Vibration / Shimmy at Cruising Speed

Is it wrong to quote myself in the same thread, with an "I told you so"?

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Is that so they dont damage them when removing?

Yes, they will break. Be very careful when you remove them. They are delicate!

AA, all my weights are still on and the tires have less than 3,000 easygoing miles on them. Tire wear is not an issue.

Rotate the wheels and see if anything changes.

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Remember everyone, take those center caps off before letting them touch the car!

This is the FIRST thing that I do every time that I take the car in. I just pop 'em off in the parking lot before I walk into the shop. They WILL scratch the fuck out of them, or break the delicate little clips holding that metal ring. Let's face it - a terrible design, all around. I'm lucky that none of my caps are broken on my chromes, but on my alloys they were much harder to get off. I didn't break any clips but a few were already broken, and I can see why.

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Is it wrong to quote myself in the same thread, with an "I told you so"?

As long as you recognize that I already had the tires "balanced," but they didn't actually do the service even though they said they did. I ruled it out, as I should have... but in reality, I shouldn't have trusted the Firestone guys. Whoever balanced my tires this time did an awesome job.

Got the tires rotated, balanced, and the oil change with conventional oil. The car handles much better, and somehow the body roll was significantly reduced!!! Go figure! Anyway, all three services totaled $59.03 so that's good. Now all I feel is the slightest, faintest shake which is from the slightly bumpy roads on the highway.

I replaced my front pads and greased everything this weekend.My mild shutter at 70 went away.

Well, finally got the 95 Riv out on the road after weeks of cleaning the interior and getting around to replacing the supercharger coupler.

All went great except once you reach a steady crusing speed, then go to push the gas to speed up there seems to be a vibration. It doesn't seem to vibrate up through the steering wheel, but more of an all around vibration in the car. Give it enough gas and it goes away and goes fine, However, it will do it again when you need to hit the gas to speedup.


Not sure if that issue goes hand and hand with this one but thought I would toss it out instead of making another thread.

Another problem is that once you read 55mph on the speedo, it stops registering anymore speed. The car will get faster but the speedo never comes off 55mph until you start slowing down.

Any ideas?

Thanks!
Mike

Bushytea:

about your speedo: I've never seen this one before - could be a mecahnical problem in the speedo head or a problem with the VSS (vehicle speed sensor) maybe. Maybe someone who has seen this before will chime in. Maybe it's a feature intended to kep you from lying to the cops (honest ossifer it was right on thuh dubble nickel!) Else - time for the FSM...

As for the vibration on acceleration - there's one lower transmission mount looks like a rubber +. when it starts to go it allows transmission of vibrations on changes in torque - acceleration and gear shifting. Might be the problem.


Sounds like your car was parked for a long while.

Albertj

Thanks for the response albertj. I probably should have made my own thread about this but just seemed as good here. I finally found some info on the mount so I figure I will get the car in the air and check on that.

The car I know sat but I am unsure for how long. It has some little issues here and there still.

On top of the Speedo & Vibration, the battery light stays on and the traction control light comes on after driving for a few minutes. Also the previous owner did a VATS bypass that I am unsure of on how to fix.

Hopefully the mount is all that is needed for the vibration though.

The trans mounts cost around $300.00 each from the dealer, just so your not surprised.
There are write ups here under motor/transmission mounts, do a SEARCH, that will give you some alternatives.
Before finding this site I spent a little over $600.00 for two trans mounts and they are still to rubbery / soft for my liking. I'm going to try what ewoolfe did with the polyurethane soon.
After replacing the mounts and installing a front strut tower brace my vibration at highway speed went away.
I talked to a guy with a Grand Prix that told me he left the STB off after doing some engine work to take a test drive and the car had a vibration he never had before. Reinstalled his STB and vibration was gone. Doesn't seem like that would cause a vibration but in his case it did.

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I talked to a guy with a Grand Prix that told me he left the STB off after doing some engine work to take a test drive and the car had a vibration he never had before. Reinstalled his STB and vibration was gone. Doesn't seem like that would cause a vibration but in his case it did.

