Vibration / Shimmy at Cruising Speed

Abaddon wrote:

40lbs....jesus. You can usually balance well up until about 20lbs, but 40??? lol. Glad to hear you got it figured out.

We warranty any tire that produces anything more than 18lbs (after variation correction) at work (GM spec).

Yeahhh I don't think I really emphasized, the ride of the car was pretty high on the "I think I'm gonna die" scale so I just drove at or below 65 for a little while which is definitely not me lol. I'm sure ppl passed all the time going "Look honey, another slow-ass Buick."

I think I need get tires done at your work! Tbh I think the old 04 tire was put on there before I even got the car so I have no idea if it would be under warranty still  

Why do I only have vibrations between 70-80mph? Anything less or more is butter smooth but in that range, it feels like the whole car might shake itself apart.

Any idea what is getting weird in that speed range?

would rotating wheels/tires from the front to back help diagnose anything?

Are there any mounts that I need to check out?

Any tips to point me in the right direction?

Mine does it only b/ween 65/70 mph.

I thought the new axle "alleviated 96% of the vibration". Did it come back? Or are you still trying to suppress that last 4%?

(in almost every case, this type of vibration can be attributed to an unbalanced tire or out-of-round wheel)

It for sure made a difference, but it's not completely gone. It narrowed the range now. Before it was 65-85. Now its 70-80. I want it gone. ALL GONE!


That's great news! Do you think if I put my rear tires up front, there should be some kind of difference, right?

There must be a way....

In theory, if it's coming from a front wheel, you feel the vibration through the steering wheel. If it's from a rear wheel, you feel it in the floor and seat.

Ya know,any kind of hard stop where you really slam on the binders,can ruin a good tire balance in a mater of feet.take it out the tire store with a 4way balance,turn the corner,garbage in the street!slam on the brakes,balance gone.That fast.My car ran super good at any speed with no issue.Couple of hard stoppies and now she kinda vibes at 70 to 90 & above. It sux not being able to balance our own tires.I been thinking about getting the cheap HB balancer.Some say it works,ya just gotta mess with it a bit to get it rite.   If the pivot points are new,tie rods,ball joints,etc, it's almost always the tires.
Harmonic Vibrations can set in on older model cars with super soft factory bushings.Vibrations start to play & they wont stop until the whole car becomes annoying. I know this because,hard mounting most of my suspension has eliminated most of the really nasty stuff. I can also say that my Riv has held it's alignment incredibly well up front since my coil-over mod.It's uncanny !

Robo, I think that happened because the bead sealer was still wet when you first left the shop, so the tires rotate on the rim. If you wait a day or two before hitting the brakes hard, the seal is cured and they won't slip. I read a thread on this once - it's happened to a lot of folks. Wait before you brake!

Well that's odd. The bead sealer we use is dry by the time the tire gets mounted. You might be talking about the soap that's used to actually mount the tire, not a bead sealer. Yes, you can spin the wheel inside the tire if that soap isn't dry yet. I've done it before under acceleration after mounting tires....

I think you're right. It might be using too much lubricant causes the slip (according to Toyo):

(PDF download)

it can happen way ahead of that too. A bead can slip.Take a marker and bisect a line tire/rim.take measurements over time and watch the line move. once it moves,the tire is no longer balanced.It's only natural.

Makes sense. I've had tires go out of balance over time, but never all of a sudden from a hard stop. I've braked to -.55 G on my 18" wheels. That's pretty heavy.

Maybe it's like the Toyo paper says - there's a problem if they use too much lube.

Just reading about this, some track racers actually screw their tires to the rim!

I find most new tires should be rebalanced after about two months of driving anyway. Once the belts and materials have settled, so to speak.

I can't stand bead sealer. If the bead isn't sealing, find out why. If the rim is pitted and corroded, fix it! Bead sealer just makes it even worse for the next guy.

Every tire I've had with leaky beads, I got the beads sealed up by using a rust wheel to take away all the dried up bead sealer and corrosion. Sometimes re-clearcoating the bead area was necessary if it was pitted badly. Never a bead leak after getting rid of the bead sealant. Bad stuff.

Consider replacing the front control arms.

charlieRobinson wrote:

It for sure made a difference, but it's not completely gone. It narrowed the range now. Before it was 65-85. Now its 70-80. I want it gone. ALL GONE!


That's great news! Do you think if I put my rear tires up front, there should be some kind of difference, right?

So has anyone announced the solution to this problem yet?

Not yet....

I have been sifting thru it all but I went to sears and they put it on the lift for me. Right at the base of the cv boots meets the differential, it does not go round in carousel motion. It turns in like a jump rope kind of motion more on the passenger side tho. He said its caused maybe by my sagging suspension

I theorize that most if not all of the Rivs vibe problems begin with the very soft bushings.For an allmost 4000 pound car, the bushings were at that time in technological terms way under par.The weight of the Riv just messes about with the mushy bushings and creates a myriad of technical problems. I never had a car that lost it's alignment as quickly as the Riv.Since hardmounting,I have not had one single alignment or vibration problem.Of course, I live in Vegas,streets are super smooth.

The pot holes here are not worthy of any car and my 35 tires expose my failing suspension constantly, so robo you are saying poly mount all the rubber bushings on the car ?

...so it's the bushings now a?

Johnny5 wrote:

The pot holes here are not worthy of any car and my 35 tires expose my failing suspension constantly, so robo you are saying poly mount all the rubber bushings on the car ?

I say if you can find some then by all means thats what ya gotta do. there isnt one enthusiast on this site who would be content with their OEM bushings after riding in a Riv kitted all the way around with poly bushings.None.The increase in harshness is silly compared to the safety and road holding poly bushings would give to such a big coupe.crazy.
Getting any kind of bushing in the Riv is a major pia.9 out of 10 one would opt to buy new control arms.

stan wrote:

...so it's the bushings now a?

Of course.If the soft bushings allow constant toe in & out and changes in caster constantly while you drive,what else is it? its a major factor. Address the oem bushings and ya might have something!

I need to find some one reasonable and trustworthy to do the robo suspension. And the 97+ knuckle and control arms upgrade should be a direct bolt in right?

I think im going to opt out I just wish there were more options for our "Tuxedo" "Bonneville"