Minimum Shackle lengths?


Well-known member
Is there a minimum shackle length determined by the number of leafs in a leaf spring when the shackle is bolted to the stock frame holes?

Is there a minimum shackle length determined by the length of the spring when the shackle is bolted to the stock frame holes?

Is the length of the shackle determined by the shackle angle when bolted to the stock frame hole and leaf spring?

Excuse me for reading into it too much, I need to lower the shackle length to not install an SYE and Cardon and...
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Club Member
Minimum shackle length would actually be based on travel of the main spring. Basically it needs to be long enough to handle an arc between the shortest (droop) and longest (compressed) lengths without inversing itself. If you actually want to be specific, you could pull the leaf spring apart and use just the main spring, cycle the suspension with a hoist/forklift/whatever, and see the travel. I've seen exactly 1 build ever go to that level of detail in the hundreds/thousands I've read.

In your case, given that you are running a YJ with lift springs, I'd ask the manufacturer of the lift springs, or look at typical YJ shackle lengths. The biggest concern, in my eyes, is droop and having the shackle flip backwards. On compression, if you find it hits, throw in some bump stops if it's an issue. And while you are looking at travel, make sure you aren't bottoming out your shocks, or using them as a limit strap, as you'll rip off the mounts. Ask me how I know :(


Well-known member
Thanks again.
Yes, shackle inversing or flipping is one reason.
The shock travel and not bottoming out.
Bump stops already on top of both axles.
I will make shackles in 3 inch lengths for starters and see how that looks at the shocks, flip tendencies and bump stop travel.
Just trying to limit how far the driveshaft will slide out from the TC and raise the pan to the frame, remove spacers. Having 4 leafs plus the helper per spring set I don't feel a lot of articulation is going on and the body has a 1 inch pucks.

The older I get the more I realize how little I know in the fast paced metropolis.