95 YJ shackle reverse

[drunkinpublik]

going to be doing a shackle reverse on the YJ and have a couple questions if anyone can help. I researched all the pros and cons so I have some idea what to expect. Curious how those that have done it like it. Makes sense to me to have the tire move away from a bump rather than into it. I drive a lot of washboard roads and think this will help. Not looking for a caddy ride just want to keep the beer in the can and off my lap tongue.gif

OK the questions:

1. I noticed in one of the better threads that an extended driveshaft is needed because the travel will be greater. Anyone know the proper way to measure the length and where I can find the shaft? Quadratec and the like have extended ones but they are to be used with a 3" or better lift system. I don't plan on lifting her at this time outside of what the srs will give.

2. When doing the reverse should I stay with the stock springs or should another set be used. My springs seem to be in pretty good shape, very stiff yet.

3. Noticed several different reversal systems out there, is one better than the other?

My preference at the moment is to pretty much leave it stock for this year and probably add a little larger tire with the increased lift if possible. Any help would be appreciated. Curious if it will help the ride or if I should just buy a dribble cup

[The Duke]

Have you already read this (http://bbb.quadratec.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=4;t=000604) ?

If not, you should.

[OhioYJ]

Actually I have a writeup that deals a little bit more with Shackle Reversal. (http://bbb.quadratec.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=4;t=000618)

As for your questions:

1. You don't necessarily need a longer driveshaft, you need one with greater travel in the slip yoke. In a shackle forward setup many times 1" - 1.5" of travel is plenty, whereas you might need 3"+ in a shackle reversal setup. Best thing to do the shackle reversal, then flex the Jeep out and measure the lengths of the driveshaft but extended and compressed, then have a local driveline shop, or any driveshaft shop make you a long travel driveshaft using your measurements. In some cases you may get away with using your stock driveshaft if you have it shortened some. Every Jeep is different though, so you'd be best to measure it.

2. You can run your stock springs, not a big deal.

3. Don't know really, I like the weld on stubby kits personally that gain you some approach angle and don't lift the Jeep.

[Wht 83 CJ7]

Something to think about,,like you said your tire moves AWAY from the object,,,when your trying to climb a rock or a ledge do you want your tire moving AWAY from the rock/ledge or do you want your tire pushing into it and up???

Shackle reverse is great for speed bumps and a little more approach angle but thats about it IMHO,,I dont know what mods you have now but seems to ME money is better spent in other areas,,Got lockers?? A lunch box will run about the same price
but to each his(or her) own

[drunkinpublik]

Thanks for all for the responses. Duke, I didn't see that article thanks, gives me a little more to think about. Ohio YJ's article was the one that I read in depth but now I am going to re think this. I personally don't mind the ride got kinda used to it but I have buddies that refuse to go because of it. I guess it must be a jeep thing smile.gif I wonder if just replacing the shackles will help. Maybe I'll try that first. I put all new shocks etc on but I have to admit, it is kinda a rough ride. Lockers, I like lockers might do that instead.

[The Duke]

I used to have a rough ride as well. Then I upgraded from a 10 year old Rubicon Express 4" lift to a Rough Country with Boomerang shackles.
The ride quality is a night and day differance. I felt every bump in the road and went out of my way to avoid several bad RR crossings because I would get some air between me and the seat even at 20 MPH.
With the RC lift, it feels like I'm driving a Cadilac.....well, sort of.

Any reason you don't want to lift it?

[Wht 83 CJ7]

greasable shackles do wonders for your ride quality also

[drunkinpublik]

The only reason I can't,(really want to), lift it this year is because I'm dumping a lotta jing into the house this summer, and I want a Harley...but a lift is maybe in this jeeps short term future. Most likely after reading the feedback and articles, (which I really appreciate), I'll wait for any mods outside of replacing the shackles with greasable ones, can't hurt. I only have a 2.5 in this and tried to kill the motor but only succeeded in doing the tranny and clutch mortal harm. So I have been debating wether just to upgrade to a newer model with coils or do this one justice. Pisser is I just bought everything I wanted for this one, steel half doors, bikini, stereo, whatever.

