Shackle Angle

[kozak]

After doing a bit of searching, I am unsure of what the right answer is for an ideal shackle angle. I have read 45-60 degress, is best, but have also seen people setting them to all kinds of different angles. I am doing a solid axle swap right now, with the truck at ride height the shackle is a 22 degree angle. At full droop it doesn't go anywhere near past vertical. Sound about right ?
If I am correct, I don't want the shackle to go past vertical at full droop, or I am in trouble.
I have mock up mounts right now, so if the shackles are not okay as is, I can make the rear mounts to compensate for it.

 

[NMB2]

you can see my shackle angles in this pic.

 

[slammer67]

you got weight on those jackstands?
you need to get all the weight on the springs to see for sure.
if that's with all the weight on, I'd move your hanger back some.
I like 45 degrees or something close.

here's mine on the rear

and the front

hard to tell from that pic but I had a little more angle than yours, I have adjustable holes in mine , but if I move the shackle to the back hole, I had a little too much angle.

Those pics were post SAS over a year ago, I went out and checked just now and I have maybe a 40 deg angle now.
Yours will settle a bit, es-ecially if you've just done the SAS.
if everythings already welded up, I'd say drive it around awhile and I bet your springs will sag and give you a better angle, if its not enough, then go back and redo your mounts/crossmember.

Its not that big of a deal since your springs are sorta flat, like mine, but if you had super flexy, arched springs with that angle, your shackle could go negative and get stuck in the backward position - and that sucks.
plus a better angle allows the springs to work better.

good luck

 

[kozak]

Thanks for both your help. The pictures help alot.
That is with the weight on the springs, I left the jacks under just in case the worst happens. Looks like I will be repositioning/designing my rear mounts. Id rather get it right the first time. I am using Explorer leafs, with one main leaf with the eyes cut off from another pack mixed in under the main leaf. I have the shackles in the front. 5.5 inch shackles.
Just a thought, do you think I should set it to around say 40 degrees, or a bit less to allow for any sagging/settling of the springs ?

 

[NMB2]

you are measuring wong. You want an angle finder and make the shackle roughly 90* to the spring. Then it will sag little. but with used springs you may want to put a little more angle on it.

 

[Bray D]

you are measuring wong. You want an angle finder and make the shackle roughly 90* to the spring. Then it will sag little. but with used springs you may want to put a little more angle on it.

This.

You have to measure the shackle angle relative to the spring.

 

[kozak]

Okay, so what your saying is, that in the picture below I want my shackle and spring to form the angle of the angle finder displayed ?
Since I am using used springs, should I make the angle a few degrees over 90 ?
(by the way, the rear mounts are un-bolted, thats why the shackle angle is like that in this pic)

 

[NMB2]

Okay, so what your saying is, that in the picture below I want my shackle and spring to form the angle of the angle finder displayed ?
Since I am using used springs, should I make the angle a few degrees over 90 ?
(by the way, the rear mounts are un-bolted, thats why the shackle angle is like that in this pic)

exactly.

 

[slammer67]

yeah, but if he goes 90* to the spring, He'd have his shackle almost straight up and down.

kozak - it looks like you have better angle in those last pics, maybe it settled some, I'd say leave it where it is

 

[blue88b2]

that's good! If your springs are relatively flat and that's with weight on that's really good! if they have arch to them ( like mine do) at compression when fully flexed there is a chance the can cam over forwards ( like mine did before i changed the angle). Just a heads up. because that's how i did mine at first then had to redo after some testing.

-jason