Vibes; Not just tires

[gavin]

ok.. so it's kinda a long story as to this whole problem I've been having.
A couple years ago, after I got my body lift done, I bought some used 33 BFG AT's, and some new Pro Comp 1069 Series Extreme Alloy rims. They got mounted and balanced fine.
I then always had a fairly bad vibration, that only got worse after time. I took my truck in twice to get the tires re-balanced, and finally after the 2nd time I was told my "tires" were out of round. Ok, they were used. And when they told me tires, I assumed the rubber and not the rim (well.. I shoulda asked).
Later on down the road, I found a used spare (so I had one).
So out of curiosity, I replaced one of my tires with the spare, and a lot of the problem went away. So I knew one tire/rim combo was bad. Well, shortly after I got a nasty irrepairable hole in a tire, so on goes the bad tire again.

I finally got enough money to by some new tires. Same issue, except now it's even worse (prolly due to heavier tire). With 1 tire in particular, I ran it on the driver's rear, and would watch it through my side mirror; I can see the tire wobbling. Ok so that tires bad. I buy another new rim/tire combo. Remove the known-bad with new.

Still having the issue.
So I'm pretty sure it was supposed to be "rims" out of round. (I'm takin the tires in to verify rims are bad so I can get the replaced under Pro Comp's limited lifetime warranty)

Anywho.. so I go and put my old stockers back on yesterday, and there's still a nasty vibe. Not as bad, but it's there. And I have no clue what it could be.

I guess the main question of my shpeel is, other than tires being out of round/out of balance, what else would make the vibe worse with larger tires?
Let's just say both sets of tires are balanced and round. What would cause a vibe to get worse with the larger tires?

I've already checked balljoints and wheelbearings, and they're good. I haven't yet checked my d-shaft ujoints yet. I replaced both my half-shafts just a few months ago. Tierods look to be in good shape.

 

[Mbrooks420]

I had a bad vibration that was caused by a failed u joint in the rear shaft. Mine was bad enough to be visible. I'd guess that heavier tires would aggravate any vibration cause by something loose in the driveline.

 

[gavin]

somehow I didn't think of it.. but a bent axle housing or shaft could cause this. But I haven't done any wheeling, or anything that would cause a shaft or housing to get bent.
but is there anything else?
I just went out and checked everything... u-joints on rear d-shaft are good, u-joint and cv-joint on front d-shaft are good, steering is good, balljoints and wheel bearings are good. both half-shafts are good. spent a good hour and a half @ only 7* outside... brrrr!

also, for giggles, I took my angle finder to my front half-shafts. Barely 10* on the cv's.

 

[gavin]

would a bad alignment cause a harsher vibration in the front end with the larger tires?

 

[mittelmeier]

Did you check your rear bearings too or just the front? With you being able to watch the drivers rear wobble it sounds like a bad wheel bearing or a bent axle. Is there any axle fluid leaking in the back? If somethings bent that bad you should have a fluid leak. If all that's ok I'd check the mounting surface for excessive rust buildup. I chased a vibration on a guys car for 3 hours one day because he changed his rotors and didn't clean the hub. Just my two cents worth.

 

[mittelmeier]

would a bad alignment cause a harsher vibration in the front end with the larger tires?

Yes it would. Any problem with the steering or alignment, or bearings will be multiplied by larger tires.

 

[toypaseo]

Do you have hubcentric rings...?

 

[gavin]

ok I'll try and answer everything in order... lol

rear bearings - not sure how to check them, without pulling the axle... and I'm not gonna do that when I gotta work outside in the snow at ~10*
But I do not feel ANY play (except for the very very slight in/out motion due to being a c-clip axle). Also, with the new tire/rim combo I got, there was no wobble from the driver's rear (which is where I first put it).
No loss of fluid from anything.
I've also moved all my tires around onto all 4 corners; I do not remember noticing any excessive rust buildup.

I am chasing it down to an alignment issue though, definately. I got bored, and so I took my angle-finders out. As long as I'm measuring correctly (well, to the best of my ability with the tools I have, which I believe I am), the pass. side tire had massive negative camber. So I did a shadetree alignment; which so far, seems to have helped immensely, except for the fact I put a bit too much positive camber instead, which I'm about to go fix
But I am leaning towards alignment.

hubcentric rings? eh? sorry I'm not sure what those are

 

[toypaseo]

This is a pretty good explanation of hubcentric rings...

http://www.justforwheels.com/index.jsp?cat=hubcentric&sub=how&track=WM

I am not sure how it applies to big tires though.

Hubcentric rings solved some vibration problems I had in the past, but that was with 15" aftermarket wheels, and 195-50-15 tires.

 

[gavin]

This is a pretty good explanation of hubcentric rings...

http://www.justforwheels.com/index.jsp?cat=hubcentric&sub=how&track=WM

I am not sure how it applies to big tires though.

