4 link

[dcman008]

I was wondering if any one can explain to me how 4 link works. please take note that i'm an idiot. i don't know much about suspension, pics wood help a lot. thanks

live long 91 corica

[michael]

Go to the skunkz section and check out all the trucks...they all have them on the rear. Here is one. It's the four links that attach the rear end to the truck.
http://race-dezert.com/skunkz/newline/38.jpg

Michael <A target="_blank" HREF=http://jmartin.net/goose>jmartin.net/goose</A>

[84toy]

The two links on the outside keep the axle in place front to back. The center links (shaped in the triangle) hold it in place from side to side. Having two of the links on the top and two on the bottom keep it from twisting.

Jason

[NorCal_Prerunner]

Questions:

Should the lower links be angled inward or parallel? Advantages, dis-advantages? Why?

How does one determine lower link length?

It's never too late to be what you might have been....

[singlehanded]

So should the ouside links be parrallel with the frame? And what is the angle /degree of the center links usually at or is it usally different? Is the mount above the center section of the housing usually higher then the other side of the links when truck is not moving?

local

[ntsqd]

If you angle the upper links and make the lowers parallel to the frame, then you have a relatively simple to find (& control) roll center. If you angle the lowers too, then you have a not as easy to find (or control) roll axis.

Search the previous postings on books to read. The Herb Adams book "Chassis Engineering" is a good place to start. Keep in mind that these books are written with regard to road racing. It's an HP book so you should be able to find it at a Borders or B&N. Amazon also carries it. ISBN 1-55788-055-7

TS

"Teach you all I know and you're still stupid"
-- Howdy Lee

[Kbach66]

In regards to the roll center, how important is roll center in a truck? I understand that it is fairly important in a road car aplication, which has a limited amount of travel, low CG, etc. But do you have to locate the roll center as accurately in a truck which might have anywhere from 20-40" of travel?

Also, on another design aspect...what is the common size of heims used in most class 8 or trophy truck type 4 links? Both for the lower arms, and upper links. I've run some numbers on it, and it seems like they only need to be 3/4 or so for the lowers...but I see a lot of 1"+ heims in some of the trucks I look at. I'm sure some of you fabricators have some methods to your madness.....care to help a brother out!!

Thanks.

[Kritter]

Most use 1.25 in heims, which are definitly overkill...aircraft landing gear uses 1.25"!!!! Lack of design analysis is why a lot of people use the overkill method.

Kris

<A target="_blank" HREF=http://www.dmsrace.com>www.dmsrace.com</A>

[BIG_FAT_LOSER]

LONG LIVE THE LEAFSPRING!!!!!!!!!!!!!!!!!

<font color=red>PAT KAPKO</font color=red>
<font color=yellow>Self appointed King of ghetto fab/Rally rookie</font color=yellow>

[partybarge_pilot]

Bigger Hiem= more surface area= longer life. To a certain extent not counting mud and other contaminants. A .75 hiem is strong enough to hold up just about anything. A bigger hiem will last longer and have less chance of pulling out.

[ntsqd]

Controlling the roll center's location helps determine if the vehicle wants to flop on it's side during a 'scooby' landing (Laughlin Rd Crossing), or if it wants to gather the suspension back under it and keep going. The quicker, during suspension compression, that the roll center gets above the CG the harder it will be for the rig to flop since the CG would have to go 'uphill' when most of the inertia is downwards.

TS

"Teach you all I know and you're still stupid"
-- Howdy Lee