tires out of balance?

[big marc]

its a bds lift and i ordered the shims today.

[big marc]

so i installed the shims and it still does it. iv tried every shim width and it still wobbles. i will never again lift a new truck! Anything else i should try before i take it to a shop?

[Pahrump]

Originally Posted by Lifted08SD

I have an 8" Rize lift & have exactly 2" of shims for the carrier bearing drop.
That seams to work perfect for my set up.
Rule of thumb - for every 1" of lift 1/4" of shim for carrier bearing drop.

I agree....I have a 6" and have about 1.5" of shims....no shimmy shake or rattles.

[big marc]

im going to put the stock tires back on it and see if it does it then. i cant even drive the truck it gets so bad!

[Rwalker]

try that, but if the driveshaft geometry isnt just right you are gonna have shimmy. you need to have your T-case angle match the rear pinion angle and the driveshaft has to be aligned properly too. the shaft may be out of balance too.

[big marc]

should a lifted truck drive like a stock truck? how would i check the angles on the tcase and the drive shafts?

[Pahrump]

Originally Posted by big marc

should a lifted truck drive like a stock truck? how would i check the angles on the tcase and the drive shafts?

Yes, pretty much.

[b_hugie]

A high speed vibration such as the one you are describing is not usually a driveline. I would check the front axle components first. Trac bar bolt, pitman arm etc. A dual steering stabilizer is a definite help if running a wider wheel and tire combination. If the driveline vibrates upon hard acceleration from a dead stop, the carrier bearing is to blame. shims will help this, but i have found that it also helps a great deal to angle the carrier bearing. shims will only drop it straight down. if you look at the side of the bearing, it needs to be perpendicular with the driveline, which will mean dropping the rear of the bearing more than the front in your case. hope that makes sense. another trick to to run less air pressure in your tires, some of these trucks come with 80psi in the rear tires stock. this creates a rigid support for all unsprung weight. we usually run about 40-45 psi. if you are still getting a vibration, pull the front driveshaft out, and drive without it. front shafts are more prone to vibrate at high speeds due to the shorter lengths and higher angles than the rear.

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Last edited by b_hugie : 04-10-2008 at 10:06 PM.

[somebodyelse5]

Dude, go right to the lift shop....thats what i would do...Cause you dont wanna end up with them saying YOU messed something up. The sooner you get it back to the lift shop and let them handle it, the better.

Thats what i would do!
good luck. And post up some pics!

[ZeroOne]

Sorry to hear you're having a problem. Some do, some dont, it seems. I am also one of the unfortunate. 8" lift (6" rear to level) and I've got the takeoff shudder. I have a fully adjustable carrier drop, and have also tried different pinion angles. Nothing will get rid of the takeoff shudder. There was also a higher speed vibration around 20-25mph and again from 43-48mph. Messing with the angles, (google "magnetic angle finder" for the tool), I found that having the carrier ujoint at almost a straight pass-through with most of the harsh angle being taken up by the tcase got rid of the higher speed vibrations. This did not fix the take off shudder and also allows a vibration that can feel like an out of balance tire at around 45mph.

Bottom line, it's easily fixed with the right driveline. I'm switching out to a new two-piece, but with a double-cardan at the center/carrier joint. Others have reported that they have NO shudder or vibration with this setup. I should know in a week or two when I get the new part.

Just sharing my experience. It's possible that some Ford drivelines are just more prone to do it because of manufacturing differences. Lots of guys have major issue and can't get rid of it, and others just add a shim and they're all set. It should be as smooth as stock, in my opinion.

Check this thread out:
Drivelines - those who are lifted