Topic: Shackle Angle ?

[don25]

What is a good rear shackle angle to have? 

[Brandon]

that question can't be answered alone..

It's all relative to the length and arch of your spring. Keep in mine if your spring is 100% FLAT your shackle length has to be greater than the distance from the mount to the shackle mount on the spring or it will over extend. Lotsa of angle will induce a bit more body roll etc.

So..

Tell me what your  doing and maybe I can give a better answer

My angle is about 45 degrees but like I said - depends on your springs..

[don25 [OP]]

what mount are you talking about, the shackle mount on the frame? wouldn't the length of the shackle and the distance from the frame mount to the spring mount be the same ? I have five inch longer than stock spings, arched for 5" of lift.

[Brandon]

not if they are along the same plane..  If so you have a 0" shackle

I am talking about IF your spring is 100% flat (if there is arch measure along the arch to find the "flat" length)

[FIREBALL]

Here's some other ways of thinking about it. If you have quite a bit of arch, like it sounds like you do, and your shackle is straight up and down, when your axle trysto drop the shackle will move forward. It won't be able to move very far forward before it becomes inline with the length of the spring, and when it does it won't droop anymore.
The spring needs to be able to change length from tip to tip, the shackle allows that length change.
If your angle is too steep, when the spring compresses/tucks it's trying to get longer and the shackle is already nearly at it's furthest distance it will prevent the spring from elongating to it's full potential.
Hope that makes sense.

[don25 [OP]]

Ok that makes sense, thanks for the help. My shackle angle is around 45 degrees.