Proper shackle angle

[brider]

I searched the forum, and came up with lot's of suspension discussion regarding the effect of the length of shackles, etc, but only a few on the proper "loaded" angle.

I found a convincing argument for a 45 deg from vertical loaded angle for optimum shackle positioning.

Is this a good rule of thumb? Seems to make sense to me, I want to know what I'm talking about when I order new springs.

I would guess that you need enough angle to prevent shackle-reversal (slight angle away from axle when wheel is hanging free), and not too much so that the shackle swings up against the frame before spring reaches bump-stop.

Am I correct?

 

[JohnnyC]

i would say 45 deg is a bit much...my skyjackers bottom out to the shackle hanger and they are at about 45 deg...i would say the stock angle would be best...see pic

my 2c....i am probably wrong...but my opinion is 100% correct

 

[Mace]

The angle is dependant on the springs used.

With lift springs it is possible to not be able to use the 45* angle.

 

[Brainz]

Yes the springs have a lot to do with it...but you can move the hangers as well to get a better angle. I think the consensus is that you want it past vertical or more...

 

[brider]

Yeah, on second thought, 45 deg seems a bit much.

 

['74 UA FJ]

45º would be fine when the spring is flat, I would think.

 

[Pin_Head]

There is no single angle that is best for all springs.

The overarching (pun intended) concern is that the length and angle of the shackle accomodate the full range of the spring on compression and droop. If the shackle angle is too extreme or it is too short, the spring may hit the frame on compression. If it is too verticle it may reverse. Once you know the shape of your spring, you can calculate the shackle angle and length that will be optimal for articulation.

The idea that 45 degrees provides for significantly better ride quality is a net rumor. For a flat spring, a 45 degree shackle actually increases the effective spring rate, but you need it for the spring to droop for full articulation.

 

[Jakes40]

this is what I have now but I'm going to move the mount forward for more toword 60 deg angle. just my preferance

 

[rockcod]

I am relocating my rear upper shackle mount to match the front shackle angle.

 

[watrob]

I am relocating my rear upper shackle mount to match the front shackle angle.

The shackle angle on your rear is not bad. If you have only just put those springs in then give them time to settle. Mine started out about where yours are and in a month they nmoved about 10deg.

Also if you load your FJ up with a few bags etc your springs will work well.

How long have you had the springs in for?

 

[rockcod]

Since 1972

The shackle angle on your rear is not bad. If you have only just put those springs in then give them time to settle. Mine started out about where yours are and in a month they nmoved about 10deg.

Also if you load your FJ up with a few bags etc your springs will work well.

How long have you had the springs in for?

 

[watrob]

Mine were 1974 originally but were RS, had to be replaced. Yours look like they have held up well?Have you pulled them down and rebuilt them at any time?

Robert

PS. Have you done a SOA?

 

[rockcod]

SOA just completed, disassembled the front packs,cleaned, repainted, re-drilled and flipped, new center pins and bushings, the rears I replaced the bushings. Sorry to hi-jack.

 

[ColoCruiserJeff]

I know I'm reviving an old thread here....but I'm running into insanely rough ride due to shackle angles - I have a 90deg to the road shackle angle.

How difficult was it to relocate your shackle mounts??

Any thoughts?

 

[zayac]

I am also curious what to do with vertical shackles. Mine are also 90 deg from the road, front and rear, with new 4'lift springs, no SOA.

Is relocation of hangars neccesary, or is there another way, like a different shackle design?

 

[Splangy]

I am relocating my rear upper shackle mount to match the front shackle angle.

I would spend the money on bigger tires!

 

[Fast Eddy]

I would spend the money on bigger tires!

...if you have any left after two and a half years.

 

[Pin_Head]

I'm running into insanely rough ride due to shackle angles - I have a 90deg to the road shackle angle.

Any thoughts?

The rough ride isn't due to the shackle angle.

It has to do with a mismatch between the spring rate and the weight of the truck.

 

[Ziffdaddy]

The rough ride isn't due to the shackle angle.

It has to do with a mismatch between the spring rate and the weight of the truck.

ahhh, thank you. I'm so tired of hearing about a rough ride from shackle angles...

 

[fjjonnie]

ahhh, thank you. I'm so tired of hearing about a rough ride from shackle angles...

x2!!!!