Topic: Crazy vibration

[Gr8Ride]

Hi folks.  If you recall, I was having torque steer and wandering issues last (well, if you don't include the broken tooth in reverse).  Anyway, just wanted to pass along my thanks again for all the responses; new issue now.   Went ahead and bought some used aluminum wheels and had a set of BFG lookalikes (31x11.5) installed.  The rims don't have a lip on the outer edge and while I was perusing a 4x4 mag, I ran across an ad for this stuff called "equal"...  It's a bag of sand-like granules that you drop in while mounting the wheels and it balances your tires for life - no more lead weights.  So I bought some and asked the guys installing the tires to put the stuff in.  I watched them scrape off the stick-on weights from the rims and put the stuff in the tires.  Driving home I noticed a vibration from 40mph on.  It actually increased tha faster I went but under 40 was barely noticeable.  After a couple of days of driving, it seems to be worse now (more intense) and occasionally, it appears as though the harmonics even out and it subsides a little then comes right back.  Only thing I changed was the wheels and tires; the rest of the stuff on my profile is new since Sep last year and I've only put 3000 miles on it since then.  I rotated the tires to see if that made a difference - NADA.  Checked all nuts/bolts and regreased  - NADA.  Seems to be much smoother if I put it in 4wd and the front wheels are pullling but when in 2wd, I feel it through the steering wheel and shifter and can see the front fenders dancing (drivers more so than passenger side).  Thoughts?  Think I need to can the "Equal" and get stick-ons?  Think I could've exacerbated an existing suspension or driveline issue going from 235's to 31's?   

[Bounty Hunter]

It's not the 'equal', internal balancing works.  I used DynaBeads in my current set of 36" TSL's, no problems and they're generally a difficult tire to balance.

I would suspect a bent rim, or other mechanical problem.

[Gr8Ride]

Well today, it actually smoothed out on occasion to and from work...actually drove like all was fine for 30 sec intervals before the vibrations would sart again for a few minutes.  Sometimes bad, sometimes only noticeable.  WTFO?!

[Mozman68]

Did you do the old "jack up the front end and wiggle the tires to see if there is any movement" crap yet??

[Gr8Ride]

Hey Mark, have been TDY and unable to get to the site...yep, did the whole "is anything loose" investigation - nothing.  Have also noticed it sporadically, as in sometimes it's bad @ 45, other's not.  Same at 60 - appears to actually smooth out while other times not so much.  Range is 45 on up but doesn't necessarily get worse the faster I travel.  Definitely feel it in the steering wheel and when it gets going I can see the front fenders dancing up and down.  Alignment seems good (1/8" toe in) and everything's greased up.  Here's a question - could it be the shocks?  I put on new rubicon shocks when I put the rubi springs on but I went ahead and added the 2"BB so could it be that I just don't have enough travel in the shocks and it's creating some sort of periodic harmonic dance?  Strange though that none of this was occuring when I had the stock 235's on.  I've either exacerbated an existing problem or the tires aren't balancing out.  Thoughts?

[Jesse-James]

Have you checked your stabilizer shock? disconnect one side and see if you have resistance.

[Gr8Ride]

Was a new trailmaster when I did the spring replacement in Oct - haven't done any off-roading since so can't imagine it being bad unless it was just crap to begin with.  Didn't appear loose when I did the inspection but didn't actually disconnect and test either.

[Oilsmoke]

I once had a BigO 33x12,5x15 on my Old 3/4 ton 71 chev 4x4 and at 39 to 41 mph i got a real bad Bounce out of one tire, Road pressure Test on a Computer spin balance put it out of spec and They replace the tire but i had to fight for it. It fixed the problem .

If you have it on one side swap the tire to the other side and Test to see if the shake follows the tire, if it does test the tire.
I hope my problem leads to a answer for you.