Shackle lifts... are they a bad idea?

Shackle lifts... are they a bad idea?
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rustybrownCJ

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Frisco, Colorado
Vehicle(s)
1980 Jeep CJ-7 stock amc 304
I have a 1980 Jeep CJ7 with stock AMC20 axles and a 4" leaf spring lift and 33 inch tires. I need to replace my stock shackles so I figure why not add a little lift. When I got my box of new daystar 2 1/4" lift shackles I was blown away at how much bigger they were than my originals. Then I got to thinking I could be stretching my drive shafts, brake cables, etc. and don't really know if lifting that much is ok for my set up. Any input would help. Thanks
 
I do not like shackle lifts had a 2'' and will never do it again.
 
Forget the longer shackles, enjoy the spring lift, 4" should clear 33's, are you having clearance issues?
 
:agree: that big a shackle is going to throw your caster off, and give you some really bad steering problems.
 
I agree with above, thats a TON of shackle lift.

I added one inch to the fronts on mine and noticed no adverse affects. Any more and I'd think the shackles look too long also.
 
shackels arnt a good thing unless its solely a budget farm toy where it wouldnt matter much IMO
 
I wouldn't go more than 3/4 inch lift from a shackle.

(1 1/2 inch taller shackle) And I would only do that with lift YJ springs already installed.

Caster issues aside, (and it's a BIG deal, others have and will chime in on this point.), shackle geometry must be maintained.

With a YJ spring conversion, using an inch longer (4 in. YJ vs CJ 3 in.) stock YJ shackle, plus the lift in the difference of arch CJ vs. YJ in stock form gives you a safe lift increase above what the spring alone gives you.

Different kits and homebrew solutions vary a little in hanger placement, but the proper shackle angle is almost always maintained with this minor shackle lengthening.

I believe that using the 3 to 4 inch difference as a baseline 25% , then going from 4 to 5 1/2 inch (37.5%) (many popular greaseable shackles are this length) on YJ springs seems acceptable. It definitely seems the limit, from what I've seen.

Eight inch shackles on CJ springs are nearly triple the length of stock.

Six inchers are Double stock length( 200 %)

Translating that math into geometry terms is a little tricky, but I hope you see where I'm going with this.

I went to a Jeep event on "go topless day" this sat, and it's scary how many CJ and YJ owners have dangerously tall shackles.
 
I have no issues with longer than stock shackles but there are limitations and things to overcome. First let me say that I've ran shackles for 27+ years, so I have a bit of experience with them.
A stock CJ shackle is 3" bolt to bolt and the cross bolts are welded 90* to the one side plate. Any increase beyond that will give you half the added length in lift (your only lifting one side of the spring and the axle is located pretty close to center). Shackles do 2 things, they allow vertical flexing of the spring, and therefore axles, and they keep the axles lined up with the frame (on a CJ). When you lengthen the shackles you also increase the leverage on the frame mount, so a beefier shackle mount is needed such as Slickrock's or CrabTree Tools offer. Shackle side plate racking also gets increased so center blocks welded between the sides is also needed to keep these plates parallel. And it goes without saying that the metal itself needs some beef to it, like 3/8".

There is a limit to length too where side forces via leverage can overcome even these improvements to other components. I've never seen an aftermarket set for Jeeps offer for more than 2 1/2", most have up to a 2" set. Now obviously use will come into play also. You wouldn't want a set of long shackles on a rig that does a lot of sidehill and off camber stuff, nor would you want them used in combo with high lift leaf springs like 4"+ ones because these would multiply the problems.

Caster isn't always an issue and it isn't always due to the shackles. It's more of a "which component was there first" thing to determine blame. I had a set of ConFer 5 1/2" (bolt to bolt) shackles and stock springs w/add-a-leafs on mine for years with no steering issues but it wasn't till I removed the springs & add-a-leafs and put on a set of 2 1/2" springs that I now experienced problems. That in total gave me about 3 3/4" of lift. So I could also make the claim that 2 1/2" springs gave me caster / steering problems.

