Moving Center Pin??

[OhioYJ]

So I'm having another crazy thought, how about just moving the center pin on my current leaf springs to gain wheelbase? Can I just move the center pin 1"-2" forward and back, and lengthen the driveshafts?

[OhioYJ]

Or how about re-drilling holes in the spring perches? If I remember right, my spring perches have three sets of holes anyways?

Wouldn't moving the spring back on the perch, also help fight wrap to some degree, by making the front perch a little longer?

[olivesta500]

Wouldn't moving the spring back on the perch, also help fight wrap to some degree, by making the front perch a little longer? maybe i misunderstood this but for the rear axle if you moved the spring back on the perch that would be moving the axle forward and losing some wheelbase, unless your talking about the front axle.

about moving the center pin back, there might be some side effects like you could lose some articulation if you moved the pin too far back. not too sure if the gain in wheelbase would make up for the loss of flex or wear on the springs from being stressed in a different place than theyre used to IMO HTH

[HotRod YJ]

I wouldn't try to redrill and move the centerpin in the actual spring, but redrilling the perch and U-bolt plate is an easy way to gain 1-2" depending on how much room you have. That's exactly what I did with my front axle. I redrilled 2" off center to move the axle 2" forward without changing or moving the springs. Works just fine. I actually didn't have room to safely go the full 2" so I welded a 1/4" plate to the top of the perch with the new hole drilled in this plate. 1/4" isn't enough to have any effect like a lift block would, and this gave me the extra beef I needed around the new hole at 2" from center to make it a safe modification. I was making new U-bolt plates anyway from 1/2" plate, so I drilled the centerpin hole where I needed it to be, 2" off center.

[OhioYJ]

My spring perches have three holes in them,

http://www.rubiconexpress.com/images/tnRE1935.jpg

Looking at things, 2" would be really close (I dont' think it would clear my pitman arm or my gas tank), my rough guess is that the holes in the perch are 1" apart, so I'm thinking if I try the farther hole in the perches front and rear, I could pick up almost 2" of wheelbase total, and imrpove my approach/departure angles. The front shaft I think will be long enough, the rear needs to be longer anyways.

I would however like to ditch that CV shaft, just to simplify trail repairs.

http://i6.photobucket.com/albums/y249/mr5oh/driveshaft45.jpg

I don't think my angles look to bad right now, plus it would be a little longer yet from moving the axle. Anyone think that CV shaft is completely necessary?

[kwrangln]

Originally posted by OhioYJ:
I would however like to ditch that CV shaft, just to simplify trail repairs.

http://i6.photobucket.com/albums/y249/mr5oh/driveshaft45.jpg

I don't think my angles look to bad right now, plus it would be a little longer yet from moving the axle. Anyone think that CV shaft is completely necessary? It is unless you plan on dropping your pinion angle about 4" so the output on the Tcase and pinion yoke are parallel. Once you do that you'll probably be pushing the angles enough that you bottom the yokes blowing up U-joints. I ran a standard shaft in the rear of my black jeep and with the rear suspension fully drooped it bound the yokes. That wasnt with lift springs, just the SOA.

[cooncan]

I don't mean to hijack your thread OhioYJ, but could I get a full pic of your wrap bar. I need to make one for mine and would like to see how you made the front attatchment. Thanks!

[OhioYJ]

but could I get a full pic of your wrap bar.Sure, I just took these in the dark, but I think you can figure it out.

I have a body lift on my Jeep so I have a 2"x2" sqaure tube welded to the top of my frame to attach that wrap bar to.

http://i6.photobucket.com/albums/y249/mr5oh/wrapbar1.jpg

This thing goes on the passenger side, do yourself a favor, move your exhaust. Mine is on the wrong side and it torque steers bad, I get on the gas and it wants to make a left turn, get off and it wants to make a right turn, wrap bars go on the passenger side. (One of these days I'll move mine) Second thing other people say is that where my shackle is point down, it should actually point up (the wrap bar should pull up rather than push up), this I don't necessarily agree with, I think its the same push or pull it doesn't matter in my opinion.

http://i6.photobucket.com/albums/y249/mr5oh/wrapbar2.jpg

Then just some plate steel to make a mount to the axle. It works, it just needs to be move to the passenger side to get rid of the quirks.

[olivesta500]

mike, sorry to hijack the thread even further but could you explain why moving the wrap bar to the passenger side would get rid of the torque steer. maybe is it because the direction the driveshaft rotates? it doesnt really make sense to me. i understand about the push vs. pull on the shackle on the front of the bar and in my opinion i would think it would make more sense to be mounted in the "pull" configuration. anyway im just confused why the passenger or drivers side makes a difference. im trying to understand this so when i {darth vadar voice} come to the dark side {/darth vadar voice} ill be more prepared. thanks

[cooncan]

Good pics, great ideas! Thanks!

