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Shackle reversals gained a lot of popularity back in the day because they improved the on-road behavior of lifted rigs. Generally, you introduce several degrees of caster when moving the shackle to the rear of the spring. This can reduce wander, death wobble and other undesirable handling characteristics. I've always felt the "improved ride" people talk about was actually "improved handling."
 

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Good information to THINK about. But: To me, which end is attached to the solid mount depends on whether spring over or spring under, and the type of wheeling you are going to do. I feel that the spring should always pull on the solid mount under accel...or upon hitting an obstacle at speed.

A high speed 4x4 will want the solid mount forward so terrain hits that want to move the axle back will be resisted positively by the front solid mount. There are little/less forces trying to turn the leaf spring into an S or W profile.

A 4x4 used mostly to resist the torque of accel should have the solid mount where that torque is being resisted by the solid mount. The rotation of the axle tube from axle shaft/wheel torque should be resisted by pulling on the solid mount. So depending on whether you are running spring over or under will determine where the solid mount should be. It seems like you do not want to push against a solid mount causing the spring to curve more and want to "buck back". (But that does/can happen under braking)

A thicker spring pack will resist the leaf turning into a S or W. Which seems why A "Deaaver" spring can be soft in ride but also strong in resisting storing energy on accel or braking when going into a S or W profile.

Thoughts.

IN the fast desert, the solid mounts should be forward on both the front and rear axles...whether spring over or under. (Spring over seems best to also resist axle/wheel torque on acceleration)

Crawlers, or towers, should mount the solid end to resist the wheel/axle torque. So in spring under, if the wheel is going clockwise under accel the axle wants to rotate counter clockwise so the solid mount should be to the rear. If the spring is over the axle, then the solid mount would be in the front.

I am sure there are other thoughts on this. Especially if you want the axle to rotate into an obstacle(rock) for traction or recede from it. Probably some axle steer considerations, etc.

Pushing against a solid mount is probably the #1 reason springs bend toward that eye. And why the "solution" was/is to wrap the two long leafs together. (Military wrap)


P.S. Good information of shackle length. Common today is moving the shackel pivot from under the frame to inside (frenched) or on top of the frame. This allows for more horizontal shackle movement without being to low to the ground, or lifting the ride height too much. All a system to think about.

And why the topic used to be disputed often....... before links.
 
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