I just installed 2" drop shackles on my 2003 F-150 XLT SuperCrew and new 20" rims with 275/45/20 tires. I notice at 62 mph I get a noticable vibration in my truck. I've read here on the forums about lowering the rear changes the pinion angle and need to correct it with shims. I read an article on the forums here about rotating your stock shims 180 degress. I did this today and the truck still has a noticable vibration. Do I need to install 2 degree shims and turn my stock shims back or leave them they way they are or do I need more angled shim? Should the driveshaft be perfectly in line with the rear end, because I looked at my brothers truck today which is the same as mine but a stock truck and his rear end has a slight angle to the driveshaft.very similar to mine. Please help I'm getting a little discouraged.

 

Samething happened to me on my 01, took it in and had the tires re-balanced. I had thrown a weight off and it was causing the vibration. You might want to check and hope this helps... Pat

 

We looked at the weights after they installed them and he said they looked to all still be there. I just had them installed on Friday and probably have less than 100 miles on them.

 

When I originally dropped mine, I noticed the same... but similarly it was a tire balance matter that was not noticeable at the stock ride height. My tires were "properly" balanced by the guy who'd originally spun them... but he must have been in a rush because they were seriously off balance. Re-balancing solved these woes.

Know what else? I blamed this problem originally on my Hotchkis 3" springs... sold them at abotu half what I paid for them...only to realize later that it was a tire matter from the start!

GRRR!

 

Had my tires rebalanced today from a 4X4 off road center and they said they recalibrate there balancing machine everyday. One tire was OK but the other 3 he said were way out of balance and remember I had just paid last week when I bought my rims for balancing so consider that money in the trash. Drove it and the vibration has stopped and rides smooth.

 

Glad to hear the vibration stopped! I would take the new receipt back to the original tire guy and ask for my money back due to **** poor service.

 

I probably would if they weren't friends of mine. I did tell them about it and that there balancing sucked. They did take off my stock rims and remount the wheels back on for me though....lesson learned.

 

Some with screws have rotated their stock shims with great success.

 

I had already done the shim swap but vibration continued. Ended up being poorly balanced tires. I guess I'll just leave the shims the way they are, cant' hurt.

 

Its hard to find a "good" guy for tire balance. I now go to Americas Tire where they have Hunter that does a road force balance. They come out great every time...