I just noticed the other day that from about 66-73MPH I get a fairly nasty vibration in the rear. I'm just now noticing it because I am seldom on the highway riding at a steady speed. Alot of city driving averages 20-55MPH. On my "test & tune" road, I dont guess I was in that vibration "window" long enough to notice any problem. Before the Hotchkis leafs I had the stock leafs with Belltech 2" shackles and the shims removed, all was good. Now the truck definately sits lower in the rear than with the Belltechs, so maybe I need to put the shims back in, but flipped the other way?? I'm not REAL sure on the most accurate way to measure the pinion angle. To my understanding, the driveshaft to rearend input shaft should be a STRAIGHT line? I'll look at that in the morning, I'm at work now. Whats the best way to measure that? Thanks in advance.

 

Here is some good info:

Archive linky w/ pics

You can use a parallelogram protractor to measure the angle, but you're going to need to find a baseline from someone with the same year truck and stock suspension - so you can get your pinion angle as close to stock as possible. The year of the truck you're using as reference is important, as the Bilsteins raised the rear a bit in 01-02, and 03-04 L's have the Bilsteins + stronger springs (and higher ride height in rear).

 

I finished installing my 'new' TVS yesterday on my '03 lightning... I feel a similar vibration. At street speeds there is no vib. At 70ish there is... Above that...80+...no vib...even hit 120...felt smooth as fucccccckkkk.

 

Thats right!!!! Same thing I'm talking about, pinion angle has GOT to be off now. I'm gonna try to check mine this weekend. I have a protractor, so I'm gonna see what i come up with if i can fit my fat *** under my truck now that its lowered. LOL

 

Sorry to hijack the thread but you got any pics yet Amo? So how does the total package ride and handle compared to stock?

 

Sorry for the delayed response, but I just got my camera back, i will get you some pics prob by wed...love the way it looks, but I need to figure out how to stop that damn vibration.

 

When you put the springs on you took out your drop shackles? Well, when you change springs it shouldn't change pinion angle. You need to put the shims back in.http://www.carcraft.com/howto/91758/

 

http://www.nloc.net/forum/showthread...threadid=73879

I was chasing a vibration I had at 65 and up. Changed shims, sizes, direction and never got better, only created new vibrations with bigger shims at around 25mph. Come to find out the tires were out of balance. After I had them balanced I marked the inside egde and after about two weeks the tires moved on the wheel between a 1/4 to 1/2 inch. Hope this helps.

 

Finally got some pics. Not the greatest picture, but I will get some better angles soon. BTW, I LOVE the way it handles... Solid, great handling. Love changing lanes at 100. I ordered Hotchkis Bilsteins, which should be here soon too.