shackle questionnnn

okay so this ain't xj related but it's leaf-spring related and our xj's have those so here:

my buddy has a 4runner with like 4" lift leaf springs in the rear, with a load going over bumps or off-road or just hitting big bumps hard the rear suspension drops, as in the shackle swings back towards the bumper and flattens the leaf spring, would fabbing up a 2-3" longer shackle cure this or just make it worse by swinging back easier?

Yes, the shackles need to be longer. About 2" should work.

alright thanks a lot bud, not sure about shackle length to lift ratios but how much lift should we expect with a longer shackle? trying not to get any more lift.

You will gain some lift but the shackle won't over extend anymore. You could move the frame mount rearward also. You want the shackle to swing back, but not too far.

The general rule is you see 1/2 the amount of lift to shackle length, since you are only propping up one side of a two-ended spring. So a three inch shackle is good for around and inch and a half of lift, give or take .

Skwerly said:

The general rule is you see 1/2 the amount of lift to shackle length, since you are only propping up one side of a two-ended spring. So a three inch shackle is good for around and inch and a half of lift, give or take .

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Its less if the shackle is angled properly. Depending on the spring arch the shackle should have about 30 to 45 degrees of angle. A flat spring would be at 45 and a higher arched spring at 30.