• RME Gear & Apparel

My 4 Link buildup

Caleb

Caleb

Well-Known Member
Location
Riverton
for anyone that wants the link calculator you can get it from my site here you do need excel to use it. There is Java online version I am working on putting up on my site too...
 
Hickey

Hickey

Burn-barrel enthusiast
Supporting Member
Location
Grantsville, Utah
Hickey said:
Original measurements on my 4 link were like this. It gave me 119% antisquat.
attachment.php
Click to expand...
I messed around with the measurements. In this next figure, I moved the UCA mounts at the frame up one inch, it gave me 103% AS. Then I moved the LCA mounts down one inch, this gave me 79% AS :eek: That a crapload of difference for just one two more inches of vertical seperation at the frame.
attachment.php
 
Last edited:
Greg

Greg

I run a tight ship... wreck
Admin
Location
Grand Junction, CO
OK, I'm getting all my parts gathered so I can start assembling the 4 Link. Here's what I have & where I got it-

Upper & Lower Links, 1 1/4" Rod Ends on lower links, 7/8" Rod Ends on upper links, threaded inserts & jam nuts, misalignment spacers, YJ Bushings for frame end of links and some misc. brackets. I got all those parts from RockLogic.

I picked up a set of factory 6 cyl. TJ front coils from Blacksheep.

Parts.jpg


Coils measure about 16.5" unloaded and around 12" loaded.

CoilTapeMeasure.jpg


1.75" x .330" Lower Links & 1.5" x .250" Upper Links.-

Links3.jpg


LowerLinkTapeMeasure.jpg


UpperLinkTapeMeasure.jpg
 
Greg

Greg

I run a tight ship... wreck
Admin
Location
Grand Junction, CO
I built the Bridge & welded it to the axle over the weekend. Specs are:

3"x3"x3/16" Square Tube on the bottom.

3"x1"x1/4" Rect. Tube on the top.

AxleBridge5.jpg


AxleBridge4.jpg


AxleBridge2.jpg


AxleBridge1.jpg


I'm trying to keep it simple & beefy. Most of the welds look pretty horrible... so it's gotta be strong, right? :ugh: :eek:

Thanks to my buddy Erik for letting me use his metal bandsaw! :cool:
 
Maverick

Maverick

old-school
Location
Anywhere, thanks to my geeky droid
Greg said:
I built the Bridge & welded it to the axle over the weekend. Specs are:

3"x3"x3/16" Square Tube in the middle.

3"x1"x1/4" Rect. Tube on the top.


I'm trying to keep it simple & beefy... and most of the welds look pretty horrible, so it's gotta be strong, right? :ugh: :eek:

Thanks to my buddy Erik for letting me use his metal bandsaw! :cool:
Click to expand...

Lookin' good! Beefy too (that's a technical term). Actually, "Hell for Stout" is the term we used to use.

(Thinking out loud here, I think this stuff is in the spreadsheet too.)

Upper links are usually in tension. Arch is about 6" high, right? 3" front to back, so the force on the rearmost welds is roughly twice what's in the links. Divide that by the area of the welds (or 3/16" whatever is thinnest) and you'll have your approximate stress.

Ass-u-me-ing 40" tires and 4000lb rig, you've got moment in the rear axle of 6600 ft-lbs if you're on a vert ledge. Add shock loading to that if you want, say 1.5 to 2x. So, 10,000 ft-lbs. Alternatively, 200 ft-lbs from an engine x 100:1 gearing puts you at 20,000 ft-lbs (if you're hammer down, not counting shock loading).

6" arch takes that to 20,000 (or 40,000) lbs of force in the upper links. ( I haven't checked the thread to verify 6") So, 40,000 lb -80,000 lbs force on the welds over the whole thing, 20K per side...(or double that, 40K, if you're hammer down)

Looking at one side: 3" cut at an angle, assume 4.25" along weld per side (actually more). 3/16" metal, so that's .8 square inches. Add in the contribution from the side welds (2*3"*3/16" x 2/3= .75 sq in) (side welds only contribute 2/3) and you get between 13,000 and 26,000 psi in the welds. You should be fine.

