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what is a reverse shackle conversion?

24K views 16 replies 13 participants last post by  XJ2CJ 
#1 ·
Hi all,

I'm checking out a Scrambler to buy. The owner said it has a reverse shackle conversion on it. I have no idea what this is is :confused:. A little help here!
 
#2 ·
shackle reversal

A shackle reversal is where the front shackles are moved to the frame and the front spring mounts are stationary. My 86' CJ7 has a shackle reversal and it rides much better and has a lot less to get hung up on now. I really like it. Probably one of my better suspension mods. I have it Paired up with some Rough Country Boomerang Shackles and it has been great.

Behind Drivers side Front
 
#7 ·
A shackle reversal is where the front shackles are moved to the frame and the front spring mounts are stationary. My 86' CJ7 has a shackle reversal and it rides much better and has a lot less to get hung up on now. I really like it. Probably one of my better suspension mods. I have it Paired up with some Rough Country Boomerang Shackles and it has been great.

Behind Drivers side Front
Your shackles are upside down, my friend. The way you have them is for their original intention...clearing the rear crossmember on the rear of YJ's. Used anywhere else, they function as anti-kickback shackles, but you have to flip them opposite of the way you have them so that the center brace hits the frame before the spring can invert. :thumbsup:
 
#4 ·
The fixed point moves from the back of the leafspring to the front. This way when you hit a bump, the tire/axle movement is up and back, instead of forward and up like the normal set up.
 
#5 ·
For the OP. The motion change to up and back is an important consideration. I've considered this mod but I'd have to have different front fenders. My tires hit the inner fender as it is now.
 
#6 ·
To add another note on the direction the axles travel. On the trails when you approach a ledge or rock the wheels move up and back away from the obstacle obsorbing the force and giving you less traction. The normal setup pushes forwards and down towards the obstacle putting more force and more traction to your tires.

On the road, the vehicle tracks better and the ride is smoother for the same reason described above, but also nosedives like crazy on medium to heavy braking. I reversed the shackle reversal the previous owner did on my jeep.
 
#9 · (Edited)
so, in addition to the reverse shackle conversion on the CJ8 I'm looking at; I need to make sure other mods were done to accommodate the change....ie a drive shaft modification.....is this correct?

if it is correct, what kind of damage could be (or can be) done if additional steps weren't taken?

According to wrangl3r: From what I'm reading here, it sounds like a reverse shackle conversion is more street friendly (minus the front end dipping down with heavy breaking), and is not preferable to climbing over obstacles (because the axels and therefore the tires move up & away from what you're trying to climb over AND the front end dives down). So, one reason a reverse shackle is done is to make your Jeep more street friendly.

These guys ( http://www.rocky-road.com/truth.html ) say "no" to reverse shackles on a short wheel base vehicle. Do you all think it's OK for the CJ8?... being the wheelbase is a little longer. AND keeping in mind that while it will be driven on the sand quite a bit, is it safe for highway use?

I'm sorry if it seems like I'm beating this issue to death. I just have no experience with the subject. Thanks again for all of your help!!
 
#10 ·
Actually, reversed front shackles came from the factory on the M38A1's. I run one of these frames and found the ride to be smoother and it takes sharp obstacles better that the original shackle configuration. While I can't testify to any high speed antics due to my somewhat slow driving habits behind the wheel, I can say I have observed no ill handling effects. In fact, steering is crisper due to the lateral force of the steering being taken up by the fixed hanger up front instead of the shackle which wants to flex more.
 
#12 ·
Keep in mind that anything that "gives" you positive caster by re-orienting the axle housing is also going to make your pinion angle worse. What you're saying only becomes true if the SRS was engineered to have the leaf's shackle eye in a lower vertical position than that of the leaf's spring hanger eye, tilting the axle housing back and pointing the pinion towards the ground. If you look as the design of your CJ's frame (stock), it goes up forward of the spring hanger. That distance is taken up by the shackle in the stock configuration and the leaf sits (relatively) level in stock form. SRS's frequently end up with spring hanger mounts that hang down a lot in order to keep the leaf relatively level, use a reasonable shackle length, and not screw up the axle's caster. A lot of times this results in lifting the front end further.

It should also be noted that the movement of the axle/tire and engagement of obstacles as described only applies when your leafs have arch. An arched SRS leaf will move the axle/tire rearward. In the event that you are running flat SRS'd leafs (stock YJ leafs), your axle & tire will be brought forward into the obstacle regardless of compression or droop, as that kind of leaf's leaf's eye-to-eye distance will always decrease when it bends.
 
#13 ·
I've got a SRS on my CJ-7 and it rides much better, even with the 4" lift. I had to get a slightly longer driveshaft (I used an extra rear shaft I had for a T150/D20). Haven't noticed any bad effects on driving, even up to about 90 mph.
 
#16 ·
I was looking for many peoples experiences and thoughts on the SRS before I ordered my frame with it. Most were pros, not many cons.

As for the handling - I had mine up to 75 or so a few times, Handles fine. The nose dive issue, I've noticed it a little bit, but it isn't that bad. Most vehicles do it on hard stops.. and it is still controlled, not like if it would nose dive and just dart around or something. And it does seem to be a lot smoother over rough roads.

The worst that could happen if the drive shafts weren't fit properly? Punch the front of the t-case out on a full compression.

I haven't had mine on any trail rides yet, so that part I cannot comment on. I had a couple people say about how it helps the front end 'hop' up over an obstacle like a log, but I couldn't tell you from my experience.
 
#17 ·
I know this is an old thread, but in the spirit of discussion one thing I've noticed on YJ's without the reversal is bent front springs just in front of the rear spring mount. My thought is that the spring acts like a control arm in positioning the axle and when a large bump is hit at high speed the axle is pushed back into the spring and mount and bends the spring. It the shackles had been reversed the spring would have been in tension from at the front and the rear would be able move. In the case of a flat spring (stock yj) the spring being in tension at the front is better than the stock setup with the rear being in compression (which leads to buckled/bent springs). Just a guess. Could be wrong.
 
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