I installed the 2/4 drop this weekend - 2" eibach springs & bilsteins up front and hanger/shackles with bisteins in the rear.

I am now experiencing some vibration in the rear end until approximately 25 mph.

Anyone else have this problem with a 2/4 drop? What is the fix?

Do not have any new pics yet, but will post soon.

Any help is appreciated.

 

shims?

 

Had a 2/4 BellTech drop on my 00 HD with the same same problem & Harley#56 is correct, it was the shims (or lack of).
The 00 has a single driveshaft and I think the 02 has two. Don't know if this would make a difference, but do know I ended up replacing a "bent" driveshaft. Expensive lesson!!!

 

Just got shimmed. All is fine.

 

Where did you get the shims?

 

local shop - Cutten Customs - Houston, TX

 

how hard were they to swap out. how long did it take?

 

Did they tell ya how they knew what shims to use? We played guessing games on mine until a couple weeks ago. Glenn finally crawled under it and realized I needed more shim, not less. I have a 6 degree now. What did you end up with?...

 

Robert told me that i have the same set up as you.

 

You need to rotate the 2 degree shim on the bottom of the leaf spring. This means removing the u-bolts and loosening the center pin on the leaf springs(make sure you have a few c-clamps holding the leaf springs together)before you rotate the factory 2 degree shim. For any of you folks that have installed just 2 inch drop shackles, you must do this as well to remove the driveline shudder. The factory 2 degree shim is set to make the pinion 0 degree's. When you install 2 inch drop shackles, it points the pinion down -2 degree's. This is a no no with two piece driveshafts.
The stock 2 degree shim will point the front of the pinion down towards the ground when you install the Beltech or whatever brand shackle. This is not a problem on the Lightnings, because they have a one piece driveshaft and actually aids in traction. The two piece driveshaft on the Harley Davidson or SuperCrews are very sensitive to any changes in pinion or driveshaft angles. The HD comes with a 2 degree shim made from the same leaf spring material and is hard to notice at the bottom of the spring pack. In stock form, the larger end of the shim is to the front of the truck. This sets the pinion angle at zero when stock. When you install the 2 inch drop shackles, this now points the pinion towards the ground 2 degrees. If you rotate the shim to put the larger end towards the back of the truck, you will now bring the pinion back to zero. Looking at the shim from the side, it will look pie shaped(taperd). Remove the spring u-bolts and clamp the springs with c-clamps. Loosen the center pin on the leaf spring(wrench and vicegrip) and rotate the large end of the shim toward the back of the truck. Tighten the Center pin and reassemble. Very easy job. Make sure you do not tighten the shackle bolts until the truck is on the ground or it will cause the bushings to bind. Good Luck. I know I have read many post on HD owners installing Shackles only to remove them because they cause vibrations. This will cure it!!!

For those of you that have added a 5 or 6 degree shim, I would remove it and follow these procedures. What you have done is just add another shim on top of the factory shim.

 

Hmmm? Thought provoking, to say the least. I wish we had thought to try that.
We did use a 6 degree shim on mine, but we removed the stock 2 degree shim. I still think there may be a tiny bit of vibration, but I drove it straight home after the swap from 4 to 6 degree. I haven't had it out since. I plan to get her out Saturday night, so I will report the results.

BTW- My truck is lowered with hanger, and shackle. The shackle is moved down one hole to give a total of 4" in the rear (including factory 1")...

 

N2TRUX, all bets are off with adding the hangers into the equation. I have not installed hangers, but I believe the aftermarket hangers actually move the front of the spring up, towards the bed of the truck and away from the ground. This now points the pinion up which would some what offset the shackles. I am out of town right now, so I dont have the stock angles handy. I believe that my pinion angle was at 0 degrees measured at the face of the pinion flange and 4 degrees on the rear portion of the two piece driveshaft. You can pickup a cheap angle finder in Home Depot or Lowes for less than $10.00. I would suggest that any of you guy's that lower your truck, take measurements of the pinion, both portions of the driveshaft and the rear of the transmission before starting.

One note: I remember that Outnumbered only installed the hanger from his Belltech kit and did not have any vibration and did not change the shims. This leads me to believe that the pinion angle set positive(pointing up 1 degree ) has less of an effect than pointing negative(towards the ground). The negative angle increases the likelyhood of vibration. Try and set the pinion angle at zero and keep the driveshaft within 3 degrees.

 

Richo & Moomba,
I think I have an anlge finder. I haven't used it since my 4wd days, and that's been a while. I'll see if I can't get under it and, and give more data. If it doesn't rain, I plan to take her out Saturday night. I'll know then if the vibration is gone or not.

I guess we need Harley #356 to put together a data base on lowered Harleys...

 

ya give me the info, i'll make the thread. LoL

going to do one up some day when i get spare time for tonneau covers on HD's. I did one before, but couldn't find all HD's for the pics. It'll come in handy when we get a bunch of 03 HD newbies and they ask the same questions the 02 and 01 guys asked.

then i'll probably do another one on drops and pics of each. just need to find the time

I also did one on how to post pics and did it step by step, but i can't find it anymore...forgot to put it in my favorites. i'll have to search for it, cuz it wont' be too much longer when we get a bunch of new members on here with 03 HD's and will be asking how to post pics, etc. etc. LoL

 

o.K. Josh...how bout a newbie with an 02. How do I print Richo's response without printing the whole thread (everybody's response) and how do I get it to print where it doesn't cut off the right side (this is the only site that I have this problem with).