YMMV, these are all theoretical numbers, I'd compare them with actual results from other rigs built like yours.

Oh ya, SUWA can pound sand. :rofl:
 
James K

James K

NO, I'm always like this
Location
Taylorsville, Ut
Maverick said:
Lookin' good! Beefy too (that's a technical term). Actually, "Hell for Stout" is the term we used to use.

(Thinking out loud here, I think this stuff is in the spreadsheet too.)

Upper links are usually in tension. Arch is about 6" high, right? 3" front to back, so the force on the rearmost welds is roughly twice what's in the links. Divide that by the area of the welds (or 3/16" whatever is thinnest) and you'll have your approximate stress.

Ass-u-me-ing 40" tires and 4000lb rig, you've got moment in the rear axle of 6600 ft-lbs if you're on a vert ledge. Add shock loading to that if you want, say 1.5 to 2x. So, 10,000 ft-lbs. Alternatively, 200 ft-lbs from an engine x 100:1 gearing puts you at 20,000 ft-lbs (if you're hammer down, not counting shock loading).

6" arch takes that to 20,000 (or 40,000) lbs of force in the upper links. ( I haven't checked the thread to verify 6") So, 40,000 lb -80,000 lbs force on the welds over the whole thing, 20K per side...(or double that, 40K, if you're hammer down)

Looking at one side: 3" cut at an angle, assume 4.25" along weld per side (actually more). 3/16" metal, so that's .8 square inches. Add in the contribution from the side welds (2*3"*3/16" x 2/3= .75 sq in) (side welds only contribute 2/3) and you get between 13,000 and 26,000 psi in the welds. You should be fine.

YMMV, these are all theoretical numbers, I'd compare them with actual results from other rigs built like yours.

Oh ya, SUWA can pound sand. :rofl:
Click to expand...



man :eek: :ugh: .........................and I thought that I over thought mine :rofl:
 
Greg

Greg

I run a tight ship... wreck
Admin
Location
Grand Junction, CO
Maverick said:
Lookin' good! Beefy too (that's a technical term). Actually, "Hell for Stout" is the term we used to use.

(Thinking out loud here, I think this stuff is in the spreadsheet too.)

Upper links are usually in tension. Arch is about 6" high, right? 3" front to back, so the force on the rearmost welds is roughly twice what's in the links. Divide that by the area of the welds (or 3/16" whatever is thinnest) and you'll have your approximate stress.

Ass-u-me-ing 40" tires and 4000lb rig, you've got moment in the rear axle of 6600 ft-lbs if you're on a vert ledge. Add shock loading to that if you want, say 1.5 to 2x. So, 10,000 ft-lbs. Alternatively, 200 ft-lbs from an engine x 100:1 gearing puts you at 20,000 ft-lbs (if you're hammer down, not counting shock loading).

6" arch takes that to 20,000 (or 40,000) lbs of force in the upper links. ( I haven't checked the thread to verify 6") So, 40,000 lb -80,000 lbs force on the welds over the whole thing, 20K per side...(or double that, 40K, if you're hammer down)

Looking at one side: 3" cut at an angle, assume 4.25" along weld per side (actually more). 3/16" metal, so that's .8 square inches. Add in the contribution from the side welds (2*3"*3/16" x 2/3= .75 sq in) (side welds only contribute 2/3) and you get between 13,000 and 26,000 psi in the welds. You should be fine.

YMMV, these are all theoretical numbers, I'd compare them with actual results from other rigs built like yours.

Oh ya, SUWA can pound sand. :rofl:
Click to expand...


Woah!! :eek:

Thanks... I think... my head hurts! :D :cool:
 
R

rockdog

Guest
um

:eek: :eek: :eek: oh my , did you get all of that greg ? i was thinken of four linken the rear of my truck, but now i can see i'm in way over my head on that!!
 
Greg

Greg

I run a tight ship... wreck
Admin
Location
Grand Junction, CO
More progress tonight...

AxleBridgeLinks.jpg


AxleBridgeLinks2.jpg




My Links are on a 10-11* Angle, with everything mocked up about where it should sit once it's all done. Does that sound pretty good? I think so...
 
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