book......

In attempts to gain MORE and MORE anti squat, it soon becomes apparent that the effective swing-arm length of the rear suspension will become shorter and shorter. like most adjustments on a car, you reach a point of compromise


so, for less antisquat you want a longer arm, which will also help with brake hop

as for the top shorter, yeahh i agree, like i said up a few, 3 to 4 ratio..... at least thats what im seeing and have been told

"effective swing arm length" is the imaginary link from the intersection point of the upper and lower links to the axle. has nothing to do with actual link lengths (though the actual link lengths determine how much the intersection point changes through the travel)
having the arms parallel to the ground is to limit roll steer.
if the chassis drops 1" down on PS and rises 1" up DS, the parrallel to the ground links will shorten the wheelbase by the same amount.
if the arms sloped high at chassis and low at axle in the same 1" roll scenario the PS wheel base will shorten and the DS will lengthen until the arm passes through parrallel with the ground.

if you have looked at some of the shapes that people are using on their control arms lately you will notice they are using curved arms to keep them out of harms way while still keeping the suspension geometry where they want it.