Vibration / Shimmy at Cruising Speed

Gee, I thought "we" mentioned bent wheels????

madrivage wrote:

AA,I agree with you 100% it's just painful to the wallet at this time.

Abaddon,I just had a 4 wheel balance at a very reputable shop on a Hunter roadforce machine no less.Wouldn't you think they would have noticed a laterally bent wheel??Not doubting you at all,just that Hunter machine is the dogs bullocks apparently,and I can't imagine a machine as sensitive as that not detecting a bent rim.

BTW after the trans mount being replaced it is much better,but I still feel it a little around 70mph.So I guess it still is a rotational issue?

the Hunter 9700 is great but won't pick up a bent wheel. However the case makes it relatively easy to use a dial gauge (with a magnetic stand) to find a bent wheel. Your real problem is finding a tech who knows to do that. THAT is not so often the case nowadays.

Albertj

Quote :

Gee, I thought "we" mentioned bent wheels????

I thought it needed mentioning again.

(is there anything else he hasn't replaced?)

I have had this vibration to one degree or another through 2 sets of tires.
With everything balanced properly and having a Hunter Road Force balance done you ARE looking at replacing the wheels with a good quality aftermarket or something off another GM front wheel drive that you may like.

The final solution isn't cheap, but getting to the solution isn't cheap either.

I have let mine go for this long due to the fact I don't have to run on the highway that often, most of my miles are done below 60 mph, But I keep telling myself, this year is the year I get new wheels and something always seems to suck the money out of the budget.

If I were on the highway everyday for work, I would have found the money for wheels by now.

At this point I would go back to the place you bought the tires and tell them you aren't satisfied, or you think one of the tires has a problem. Explain the issue and the steps you've taken (a lot of steps!) to address it and you are back to the tires being the core of the problem. They should be willing to take one new tire and replace your old tires one at a time followed by a test drive until they find the bad tire. When they find the bad tire then it gets replaced under warranty.

It sure sounds to me like tires at this point.

i would also check,if you havnt allready, the front subframe bushings.if these are out,at speed ,the subframe is allowed to move and sway.since everthing is attached to it,could be a problem?

robotennis61 wrote:

i would also check,if you havnt allready, the front subframe bushings.if these are out,at speed ,the subframe is allowed to move and sway.since everthing is attached to it,could be a problem?

To add to that make sure the frame isn't rusted through or anything. Mine was, and it was the issue as far as my vibration. Apparently the K frame loves to rot on these....

madrivage wrote:

Well,new front hubs,new front struts,new rear trans mount,road force balancing ,pressure at 30psi,lugs hand tightened to 100ft lbs in a perfect star pattern...STILL VIBRATES AT 63-75 MPH!!! W T F????? I haven't changed the tires as of yet cause they still have a lot of meat left on them,but I'm running out of patience with this.Has anyone tried using DYNABEADS to clear up this issue??? http://www.dynabeads.net I'm willing to try anything at this point.

I have been down the same frustrating road and have determined with a dial indicator that I have a slightly bent wheel. Even though it all balances out on the machine, these cars are super sensitive to the wheels being out of true, just a little bit, for some reason.
Other cars are more tolerant and won't vibrate over such a small anomaly on one wheel. But this car does.
It shows up as a vibration on smooth roads between 60 and 80 mph and you feel it in the seat, floor and steering wheel to some degree. Very, Very friggin annoying.

I need to save up for some 18 inch wheels and new 18" tires to match.

Although I am inclined to let it vibrate until I wear out these new tires. I know I can't wait that long. I'll just have to use a set of vibrating wheels for the winter only.

Expensive and beyond annoying. I had a set of new tires installed on these wheels not long ago, before the other tires were worn out, because I thought we had found a bad tire.

Brought it elsewhere and stripped the tires from the wheels and checked run-out again and found the bad wheel. The other 3 are on the edge of being bad enough to replace. Seems to get worse when the temp drops for some reason.

And I cannot complain to the shop that helped me with determining it was a tire and not the wheels. The shop that sold me 4 new tires. They have gone out of business after having been a part of this town forever. The Economy and Mis-Management brought him down.
Saw the Ex-Owner recently and he is just about homeless and all messed up. No help from him.

I also have the telltale mysterious Riviera shake,rattle&roll! I did the brakes first(new rotors & Napa premium pads). Next I had the stock rims and tires balanced. One of them was slightly bent so I bought 17" Lucerne chrome wheels and Bridgestone 235/55zr17 tires (all brand new). After all of this the car looks great and handles better but still has vibration mostly between 60&75 and worse during hard braking. I'm thinking that I will be replacing the trans mounts next because they are sloppy too! Getting this car back to new or better is costing me quite a bit of money and labor! Watch my hubs go out next with my luck lately. Still wouldn't trade her for anything though-I love my Riviera more than all of my other rides!

crlombardi69 wrote:

I also have the telltale mysterious Riviera shake,rattle&roll! I did the brakes first(new rotors & Napa premium pads). Next I had the stock rims and tires balanced. One of them was slightly bent so I bought 17" Lucerne chrome wheels and Bridgestone 235/55zr17 tires (all brand new). After all of this the car looks great and handles better but still has vibration mostly between 60&75 and worse during hard braking. I'm thinking that I will be replacing the trans mounts next because they are sloppy too! Getting this car back to new or better is costing me quite a bit of money and labor! Watch my hubs go out next with my luck lately. Still wouldn't trade her for anything though-I love my Riviera more than all of my other rides!