That makes sense to me, if there is another component out of whack (tie rod ends or bushings, brakes or mounts loose), the STB could help firm things up. I noticed mine vibrated less after installing STB. It begins to vibrate a very small amount from imperfect tire/wheel balance over a long period of time.

Did seven ever get his vibration at 70 cured? Everyone else brought in their problems, and we never heard from seven

What is the torque ft lbs required on each lug nut? Were lug nuts tightened criss cross?

I had a PA that would vibrate at 70 if the wheels were not criss cross torqued.

Just a thought.

This is an older thread. Many posts about vibration at speed have been merged here. We may never know if seven figured it out, but others have come up with a few good ideas.

Lug nuts are tightened at 100 lb-ft. Cris-crossing is required... not only for less vibration, but so the brake rotors do not warp.

Thing that gets me is that all kinds of things cause vibration in Rivs at highway speeds. Tire quality/construction; motor mounts; brake rotor warpage; wheel balance; wheel mounting (for instance not cleaning the rust off from behind the rotor hats and on the hub faces before remounting wheels, or torquing one of the wheel hub bolts down too far before the others are snug. And so on.

Albertj

Yes, it seems like a lot of factors contribute to vibration in this car. If you can nail them all down, you've got one smooth, quiet ride, though.

Alright, I got some time today to get under the car and check out the VSS connector and such to see why my speedo stops at 55mph and noticed what could be my problem with vibration when I go to speed up at around that same speed.

Here is a picture of what I think is the issue.

*Don't mind the grime everwhere. I fixed the leaks that were causing that build up*

Don - might want to find out what one of those ABS motors costs from Ed Morad.

Mike - what is in that picture?!?

Albertj

albertj wrote:

Don - might want to find out what one of those BAS motors costs from Ed Morad.

Mike - what is in that picture?!?

Albertj

That is the rear transmission mount that is circled. I just had to take it from the side. Cameras do not fit to well in that small area.

Blown rear trans mount will certainly cause vibration, but I wouldn't expect it to affect the VSS... if it works it should work all the way, if it's broken it should stay broke...... hmmmmm

deekster_caddy wrote:

Blown rear trans mount will certainly cause vibration, but I wouldn't expect it to affect the VSS... if it works it should work all the way, if it's broken it should stay broke...... hmmmmm

Yeah, that rear mount seems to be blown from what few pics I have seen of good ones.

Well I figured out my speedo issue. The little plastic piece under the speed gauge that tells the needle where to stop had warped and was catching on another plastic piece causing the needle to not be able to go any further. Gauge is working 100% now.

On the vibration its just odd because it doesn't seem to really affect the car speeding up or anything. It also only seems to really happen if you lightly give it more gas, if you full throttle it or so the vibration either becomes much less or is totally gone. I do not feel any issues with the transmission itself, all the gears are fine and there is no stutters or anything.

Thanks,
Mike

MIke, I think you have motor or trans mount issues. Did you look yet?

Albertj

So what is the consensus on a tire that wont cause a vibration around 70MPH?

Bert

ibmoses wrote:

So what is the consensus on a tire that wont cause a vibration around 70MPH?

I don't know if any good tire "causes" vibration. It's the wheel balance that matters. I think any quality tire that is balanced properly (Some Firestone shops use a newer machine that is very accurate) shouldn't vibrate (much). In my case, I had some slight vibration around 70mph that went away partly with STB install, and almost completely after replacing tie rod ends.

As tires wear, they may go slightly out of balance, and I've also had weights fly off. My feeling is, if the shake is very noticeable and consistent, it's the tire or wheel balance. But if it's very slight, or comes and goes, maybe the cause is something loose, allowing movement up front, like bad struts, hub, tie rod ends, or loose control arm bushings.

I've never had tires that vibrate at 70. Yokohama Avid V4s, Michelin Pilots and now Goodyear somethings (I forget right now). It's all about having them balanced properly and knowing you don't have a bent rim or warped rotor.