HELP: Vibration hunting, any ideas??

[David_VT]

Hello all,

After a set of tires, three wheel balance attempts,etc, I am searching for ideas regarding properly troubleshooting vibrations in my truck.



History:

OEM tires + all my toys = smooth ride

above + JDclutch = neck snap launch but smooth ride

Install new tires = nasty vibration in rear



Vibration characteristics:

with or without power,

no steeringwheel vibration

gear shift has slight vibration

right and left mirror vibrating enough to blurr reflection

cap shell rear window vibrating like crazy



Troubleshooting history:

Rebalance all tires at 2nd shop= no change

2nd Rebalance all tires at 3rd shop = slight improvement

replace most difficult to balance tires = no change



==========

So: if the new tires are not the problem and the tire shop is starting to complain about all the horsepower toys in the truck, where do I go next to prove / disprove that the BOMBing is not the source of the vibration? (old tires not available)



Is there a good technique for isolating the source of such vibrations.



Open to all suggestions, under the gun for an 18 hr tow job this coming weekend.



David

 

[willyslover]

David. . remember the mud... did you have clean rims when they balanced it ??

did they warp a rim [on the changer machine] as the factory rims are very cheep ones with weak centers. . check wheel run out. .

Luck to ya buddy

 

[Don M]

Steering wheel vibration is almost always the front wheels so it looks like your front wheels are ok.

Check the run-out on the wheels first. I raised my truck in the rear with it running and got it going about 50 MPH per the speedo and could very easily see I had a bad tire. Yes the tire was new and the *astards at National tire and Battery have yet to replace the tire. We are still going around and around.

Its kinda dangerous to run the truck in the air like that though.



The wheels have no wooble to them at all but you can clearly see the tire flopping around from side to side not up and down in this case.



Don~

 

[David_VT]

RIMS?

Willys,

I was wondering about the rims... .

Who makes a rim that is near to our OEM rims but stronger??



The mud is long gone but I did notice that one of the front rims has a slight defect in it. It balances with ease.





I was wondering if something can degrade in the clutch assy after several thousand miles of vibration free operation that would introduce a vibration. One guy at the tire show hinted that I might have thrown a harmonic balancer... What the heck is that?

 

[nps]

David,



Harmonic balancer is what sits on the front of the crankshaft, and the lower accessory pulley bolts to it. Sounds like the shop is trying to pull it out of their a$$ to get you out the door.



Thinking wheels. Have you tried swapping front to back to see if the vibration moves to the front.



Definitely check the runout. Easy to see on a tire balancer. Take any small, straight piece of metal or wood (1/4" extensions work good), hold it just off the outer edge of the wheel (check inside and outside edges), and give it a slow spin by hand.



If you didn't feel the vibration before, don't let them talk you into anything other than what was touched during the tire change. A lot of things can degrade the clutch, but none that I can think of while it is on the rack.

 

[Steve Campbell]

I found out the tire changer at the tire shop purposely removed the balancing weight on a rear drum because an aluminum aftermarket wheel would not fit with it on(89 suburban). Lots of vibration until I bought a new rear brake drum.

 

[fest3er]

Originally posted by David_VT

Hello all,

After a set of tires, three wheel balance attempts,etc, I am searching for ideas regarding properly troubleshooting vibrations in my truck.

...

Go to the hunter.com web site and find a tire dealer who has a Hunter 9700 'EOM matching' balancer. The machine will find out-of-round tire/wheel combos real quick.



Sounds like you might have a high-spot/low-spot mismatch - meaning you might have a tire/wheel combo that is not round. It's easy to see. Jack up the axle and ensure the tires do not 'move' up and down as they turn. They should appear nearly perfectly round. If not, have them turn the tire on the rim 180 degrees and see if that helps.



Fest3er

 

[JAnderson]

Make sure they are not putting alot of weight on the rim. I had one that they put a weight that encompassed over half the rim. Bad vibration. Made them rotate the tire on the rim and rebalance. Only used a tiny weight and vibration gone. Definitely swap front to rear like someone posted above. If vibration moves to front guaranteed a tire/wheel problem.

 

[Devildog]

Is the vibration still there with the clutch pulled in on in neutral?

Also the tires could be out of round from the factory, have the tire guy spin it up on the balance machine and see what it looks like, some shops have a tire lathe to make the tires round again, but being new you may want different tires. Good luck.

 

[DaveN]

also have them try to turn the wheels on the rims. iF you look and you have all sorts of wheel weights, the tires are not going to run balanced even though they tell you "their machine say's they are ok". Ran into this on my old truck, I had them break the bead, turn the tires on the wheels (I told them 180 degrees but some guys say 90, I don't know... ) and rebalance. Went from 6" of wheel weights to a little bitty one and no more vibration.

 

[David_VT]

thx for the inputs

Looks like the tire shop finally got it fixed.



Maybe the second tire was not really swapped as reported to me and they just tried to rebalance it and choose to tell me it was replaced. ... . who knows...



Regardless, the vibration is back down near normal.



Don't you hate the fact that once you start to be effected by vibrations you can never really ever be confident again that any little shake isn't a new problem...