Hubcentric rings solved some vibration problems I had in the past, but that was with 15" aftermarket wheels, and 195-50-15 tires.

huh.. interesting product.
but since that's what they are, then nope.

and I believe I got my alignment much better than it was before, now. I'll find out tomorrow on my way to work.

 

[gavin]

well I think I've determined what *part* of my issue is.
that stupid pos f-in driveshaft.
#3 in 5 years.
I'm pretty sure the CV is going out.... again... without any rips in the boot.
pulled it out and greased the u-joint best I could, and got some more grease into the CV-joint. Also went ahead and greased up the rear u-joints.
Will see how it feels tomorrow.

 

[MountaineerGreen]

Psssst- BW4406 swap time! Get rid of AWD and that silly CV driveshaft.

 

[gavin]

lol
I actually like the AWD.
I just don't like the 12mpg I'm getting, even with my stock pizza cutter tires

 

[gavin]

well, I'm not sure if greasing it up helped at all.
Something I did notice on my slow drive to work; at slower speeds (under 30mph), it was very noticeable that something is "grinding" it just has that feel.
Above 30, though, it's still noticeable that there's binding, but doesn't feel as bad.
Yet, there are no noises coming.
I just want to make sure I'm in the right direction for the d-shaft.. although I am pretty sure that's what it is... but every time my shaft went bad before, it made a horrid clanking noise at just about any speed.

I think I'm gonna go pick up another from a junkyard anywya... $125 I think is what it was, ain't too terribly bad. And then I'm going to look into getting a custom double-cardan shaft made.
ugh.

 

[gavin]

ok... so some more info.
I just got back in from dinkin on the damn thing some more.
I didn't get another driveshaft, because the only salvage yard that had one, it was missing the aluminum cup, and had (apparently) fallen apart when the shaft was removed.

So... I removed my shaft again, and really greased the hell out of the CV and u-joint.

now... after I put the shaft back in, I very very slowly drove back and forth in the driveway; there's definately something binding. I kept feeling a "clunk."
at first I thought a cv-joint, even tho I just replaced the half-shafts. So I jack the front end up by the frame, and both front tires spin easily, and smoothly. So I doubt it's a halfshaft.

I try and do the same with the rear; it's a royal PITA to spin those by hand. I had to put all my weight into it. Now, with both rear tires, when I spun them, I heard a "click" and felt a slight grab. I'm honestly not sure how "normal" this is. And I feel the same thing from both tires.
Possibly a bad bearing in the rear diff? rear axle bearings?

So far that's all I can think of as the culprits; the front drive shaft (still), or something in the rear axle.

The fluid in the rear was replaced a couple years ago.

 

[gavin]

last post for the night..

I was talkin to my dad, and he suggested the rear breaks.
well damn, I can't say I've ever done ANYTHING to those.
That could also explain why the tires are so difficult to turn by hand, and could also explain why my fuel milage has bombed to under 13mpg, even with my stock tires. 3 of the last 4 tanks of gas; first tank, just under 12, next tank just a hair over 12, and after this last tank, just a hair over 12. Even with letting my truck run to warm up before I leave work, and before I leave work, should not kill 4'ish mpg.

I'm gonna try and stop and get some new rotors and pads tomorrow after work; damn Alaska's short daylight hours in the winter... lol

 

[Mbrooks420]

I wouldn't think it's the pads and rotors, I'd guess it's the parking brake drum/shoe setup. I had these stick on my other truck, and it really drug it down.

 

[gavin]

yeah my dad thought maybe my parking break too... possible, I guess.
Although I've *never* used the parking break, because it was never adjusted right.

went ahead and picked up new pads and rotors anyway, and just gonna remove the parking break shoes and hardware.

 

[gavin]

ok so I just got back in from checking the brakes.
rear brakes are good.
parking break shoes are good.

then I realized how I forgot that it's AWD, therefore it will be hard to turn the rear tires if the fronts are on the ground!

I get the rear axle in the air with jack stands, then proceed to jack the front end up.
takes enough force to get the tires to spin, but that's about normal.

But... I hear a screeching/squeal sound and I think, okay, brakes.
Well I decide to crawl underneat and turn the d-shafts, instead of just the tires.
Rear turns fine, hearing the squeal.
crawl to the front and spin it; hear the squeal.
and this screeching/squeal noise is coming from my transmission! I hold my head up to the tranny pan and can hear it clearly.

now... how normal is it to hear a noise from the transmission, when it's in Neutral, and turning the tires/d-shafts by hand?

 

[gavin]

well... I went ahead and just removed all the parking break crap, and figured since I had the parts, replace the rear rotor and pads too, just for peace of mind.
Gotta let it warm up a bit then I'm gonna head off to get the alignment fixed and the tires re-balanced.