Spring hanger height in relation to shackle

[PrerunnerRob]

I need to know the spring hanger height in relation to the shackle pivot mounting point measured from the ground up. I'm doing a solid axle swap on my 01 2wd silverado, and am using 73-88 leafs up front, and am tring to determine the correct height relation between the two.

[FormerMember]

Originally Posted by PrerunnerRob

I need to know the spring hanger height in relation to the shackle pivot mounting point measured from the ground up. I'm doing a solid axle swap on my 01 2wd silverado, and am using 73-88 leafs up front, and am tring to determine the correct height relation between the two.

I would say pay more attention to the caster angles on the front axle, then the shackle angle, then the pinion angle, then the height between the hanger and shackle... on average, the shackle angle is about 10 degrees past the bolt on most of the rigs I run.

Especially on a SAS: almost everything is custom there. Unless you feel like cutting the knuckles off of the front axle and turning them for proper caster.

To directly answer your questions, most SAS that I have seen run between a 4.5" shackle and a 7" shackle. That's a bolt center to bolt center measurement.

BTW, I have some brackets that may work for you. DIY4X does something similar to this for earlier gen trucks. I used one of their kits on my 72 C40 frame.

[PrerunnerRob]

Originally Posted by grendel

I would say pay more attention to the caster angles on the front axle, then the shackle angle, then the pinion angle, then the height between the hanger and shackle... on average, the shackle angle is about 10 degrees past the bolt on most of the rigs I run.

Especially on a SAS: almost everything is custom there. Unless you feel like cutting the knuckles off of the front axle and turning them for proper caster.

To directly answer your questions, most SAS that I have seen run between a 4.5" shackle and a 7" shackle. That's a bolt center to bolt center measurement.

BTW, I have some brackets that may work for you. DIY4X does something similar to this for earlier gen trucks. I used one of their kits on my 72 C40 frame.

Thanks for the reply, I dont think I stated my question well enough. I need to know the difference in distance to the ground from the fixed leaf spring pivot, in relation to the distance to the ground from the shackle frame pivot.
If you draw a horizontal line through the leaf spring pivot frame perch, what is the difference in height compared to the shackle pivot frame perch?
I'm just looking for a ball park number here, not anything written in stone.


Thanks in advance for the help!

[FormerMember]

Originally Posted by PrerunnerRob

Thanks for the reply, I dont think I stated my question well enough. I need to know the difference in distance to the ground from the fixed leaf spring pivot, in relation to the distance to the ground from the shackle frame pivot.
If you draw a horizontal line through the leaf spring pivot frame perch, what is the difference in height compared to the shackle pivot frame perch?
I'm just looking for a ball park number here, not anything written in stone.


Thanks in advance for the help!

Quite frankly, I am still trying to figure out your question?

I think that would vary based upon your frame kick up and out, lift of the spring itself and weight of the rig...

Whenever I've done an SAS (15+) I place the shackle hanger where ever it makes the best impact on shackle angle for the length of my shackles, after I factor my caster and pinion angles. I would also make my own shackles to be able to clear everything. One my last project (C40 frame) I bolted down the front of the springs, spaced the rear out so that my caster angles were right and my pinion angle wasn't too harsh and pierced the frame through where the top of my shackle would be at 10 degrees from the rear of the front spring, under weight. I had to use a 7" long shackle to clear the frame, but it works quite nicely.

Considering that you're doing a 01 Chevy with 73-81 leaves, not many people would have this measurement. Might have some answers in Pirate4x4.com 's Chevy section...