Reverse Shackle question

[BBP]

I have a 1983 CJ5. Will reverse shackes improve the off road ride enough to warrant the expense of having them installed?
Thanks for any replies...
Brent

[CaptainMorgan]

Absolutely...350cj5 has the Warrior reverse shackle on his CJ-5 and it rides MUCH better than mine. We do have different shocks and springs but I can tell it is much more than that, his front geometry is better as a result. His front flexes decent for a '5 also, I would attribute that to the S.R.

I wouldn't reccomend the Warrior though, look into getting a local shop to fab one that will be stonger and possibly around the same price.

[ob1jeeper]

On a leaf sprung suspension system, the shackles, (regardless of flexation or other "funky design") are SUPPOSED to be at an approx 90 degree angle in relation to the main leaf, AT STATIC LOAD... If they are not, the spring rate will go up, basically stiffening the ride...

SO... Unless the new "reverse shackles" have the pivots moved on the frame to CORRECT a deficiency of the effective angle of the shackle in relationship to the main leaf, a simple replacement of ANY shackle design with another shackle will do NOTHING to alter or improve the spring rate (thus the effective ride quality)...

Bottom line... NO... Shackles alone will do nothing to improve ride quality... :);)

[desertfabmotors]

Yes, a shackle reversal will improve the ride. In a nut shell the axle will move back with the bump instead of forward, so there are not 2 forces working against each other.
Back in the days any straight axle leaf sprung off-road race truck had a shackle reversal. Why? because it improved ride and performance:)

On a jeep you need to move the axle forward 1 - 2 inches when you do a reversal. If you don't the tire will hit the back fender well because the the axle moves back when the spring compresses.

[drroadie]

OB1jeeper makes a good point, and if he hadn't forgotten axel movement for, and aft, he would be right. The honest fact is, on road your jeep wont wander or dart as baddly, and off road, yes, the ride will be better. Do it, you will love it.

[CaptainMorgan]

I am actually amazed at the difference in Raul's and mine. It is like night and day, my front bounces up and down and his just seems to absorb the bumps better. It doesn't bounce up and down like mine because of the axle movement.

[ob1jeeper]

If you were inquiring about some sort of reverse shackle design, I stand by what I said... A shackle re-design, will for all intents do nothing to improve spring rate, or ride quality.

If you were instead inquiring about reversing positions of the shackle with the pivot for the front axle (IE: what Todd is referring to), where the shackle pivot is moved to the opposite end of the leaf, then I agree with Todd ... to a point...

That said, unless you are driving over some substantial obstacles at a fairly high rate of speed, (such as what Todd is referring to for the desert racers) I doubt that without other suspension changes to significantly reduce spring rate, that you would notice any incremental differences in ride quality for "normal" street driven applications. For "normal" uses, you should be able to obtain larger gains in ride quality improvement (total suspension rate reductions) by simply reducing tire pressures a couple psi and/or going to a tire with a larger tire volume, which is capable of absorbing more energy...

PS: the original and main purpose for the re-location of the shackle and the pivot on leaf sprung suspended desert racers was to put the forward cantilever section of the spring in tension (as it is on the rear axle), when striking a obstacle... This change provided the desired net result of reducing the numbers of springs main leafs, which were bent in columnar bending, which obviously resulted in the vehicle being out of competition as the result of a failed suspension component...

With the front cantilever portion of the springs main leaf in tension, it was/is SIGNIFICANTLY more difficult to damage the spring while running high speed whoops and washouts...

HTH...:);)

[desertfabmotors]

The reason why the ride is smoother with a shckle reversal and arched springs is the axle moves backwards under compression. This absorbs the bump alot more.
With stock set up with arched springs, when the spring is compressed the axle moves forward and hitting the bump going forward wants to push the axle back, make for a rougher ride. :)

This is to forces working against each other, which is why alot of times you will rip the solid mount off the frame or bend main leafs at the solid mount

[CaptainMorgan]

The reason why the ride is smoother with a shckle reversal and arched springs is the axle moves backwards under compression. The absorbs the bump alot more.
With stock set up with arched springs, when the spring is compressed the axle moves forward and hitting the bump going forward want to push the axle back, make for a rougher ride. :)

I knew you wuold say it better than me:cool:

[ob1jeeper]

Don't mean to belabor this... But it's not so much the arch of the spring that produces ride harshess from the longitudinal force vector (as opposed to vertical) inputs, but the angle of that suspension arm in relationship to horizontal...

INSTEAD, it is the angle of the control arm which produces this force vector... IF the rear pivot(s) of any control arm (leaf spring suspensions use the main leaf as the control arm) is significantly above the axle centerline or axle end pivot (or clamp in the case of a live/solid axle using semi-elliptic leaf springs [ie: a hotchkiss suspension]), such that the control arm is not essentially horizontal, then you do indeed end up with some amount of additive force vectors which provide additive vertical input loads at the frame end rear pivot... The steeper the angle of the control arm, the higher the vertical force component...

FWIW: this loading is no different than having the steering linkage not be horizontal, which as we know ... results in bump steer...

HTH...:);)

[CaptainMorgan]

All I know is how much of a difference it makes in two otherwise equal Jeeps. I will definitely do a S.R. when $$ permits.

[drroadie]

In the end all seem to be in agrement, weather they are trying to be or not. Do the SR. It will make a difference,,,,,, a noticeable difference.

[FrenchChili]

So reverse shackle is better for rock crawling and high speed? Or just one specific application?

[CaptainMorgan]

So reverse shackle is better for rock crawling and high speed? Or just one specific application?

I think it is better for both. It gives a better ride which is good all the time and if done properly gives you better articulation.

[FrenchChili]

I think it is better for both. It gives a better ride which is good all the time and if done properly gives you better articulation.

I can't remember what forum it was on but I read a reverse shackle could create more wheel hop. :confused::)

[CaptainMorgan]

That could be, I have never seen any front wheel hop from it...but it could happen under certain circumstances I suppose.