So to address your original comment Rusty. If I had a 4" spring lift already, the only thing I would do is to maybe add a set of beefier shackles but of stock size (3"b2b) or maybe 1/2" longer (4"b2b) at the most. A 4" lift should be good for 33" tires. Maybe you could replace those worn out (assuming) body mounts with a set of poly Daystars that have 1" of additional lift built into them. This is the route I'm taking on my rebuild. These won't effect your driveshafts or cable lengths like suspension components would, but a longer rear brakeline (center) might already be needed with a 4" lift alone.

Shackles seem to always get a bad rap even when it's not deserved.
 
I disagree a little with what you said, PaRenegade.

So I could also make the claim that 2 1/2" springs gave me caster / steering problems.
Click to expand...
Lift springs usually, if not always, don't effect caster. Shackles do. This is my take.

Lift springs almost always account for the center pin location in relation to the stock hanger locations.

Add two or four or six to each side, Such as in lift springs, and the angle remains exactly the same. Assuming stock shackles are used. Assuming the springs aren't loaded above design AND they are not worn out/ sagging.

Wander is a steering geometry issue, so lift springs can be blamed on that, and pretty much everything else of you said I agree with. Especially about stock mounts. :chug:
 
I guess my point was, "which came first, the chicken or the egg". The shackles themselves don't necessarily create problems, but when combined with other components problems can appear. Yes, shackles will almost always change caster, but a slight change isn't always noticeable until it's a couple of degrees out of spec.
And not all springs are created equal, in regards to quality control of rates and dimensions. I suspect thats why I didn't need degree shims till I added new springs. If the only dimension that changed was the vertical distance from spring eyes to spring seat, theoretically the caster would have remained the same, all else being equal.
But even weight distribution could come into play when changing springs, and therefore spring rates, since the amount of flex could change. This is why OME springs are offered in light, medium, and heavy rates, because you can't have a "one size fits all" spring.

There's a lot of variables that could come into play and each situation can differ. I guess that's why it's so appropriately called "geometry"!
 
I just bought a 86 CJ7 with 5" shackle lift and I hate it.....how easy are these to undo and what all will be effected?.....different shocks?..
 
What do you mean by 5"? 5" beyond stock, 5" of lift, or 5" bolt to bolt? There are many myths out there about shackles.
 
Not a big fan of longer shackles for the reasons stated, plus they create just one more clearance issue when it comes to approach and departure.

I do however recomomend using YJ shackles. They are stamped steel and are much stronger then CJ flat steel shackles. Also they provide ½" more lift...to keep it sane. CJ shackles are 3 inches eye to eye, YJ shackles are 4 inches eye to eye.
 
They are both stamped steel and I wouldn't recommend either. The wrangler ones just have a deeper stamp. But I also wouldn't recommend all aftermarket ones either. Sturdy sides that won't bend and a means to keep the sides always parallel is what you want. Any flex is the job of the bushings.
 
stljeep said:
it's 5" bolt to bolt.
Click to expand...
That means they are 1" lift.
Just buy new shackles if you want to change them.
I doubt if you will need new shocks, but who knows what the PO might have on there.
 
I agree, 1" of shackle lift isn't too bad and your ride could be suffering from several reasons. Is there any spring lift in addition to the longer shackles? Are they old springs that maybe sag? Are your body mounts cracked and worn out? And maybe the shocks are just shot too. Maybe the shackle bolts are over tightened.
Pics would help and a description of how it rides, what makes you "hate" it.
 
no springs.....just shackles and shocks.
Bare with me by the way, this is all new to me...I remeasured and the front shackles are 8" long with 3 bolts....6 1/2" from center of top bolt to center of bottom (or third) bolt.
The front rocks up and down pretty bad....really think its just the shocks?
 
I can't post pics for some reason....can't find the option on this forum...I looked a lot but can't find it.
 
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