Shackle Angle?

frankenyoter

frankenyoter

No Rain, No Rainbow
Joined
Mar 17, 2009
Location
DARK CITY
At the Flats I bent the main spring on the front when my shackle inverted. I took it off and for entertainment installed an extra rear up front. It looks like this rear spring has been modified to carry more of a load (more leaves than my stock rears). If I do a RUF I will remove some leaves or use the stockers.

At full droop should the shackle be at less than vertical to avoid the shackle swinging the wrong way?

This pic shows what I have now with just an empty housing laying on the spring and no weight on the spring.
RUF.jpg

And yeah a shop would be nice, it was cold yesterday.
 
I bent two sets of mains that same way. i ended up welding a small piece of pipe behind the shackle to avoid kickback. it doesn't affect articulation and I haven't bent a main spring since i did it. it's also easier to do and doesn't require any modifications to the shackle.
 
Your shackle angle looks too steep to me if that is the 'unloaded' position. They must be only 30 degrees from horizontal with the weight of the truck on them.
 
McCracken said:
I bent two sets of mains that same way. i ended up welding a small piece of pipe behind the shackle to avoid kickback. it doesn't affect articulation and I haven't bent a main spring since i did it. it's also easier to do and doesn't require any modifications to the shackle.
Click to expand...

I pondered something like this. Good to know it is proven to work.

drkelly said:
Your shackle angle looks too steep to me if that is the 'unloaded' position. They must be only 30 degrees from horizontal with the weight of the truck on them.[/quote

Thanks a concrete number to shoot for helps alot.
Click to expand...
 
I think the grammar in my sentence was incorrect, and my intended meaning came across wrong in my post. I meant that I am guessing ‘your’ shackle angle is probably only 30 degrees from horizontal with the weight of your truck on the springs? I am not a suspension engineer, but I don’t think that is a good shackle angle. I am guessing a good shackle angle is probably 70-90 degrees between the shackle and spring in the ‘loaded’ position.
Shackle angle.jpg
 
OK.

I was thinking that something like that would be best in the unloaded position. If the shackle was more like 45 loaded it would allow more drop in the suspension. Then if the springs were being pulled down from the force of the other side, the shackle would be vertical. In my thinking I would rather keep the up travel to a minimum to keep the vehicle more stable when climbing. Am I way off? It seems like it.
 
frankenyoter said:
OK.

I was thinking that something like that would be best in the unloaded position. If the shackle was more like 45 loaded it would allow more drop in the suspension. Then if the springs were being pulled down from the force of the other side, the shackle would be vertical. In my thinking I would rather keep the up travel to a minimum to keep the vehicle more stable when climbing. Am I way off? It seems like it.
Click to expand...

you're right. if you get 90° at full droop you're close to them kicking back and bending the main.

on the other hand, if you get too much angle on the loaded position, they'll flip up and lock. ask me how I know :rolleyes:
 
I don't think you are off. I think less than 70 degrees is probably OK when using springs that do not have a lot of arch. 45 degrees might be OK if relatively flat springs.
 
So this is where I am at. I didn't calculate the angle but it is probably 85 +/-. I assume that the springs will settle a little after I beat on 'em some.

I am using cruiser RUF and the pack I have under it now has to two AAL in it. The problem is now my U-bolts are too short to bolt up the axle and see what it looks like with weight on it. I don't want to purchase new u-bolts so something has to come out. A friend thinks I should keep the two AAL in it to provide lift and make it stiff. The AAL springs are thicker than stock springs and one AAL is shorter than the other.

If I remove the two shorter leaves on the base of the pack, how will that change the springs behavior? If I remove the smaller AAL I think it the U bolts will work too, but I will have less lift and more of a flat spring (I assume) after I set it down.

New Shackles.jpg
 
If you just remove the two small ones the pack will be thinner = flexier, flatter and more prone to bend and wearing out. AAL typically are stiffer hence the thickness. I would take the pack off and take measure it. then drop the two smalls and put the others on. measure it and see how it compares. more than likely you'll be fine with one AAL. is the above picture your truck on its on weight (ie-the resting shackle angle)?
 
Above picture has no weight on it. The springs are just hanging. Shackle hangers are just tacked. I was going to drop it down with tires and see what the shackles did and then adjust them. I am thinking hangers may need to be moved back some.

If I pull the second AAL I think the U-bolts will fit fine and this was my plan 'till someone came over to "help".
 
weighted shackle.jpg
This is weighted with the second AAL still in the pack. I will be removing it so this angle will increase some. What say ye all knowledgeable NC4x4 crowd?
 
I think that shackle angle looks good. If you remove one of the AAL's I think it will still look good.
 
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