shackles (leaf springs)

[N-Smooth]

okay i wanted to start a post about this.
when you lengthen a shackle, divide the amount you lengthened it by 2 and that is how much lift you gain roughly... correct? so if you make your shackles 2 inches longer you get one inch of lift, this is because you are only lifting one side of the leaf spring.
okay so here is the question, what affect does moving the shackle mount forward have on a leaf spring? this is rear application by the way. i am saying this because i am going to be mounting my leafs on my toyota frame that i got and i am going to shoot for about a 45 degree angle... which i believe is most recommended. so if i move the shackle mount an inch forward from stock should i lengthen the shackle one extra inch or two??? i am betting it is just a guessing game and i will just tack on the mounts and see if that is what i want, and then if it isn't i can break the welds and remount.

-nate

 

[crimsonride]

Do this. If it matters that much to you. Take the length of the shackle, square it and detract the length from top to bottom of the shackle on a 45 degree andgle squared. Take the square root of that and that's the height you'll get plus or minus 1/4" due to the "elongating stress" (that I'm not sure really exists, just made that part up)

Edit: Man, I didn't even realize how stupid that was till I reread it.

 

[crimsonride]

Wait a second. That was stupid. Just measure how hight the shackle is on a 45 degree angle, devide that by half, that's what you'll get.

See, math's not that important.

 

[Caleb]

what you'll need ot do is the pathagorean therom (I think thats what Chris just described) basically a2+b2=c2 (2s=squared) and then just keep everything equaling the same when you move it...but IMHO, I think you are making it a bigger deal than you deal to...just measure mock up and if you think you need to move it or whatever do so...not hard and only takes a little bit of time...

 

[crimsonride]

yeah, see that's what I first came up with when I figured that when you do that, you need at least the length of one of the short legs in the triangle. Then I realized that that was the heigth of the lift he was getting from the shackle. minus the length of the old shackle and divided by two of course.
Does that make any sense?

This is what I do. "hmmm, two inches is what it gets normally, so we'll get, oh...maybe one, one and a half, yeah, that sounds about right"

 

[Klif01]

Sheesh, screw the math part. I hate math. I am imagining this, and I hope I am understanding what you are asking. If you kept the same shackle and moved the mounts forward Its seems to me that this would lower the vehicle. On my chevy swap I had just the springs hanging with the front mounts tacked where I thought they would go, Then, unweighted I had the shackle like just a few degrees off verticle. Unweighted it was almost perfect 45*. Good luck






Yes, its a guessing game...!!!!1

 

[N-Smooth]

wow i didn't think pythag would be involved in this, that is weird but it make sense i guess. it shouldn't be that hard really.

 

[grinch]

There is a neat math equasion for figuring out lengths of offsets for 45 degree angles.... It only works for 45s thoagh.....
Take your shackle hole and frame mount hole and draw or pretend draw paralell lines to the ground take a measurment between the 2... lets say you want 3 inches, times that by 1.414 and thats your new bolt hole to bolt hole measurment (4.242 or 4 1/4 inches)...
If any of that rambling makes any sence lol.....

 

[N-Smooth]

If any of that rambling makes any sence lol.....

kinda... if you want to go into it more that would be good.

what do you mean by shackle hole? the one on the leaf or to the frame?
and lines parallel to the ground right?

 

[N-Smooth]

also, what do you guys think of using re superflex joints in shackles? you would have to configure it like this: run tabs down from the frame to go around the joint and then have the joint welded to some tube that has tabs welded onto it that will go around the leaf spring bushings.

i know that somebody makes shackle bushings that twist like that, but this idea is definitely cooler!

 

[crimsonride]

also, what do you guys think of using re superflex joints in shackles? you would have to configure it like this: run tabs down from the frame to go around the joint and then have the joint welded to some tube that has tabs welded onto it that will go around the leaf spring bushings.

i know that somebody makes shackle bushings that twist like that, but this idea is definitely cooler!

I think a buggy spring setup like that would be pretty cool. Easier to do too.

 

[grinch]

Sounds like alot of work for unusable flex.... Just like most buggy spring set ups... looks good on ramps but unloads in the wrong places, causes axle hop, ect...(unless you build traction bars and so forth). By the time you get there you mine as well have built a coil/link set up.
By the shackle holes I mean where the shackles bolt through the frame and the spring.... and yes paralell to the ground.. You take the distance between the two on the paralell lines times that by the 1.414 and that will tell you how long the shackle should be between the two. So if its 3 inches and you want it to sit an inch taller you take 5 inches(rember it has to be double the lift you want) times that by 1.414 and that is the new distance you want between where your shackles bolt to the frame and leaf spring.