[Jeepskate]

Really depends upon your intended use of the vehicle. All of the points about the debateable value of it under certain off road conditions are valid, but may not mean much to you if your rig spends the vast majority of it's time on the street and you stick with more moderate wheeling. I have one rig with and one without SRS. I started out with one Jeep that I was building to be a daily driver & weekend warrior and it had a MORE SRS on it (no lift). I bought another Jeep project to replace that one that I wanted more, then a few months later bought another road-worthy Jeep to daily drive, and parted out the first project Jeep to help finance building the second project Jeep (kept parts that could be transferred over like the drivetrain) including the SRS since the new project would be an off road only Jeep. So, my off road only Jeep has the standard setup and when I revamped the daily driver I put a Full Traction bolt-on SRS (2" of lift) on it since it spends the majority of it's time on the road. I had driven a couple of SRS'd Jeeps in the past, so I knew what a difference it made for the ride & handling.

[drunkinpublik]

Well I made up what's left of my mind. I am going to do the SR on this vehicle and use it for work and town bombing around and pick up another pretty much all set up for trail riding. I wanted to ask how much if any fabricating I can expect to be doing. Thanks everyone for the fine input.

Lou

[kwrangln]

I'll try to throw up some tech for ya when I get back from dinner. Should be able to cover geometry, +/- of srs, etc.

[kwrangln]

OK, where to start? I guess you read my shackle write up that Duke posted a link to earlier, that should get the basics out of the way. On to the shackle reversal, this will dig a bit deeper into the mystery surrounding shackles.

To start with, a shackle reversal is not a cure all. Simply putting the shackles on the rear of the front springs does not automatically mean the ride will get better. It will not automatically mean that the axle will travel rearward when it encounters a bump. It will not automatically mean that you get an increased approach angle because the shackle is not hanging down there to hang up on stuff. It can accomplish all these things if it is applied and engineered correctly, but that goes far and beyond any bolt on or weld on "kit" that is out there now.

Lets take a look at the myth that placing the shackels on the rear of the front springs means you'll get a better ride because the axle will travel rearward when it encounters a bump. I like pictures, so check these out.

http://www.jeeptech.com/susp/elkcahs/nonr2s.jpg
http://www.jeeptech.com/susp/elkcahs/rev3s.jpg
http://www.jeeptech.com/susp/elkcahs/narch1s.jpg
http://www.jeeptech.com/susp/elkcahs/rarch2s.jpg

As you can see, with the stock jeep configuration, running flat springs (stock springs are close enough to call em flat), the axle already travels rearward when encountering a bump. A shackle reversal in this situation woule actually make the ride more harsh. Something to consider if you're planning a spring over axle conversion at some point since they will act the same way with flat springs. If you're planning on running lift springs then a shackle reversal will alter the axle movement so the ride will be smoother due to rearward axle movement. Clear as mud?

Now, on to approach angle. Lots of folks think that when they do a shackle reversal they can do away with the springs hanging down in the front and getting hung up on stuff. While this sounds good, it needs to be well thought out. If you simply raise the spring hanger in the front, you will throw your castor WAY out of wack, necessitating a cut and turn of the front axle housing to restore proper geometry. Thats all fine and good, but even if you correct the castor, the spring itself is not going to be parallel with the ground. Sure it can be run this way, but be prepared for crap storm you're opening up. Having the spring out of parallel with the ground means that as it flexes, the axle is moving even more forward and aft than a normal leaf spring. The steeper the angle, the more pronounced this effect. Which leads into driveshaft problems, in addition to crazy brake dive and increased axle wrap under power. If the driveshaft issue is not adressed correctly, it can mean the end of your transfer case as the driveshaft bottoms out and breaks the front output housing completely off the case. Correcting this problem gets a little expensive as most long travel drive shafts can run upwards of $400. Take another look at the pics I posted above and notice the angle of the springs between the shackle forward and reversed. When at rest with the shackle forward, the spring is parallel with the ground, with the shackle reversed the spring at rest is angled towards the front of the jeep. The proper way to go about this is to build the fixed spring mount the same distance below the frame as the stock shackle was. Now you're forced to fabricate a through the frame mount for the shackle to avoid extra lift from the setup. Maybe you need some more lift, but avoiding unnecessary lift is a good thing.

How can you make this work correctly? Its going to take a thourough understanding of the suspension geometry to start with, and alot of fabrication work. You can mount the front of the spring directly to the bottom of the frame, recess and mount the shackle above the frame rail at the rear of the spring, notch the frame and reinforce above the axle, and run a spring with some arch to it. This will give you improved approach angle, smooth ride, and maintain a low center of gravity with adequate wheel travel.

