Longer Rear Shackles

[waskillywabbit]

I can already tell that I'm going to need a longer rear shackle and the install is less than a couple weeks old.  I've tried searching to get some insight but how do I go about measuring and determingin exactly how much longer a rear shackle I need?

[Brandon]

How long are your springs (along the arch) and how far is the distance between your spring mounts?

[waskillywabbit]

How long are your springs (along the arch) and how far is the distance between your spring mounts?

AP 5" extreme lift rear springs...moved front shackle on the rear up 6" and the rear one back 2"

[Brandon]

How long are your springs (along the arch) and how far is the distance between your spring mounts?

[Marketing]

What is your shackle angle now, shackle length eye to eye and how much do your want to lift the rear?

[MidgetMike]

Why don't you figure out how much lift you need multiply that by 2 and add it to your current shackle lengthassuming your shackle angle is between 30 and 50 degrees 

[waskillywabbit]

Here is my current angle...and yes, the tailpipe has to get moved...already taken care of.  Standard AP shackles and rear springs that came in the 5" extreme lift kit...

After several more weeks of settling, where do I measure to get the best idea of how much it needs to be raised?  I've always read that you get the distance you need and multiply by 2 and that is the length shackle you need...just curious...why multiple by 2 as opposed to some other number?

Thanks.

[FIREBALL]

Because you are only lifting(relocating) one end of the springs, the front stays in the same spot. So to get 1" in the middle, you have to move the rear down 2". It's just a rule of thumb, and not exact since most spring eyes aren't in the center, but it's close enough.
I would be careful about going too much more. How much lift do think your going to need? If you build your shackle too long you'll tend to swing back and forth on them, and may end up needing a panhard bar. Also the longer they are the more they hang down and make for rock catchers, and thier easier to bend.

[Brandon]

what u have looks good, I wouldn't touch it..

[waskillywabbit]

what u have looks good, I wouldn't touch it..

rear is lower in ride height already, but I'll see how everything settles...shackle angle is good, I just might have to raise the rear a bit later....thanks guys

[Brandon]

use blocks if ya need lift - I wouldn't touch the shackles