I'm relocating an axel on a 79 F-350 forward and doing a shackle flip at the same time. Should the shackle be straight up and down with the weight on it? Whats the best angle? I can set it unloaded also to max out droop and that was my first plan but now I'm getting a little out of my leage. How do I know where the best location for the rear shacke hanger is?

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I'm relocating an axel on a 79 F-350 forward and doing a shackle flip at the same time. Should the shackle be straight up and down with the weight on it?

Seriously :confused:

Wow.

no to straight up and down, that will limit droop

no to straight up and down, that will limit droop

This is what I have. Front is cut and has 3" Skyjacker spring with one leaf removed. Relocated cab mount to clear 40's. It works nice. The rear has stock rear leaf with bottom overload and one leaf from the middle removed. The block is gone. I'm getting my rear lift from mounting the front hanger foward under the cab where the frame is lower and from the shackle revesal. I will only have a fuel cell ,battery and a few tools on the rear frame with no bed so It's light. The main thing I care about is droop. Whats the best way to set it up to max out droop? If I lift the rear shackle mount up as high on the frame as I can to max the angle for droop then the angle of the shacke winds up straight when I load it. Just dosn't seem right.

This is what I have. Front is cut and has 3" Skyjacker spring with one leaf removed. Relocated cab mount to clear 40's. It works nice. The rear has stock rear leaf with bottom overload and one leaf from the middle removed. The block is gone. I'm getting my rear lift from mounting the front hanger foward under the cab where the frame is lower and from the shackle revesal. I will only have a fuel cell ,battery and a few tools on the rear frame with no bed so It's light. The main thing I care about is droop. Whats the best way to set it up to max out droop? If I lift the rear shackle mount up as high on the frame as I can to max the angle for droop then the angle of the shacke winds up straight when I load it. Just dosn't seem right.
at ride height it should be a little less than 45*. search and you will see how it should look under load.

use a longer shackle

use a longer shackle

:confused:
The way he is explaining it (to me) seems that the shackle is like "l" when loaded where it should be like "\". Wouldn't making a longer shackle screw it up more?

:confused:
The way he is explaining it (to me) seems that the shackle is like "l" when loaded where it should be like "\". Wouldn't making a longer shackle screw it up more?

longer the shackle at a proper angle will provide more droop.

and make sure its not a "sucky angle":flipoff2:

longer the shackle at a proper angle will provide more droop.

and make sure its not a "sucky angle":flipoff2:

Sounds to me like he's only worried about the sucky angle.

at ride height it should be a little less than 45*. search and you will see how it should look under load. I got it sitting at about 10 but I'll add some more befor I burn it in. I went wrong because I was trying to max out droop with the rear hanger and shackle loose from the frame. I could get a nice angle to follow the spring but I didn't take the fact that the shackle actually swings down
thru it's arch which is more important than just angling toward the spring. Thanks for the help.

I always tried to set it at 90* in relation to the leaf with the weight on it.

well that may or may not be good.
all it has to be able to do is move back far enough to allow the spring to straighten/flatten out.
any more then that and you are leaving droop on the table as well as adding spring rate due to the shackle angle

Mine is at about forty degrees at load. Which, is no small coincidence, just about where you want it.

I found that 30 degrees angle with trucks weight resting is decent for flex and droop.

I always tried to set it at 90* in relation to the leaf with the weight on it.

From what I have always found, this is usually a pretty good indicator. We just setup my buddies YJ and he more or less used this as his indicator. The thing fawkin flexes like mad too. It also has a Heinz 57 spring pack up front too tho, with yota, rancho wagoneer and stock YJ springs all mixed together. He's never had his shackles bind up when the springs are squished and compressed. He also hasn't had them flip around when fully drooped either. Which fawkin sucks btw.


well that may or may not be good.
all it has to be able to do is move back far enough to allow the spring to straighten/flatten out.
any more then that and you are leaving droop on the table as well as adding spring rate due to the shackle angle

Unless he has uber stiff springs, in which case, they prolly wouldn't squish out flat to begin with, specially with no bed and all.....but more or less, that is also a good indicator as above, in my opinion.

Just outta curiousity mj, how do ya add spring rate due to shackle angle?

From what I have always found, this is usually a pretty good indicator. We just setup my buddies YJ and he more or less used this as his indicator. The thing fawkin flexes like mad too. It also has a Heinz 57 spring pack up front too tho, with yota, rancho wagoneer and stock YJ springs all mixed together. He's never had his shackles bind up when the springs are squished and compressed. He also hasn't had them flip around when fully drooped either. Which fawkin sucks btw.




Unless he has uber stiff springs, in which case, they prolly wouldn't squish out flat to begin with, specially with no bed and all.....but more or less, that is also a good indicator as above, in my opinion.

Just outta curiousity mj, how do ya add spring rate due to shackle angle?

Here's a good article: http://www.afcoracing.com/tech_pages/leaf.shtml

And a diagram to splain it:

http://www.supermotors.net/getfile/662753/fullsize/leaf-spring-shackle-angle.gif

yea, that makes it a lil easier to understand.....that diagram helps too...

I've just done the same on my F250 .I helps to know what the eye to eye measurement is when the trucks weight is on it.You could even just put spring on ground and drive on it to get some idea.But it seems if you fit front of spring in hanger and lift the rear it should be about 90 degrees un sprung.Then when you load the weight on it shackle will move back to about 30 degrees.
Bit of trial and error ,but tack welding hanger on instead of drilling lotsa holes helps,doing on side at a time.
If angle is a bit too much then add longer shackle.