If any of this needs more explaining, post up and I'll see what I can do as this is all off the top of my head after a few adult beverages at dinner. Speaking of which I need another margarita, so I'm outa here.

graemlins/1welder.gif

[drunkinpublik]

KWRANGLIN, thanks for the excellent post and information. Definately gives me something to think about. I wish I had that kind of recall after consuming adult beverages. Well done smile.gif

My other concern is with the drop brackets mounted to the fixed end in front it will be putting a lot of stress on the very frontmost part of the frame rails.

will I need to add a lot of structure and crossbracing to keep the stiffness of the chassis, and do these kits address this?


Thanks

[Jeepskate]

Most of the kits come with front braces...I think MORE is the only one that doesn't..

This is mine with the Full-Traction kit and 2.5" lift springs:

http://www.jeepskate.net/images/7fsrs3.JPG

http://www.jeepskate.net/images/7fsrs1.JPG

http://www.jeepskate.net/images/cj7101004b.JPG

[drunkinpublik]

OK one more question and I guess we can call this post closed. Thanks Jeepskate nice to see pics to really understand what's going on.

For those that have done this, what kit did you use and if you had to do it again anything you'd do different?

Thanks again everybody, appears I posted on the correct board. Very informative. Thanks again

[kwrangln]

Jeepskate, ya mind talking about your setup a bit?

In this pic I used my mad MSPAINT skills to show stock spring placement vs spring placement with the SRS. The yellow lines are how force is going to be appied to the spring, with your current setup its going to force the axle rearward by a pretty large margin.
http://www.the-jersey-devil.com/photopost/data/500/101SRS1-med.jpg

Have you flexed this setup? Do you run into alot of body contact here?
http://www.the-jersey-devil.com/photopost/data/500/101SRS2-med.jpg
I know I did on my old YJ running stock springs SOA forward shackles and 35's. I couldnt imagine that you dont have some contact there that you may not have to worry about without the SRS.

To fix it a bit, I would raise the shackle mount so the spring sits flat. Like this.
http://www.the-jersey-devil.com/photopost/data/500/101SRS3-med.jpg
This would also lead to a better ride as the shackel will move with the suspension better when its sitting verticle or angled the opposite way yours is.

Not picking on ya, just looking for your first hand input vs my theorie. Since I havn't run a SRS, I'm relying on my basic understanding of suspension goemetry, and so far your setup goes against several of those basics. It may in fact ride alot better than stock, but I dont think you're getting all you can from that setup.

[Jeepskate]

No sweat, kwrangln. I have not flexed it out yet, but contact with the front fender is definitely on the watch list along with the slip on the driveshaft. There will definitely be a fair amount of rearward movement, which is the movement that you want in order to actually see any benefit out of the SRS on the street. I am still fiddling with the suspension (notice that the rear has some redonkulous lift shackles on it to level it out with the extra lift from the bolt-on SRS) and to that end have a set of 4.5" springs & normal shackles that'll be going on the rear and 2.5" YJ springs that'll be going up front which will nudge the shackle angle backward a tad more (keep in mind that in the last pic you marked with the shackle through the frame a la MORE, the suspension is basically unloaded...no body or engine...if you look at the pic of the assembled rig, the angle is much better and is just slightly rearward). I had the MORE setup on the project rig that preceeded my Scrambler:

http://www.jeepskate.net/images/frntsusp.jpg

Honestly, the ride and handling (save for the long rear shackles) on this thing is fantastic. I run greasable bushings, RS9000x's, tie rod flip, HD box mount & brace, Borgeson shaft, and old gen AGR Superbox II & pump and can cruise over a rough RR crossing with my pinky on the steering wheel without skipping a beat. Obviously I want to flex it out before I take it wheeling. This one is primarily for cruising on nice days and some mild wheeling while I'm building my Scrambler and to get my wife started driving on the trails.

[miikey]

ok so shackle reversal. done right. will get you better flex and a smoother ride?

a friend of mine was raving about how its the best thing you can do,
but then again, he'd have a few, and might not have been at the top of his game.

[Jeepskate]

No, it won't get you better flex...all you're doing is taking the same springs, flipping them around end-to-end and swapping the fixed mount and shackle, so the flex is the same. Th reason the driveshaft slip comes into it is because you're changing how the axle moves. Ride-wise, it'll help smooth out bumps in the road and washboard roads and eliminate much of the associated bump steer.