[kwrangln]

Originally posted by olivesta500:
mike, sorry to hijack the thread even further but could you explain why moving the wrap bar to the passenger side would get rid of the torque steer. maybe is it because the direction the driveshaft rotates? it doesnt really make sense to me. i understand about the push vs. pull on the shackle on the front of the bar and in my opinion i would think it would make more sense to be mounted in the "pull" configuration. anyway im just confused why the passenger or drivers side makes a difference. im trying to understand this so when i {darth vadar voice} come to the dark side {/darth vadar voice} ill be more prepared. thanks Think about the way a vehicle moves when you hit the gas. Body leans a bit to the pass side due to engine rotation, rear axle moves the pinion upward. Put the bar on the pass side and the pinion moving upward is transferred along the bar into an upward force on the frame countering the lean caused by the engine rotation. On the drivers side, this upward force is actually adding to the lean caused by engine rotation instead of trying to cancel it out. Done right, you can actually take off with the frame staying flat.

[OhioYJ]

On the drivers side, this upward force is actually adding to the lean caused by engine rotation instead of trying to cancel it out.Yeah Bill, next time we get together, watch me take off, you'll see how hard my passenger side squats. Thats why I've got that patched together leaf on that side.

[OhioYJ]

kwrangln, whats your take on move the spring center pin to a different hole in the perch? (I searched Pirate, and hearing a bunch of mixed things)

[olivesta500]

alright thanks kw and mike. it makes a lot more sense now. i guess when i come to the dark side next summer ill be putting the bar on the passenger side. thanks guys.

[kwrangln]

Originally posted by OhioYJ:
kwrangln, whats your take on move the spring center pin to a different hole in the perch? (I searched Pirate, and hearing a bunch of mixed things) Front and rear on my new heep are both moved an inch with spring perches. Go for it, as long as your steering doesn't bind (tie rod and drag link too close under flex), and your driveshafts have enough length to make up for it, your fine. Watch interference with your gas tank and rear diff, the 60 in the rear of mine will kiss the gas tank skid upon compression.

[OhioYJ]

Yeah both the tie-rod and gas tank are going to be really close, I know the front shaft is long enough, but I will have to lengthen the rear shaft, I may try and move the front tommorow.

Does my logic about moving the rear rearward reducing spring wrap make sense? Would making the perch longer on the side that tries to wrap upward help control wrap?

[kwrangln]

Moving the perch will help a bit with spring wrap, but not due to perch length or offset.

Picture a sine wave, with the axle in the middle of the spring, both ends of the spring are the same length and can twist into an S shape, a perfect wave. By offsetting the axle, one side of the spring is longer than the other, changing this point will have the two sides trying to stop each other due to form. One side can flex more than the other, an imperfect wave. Wish I had some pics to depict this. Falls directly under equal and opposite reactions.

The effect will not be enough to do without a wrap bar tho, case en point, waggy springs with the pin offset 2" are notorious for being soft enough that wrap killes em on a regular basis. Cherokee springs fall victim as well with a 6" offset pin.

Using perches to counter wrap is not a new idea, been done for years with the same results, bad. I ran RE extended perches on my black YJ, and without a traction bar, could wrap the rear springs enough to completely compress the slip joint on the rear shaft untill I swapped out some parts. Quite frankly, I'd skip perches as a wrap control method, they didn't work for me at all.

I've tried perches, single link, extra leaves, and finally the ladder type bars, with the ladder type wrap bar being the only one that works worth a damn. Cant even remember how many different mounts I tried in an effort to get the single link bar to work, it was a bunch. All these attempts were with the anti wrap perches in place.

[OhioYJ]

I'm keeping the wrap bar, I'm planning on moving it this summer too, so its on the right side.

I was just making sure I understand how everything is interacting, off setting it on the wave makes sense the way you put it.

Thanks kwrangln

[kwrangln]

No prob.

[OhioYJ]

kwrangln, I know you have a high steer setup on that rig, but hows it setup?

I'm still looking at mine and its pretty close the way it is, wondering how yours clears?

I guess I could move the one bar underneath the springs to the stock location, but I really don't like that idea.

http://i6.photobucket.com/albums/y249/mr5oh/histeer.jpg

[kwrangln]

Mine's a bit different. Drag link is in normal position, pitman arm to top of pass knuckle, tie rod and hydro ram are behind the axle.


Not the best pics, but ya get the idea.
http://www.the-jersey-devil.com/photopost/data/521/101MVC-012S-med.JPG
http://www.the-jersey-devil.com/photopost/data/521/10147b4db31b3127ccebe19c17c00de0000001610.jpg

You can get the double steering arms for the 44 from Rockstomper to run this setup. Clearance is a bit on the tight side across the top of the diff, but it all fits. Just have to be real careful that tie rod to balljoint and drag link to balljoint and ram throw are all equal or they will end up fighting each other.