4-link rule of thumb (1 Viewer)

[LCOwner]

What sort of numbers should a builder be shooting for when setting up a 4-link for rock crawling? I could spend a lot of time searching but my web wheeling time seems to b getting less and less.

Anti-squat - less is better but what is an acceptable amount

Roll Center Height

Roll Axis

Instant Center X

Instant Center Y

Is there a general rule of thumb for these factors?

TIA

 

[woody]

are you building from scratch with a custom frame or are you working with your stock frame and stock driveline?

Really, space is 90% of what you end up with....while the formula's are nice to confirm your guesses, most of those are applicable in a very small portion of your wheeling, since they are largely derived from race car design.

IIRC, mine has about 85% in the antisquat, and I don't know that I ever calculated the balance....

Rear steer is another value to be concerned with, less is better.

 

[LCOwner]

Stock frame, 420/Mini tcase. Body is off the frame so I can do just about whatever I want. My goal is to not lose any interior space but I may clearacns a little for the drive train if needed.

 

[LC_Hamma]

What sort of numbers should a builder be shooting for when setting up a 4-link for rock crawling?

#1 make multiple link mounting points.
36" + upper link mounts
40" + lower link mounts
8" - 12" vert. seperation at the axle mounts w/ 3/4" heims
4" - 6" vert. seperation at the frame mounts w/ J. Joints

I'm running 38's w/ a 105" w/b. These are the figures I went with after searching multiple boards.
If you can do a true 4 link front with the F/2F, I'd like to see how you did it.
I had to use a track bar - difficult to triangulate due to space.

 

[milesstarkey]

where can i go to learn what all this terminology means?

 

[woody]

find my "and it starts" thread in Hardcore....lots of good and bad info in there...lol

http://www.pirate4x4.com/forum/showthread.php?t=204893 for the calculator, and more info

 

[milesstarkey]

woody, your "and it starts" thread doesn't have any pics after page 2. did you have to gut your axles to do the welding, or can i just weld to the axles as they are? i'm still confused about the difference between a 3 link and a 4 link. 4 link is l/\l right? so what's a 3 link? does the 3 link require a panhard bar?

 

[CruisinGA]

typical 3 link is
___ with the slant line being a single upper either from
|/ |
frame to axle, or lower arm to axle, and there is a panhard.

Then there is wishbone 3-link, which has an upper "wishbone" that travels in one plane only (up and down) and has a large spherical joint at the end that attaches to the axle, that allows for articulation. It has two parallel lowers. The wishbone controls side to side location of the axle.

 

[milesstarkey]

so four link is best? i read a thread where someone made a wishbone and wished he had made a four link. couldn't one just leave the axle on the leaf springs for location and weld the 4 link up and then remove the leaf springs and then install the shocks/coils whatever one's using?

 

[Mace]

No such thing as "best"
it is whatever fits the best for your application..


And yes, if the springs were not in the way of the links there is no reason you could not do it that way. However, when you run links it is VERY nice to move the axle back a bit..

 

[milesstarkey]

i was just going to flip the springs around and that's about all the further back i wanted to go. i did the same to the front already.

 

[BiffS]

If you can do a true 4 link front with the F/2F, I'd like to see how you did it.
I had to use a track bar - difficult to triangulate due to space.

Link dims: Uppers 32" lowers 37" LC 60 series axles. 318 wall cromo steel.

 

[LC_Hamma]

Badazz dude! Are those King shocks? Details? How close to the oilpan are those links? I assume you're not running a header (?) Did you have to modify the pass side bellhousing mount? When you ordered your shocks did you add some weight for a future winch? Thanks!

 

[LCOwner]

How much Roll Axis/Roll Over steer is acceptable? Correct me if I'm wrong. Isn't this the amount of rear steer 4 links get sometimes? My calculations have my proposed at 5°. Is that too much.

 

[BiffS]

Badazz dude! Are those King shocks? Details? How close to the oilpan are those links? I assume you're not running a header (?) Did you have to modify the pass side bellhousing mount? When you ordered your shocks did you add some weight for a future winch? Thanks!

Those are fox 18" air shox. the oil pan is nowhere near the links and there was no modification required to any of the engine or exhaust header details. The rear required much more re-location as i have an 80 cruiser and the gas tank had to be tossed in favor of a Jaz fuel cell. I needed the room where the tank was for the rear links to live.

the airshox (actually nitrogen powered) are near infinitely adjustable for ride height, so winch or other weights don't really matter much. In future, i'd get a shorter throw shock, 18" is a bit much.

(yes, slap me now).

 

[BiffS]

more pics:

 

[milesstarkey]

is it mandatory to gut the axle when welding to it?

 

[Full_M3tal]

Manly On The Ends, Because You Can Melt, Or Damage The Innel Axle Oil Seal, That Is If You Get It Too Hot.

 

[BiffS]

given the heat involed for good penetration. . . yes. it should be gutted. Bits of the residual oil in my housing caught fire. .. .

 

[Radd Cruisers]

given the heat involed for good penetration. . . yes. it should be gutted. Bits of the residual oil in my housing caught fire. .. .

Might consider bracing the housing on a welding table to keep it from moving out of true.

Think some places actually run a bar through the hosing and clamp it real tight.

Have been told its not really necessary to overweld or overheat the housing, stitch welding and allowing to cool might be the way to go.,

Plus I might incorporate a full length gusset on the long side of the axle to keep it true.

Looks like some great work.