You just gave yourself a GIANT clue dude. Your problem is most likely somewhere in the front end. I would give the front suspension a good shake-down. You may have a worn out tie rod end or something. Also possible to have bad LRO on one of the hubs. That would explain the vibrations getting worse during braking.

I wasn't looking here for the solution I was just adding to the conversation about this common problem with riv's. My brakes were shot and I didn't like the stock wheels so it was a good excuse to get the ones I really wanted. Other than the trans mount it is very tight in the front end of my car. Inner and outer tie-rod ends are good,the alignment is dead on the number and just haven't had extra time to lift it up and get under the car to further investigate this issue. It's just my work car not that big of a problem yet to get to the top of my priority list yet.

crlombardi69 wrote:

I wasn't looking here for the solution I was just adding to the conversation about this common problem with riv's. My brakes were shot and I didn't like the stock wheels so it was a good excuse to get the ones I really wanted. Other than the trans mount it is very tight in the front end of my car. Inner and outer tie-rod ends are good,the alignment is dead on the number and just haven't had extra time to lift it up and get under the car to further investigate this issue. It's just my work car not that big of a problem yet to get to the top of my priority list yet.

Then I retract my diagnosis help, and apologize for ASSuming that you were looking for help

Rickw wrote:

madrivage wrote:

Well,new front hubs,new front struts,new rear trans mount,road force balancing ,pressure at 30psi,lugs hand tightened to 100ft lbs in a perfect star pattern...STILL VIBRATES AT 63-75 MPH!!! W T F????? I haven't changed the tires as of yet cause they still have a lot of meat left on them,but I'm running out of patience with this.Has anyone tried using DYNABEADS to clear up this issue??? http://www.dynabeads.net I'm willing to try anything at this point.

I have been down the same frustrating road and have determined with a dial indicator that I have a slightly bent wheel. Even though it all balances out on the machine, these cars are super sensitive to the wheels being out of true, just a little bit, for some reason.
Other cars are more tolerant and won't vibrate over such a small anomaly on one wheel. But this car does.
It shows up as a vibration on smooth roads between 60 and 80 mph and you feel it in the seat, floor and steering wheel to some degree. Very, Very friggin annoying.

I recall someone from GM research mentioning that the Riv suspension has a periodic oscillation at a certain frequency (that corresponds with the RPM of the road wheels) and *any* imbalance or misalignment gets amplified and can be felt. Althoug I have not tried it, I understand that the problem can be changed (not cured) using stiffer springs, but stiffer springs cause other problems along the line of "it does not ride like a buick, you can feel every pebble in the road" or some such.

Albertj

Sorry but it seemed to me that you were assuming that I don't have a clue about suspensions by the reply you sent back. I have read the thread beginning to end multiple times and had already "shook down" the front end when I replaced the brakes. Also if there was major wear on frt. Suspension parts it wouldn't be able to be aligned to factory specifications and stay that way. I know my way around a car too and was hoping to have an intelligent conversation about these issues a lot of riv owners have and do have not a guessing game. Sounded to me like you were assuming I don't know shit and you are the end all be all on riviera repairs. Thanks for telling me the basics that were already covered instead of engaging in more specific diagnosis! I apologize if I offended you I just expected better than that generalized reply like I was an idiot.

crlombardi69 wrote:

Sorry but it seemed to me that you were assuming that I don't have a clue about suspensions by the reply you sent back. I have read the thread beginning to end multiple times and had already "shook down" the front end when I replaced the brakes. Also if there was major wear on frt. Suspension parts it wouldn't be able to be aligned to factory specifications and stay that way. I know my way around a car too and was hoping to have an intelligent conversation about these issues a lot of riv owners have and do have not a guessing game. Sounded to me like you were assuming I don't know shit and you are the end all be all on riviera repairs. Thanks for telling me the basics that were already covered instead of engaging in more specific diagnosis! I apologize if I offended you I just expected better than that generalized reply like I was an idiot.

I didn't say you don't have a clue, did I? Haven't you ever had someone suggest something to you that you may have forgotten, and go DUH? All I did was suggest something. Most of us OBVIOUSLY have this problem, including myself. AND, at this point, it IS a guessing game. Think about it......
I'm sorry that you're a pro, and I offended YOU merely by suggesting something in a thread regarding a HOW-TO concern. Next time, you might want to say you've already tried this-and-that, and then you won't get some suggestions from people like me (Your original post doesn't say you weren't looking for a cure).

I love how you jumped on the ASSumption that I think you're inferior to me. Nobody said you don't know shit, and nobody assumed it. Re-read the posts carefully, and when you're ready to play nicely, you can come out of the corner....

Not claiming to know better than either of you guys, but here is my feeling based on reading your comments. I'm choosing to share this because I'm not involved (yet), hoping to diffuse the situation before it gets overheated.

To crlombardi69: whenever someone posts in our tech forums, the post usually falls into one of three categories - 1) you contribute helpful info, 2) you ask for troubleshooting help, or 3) a mix of contribution & asking for help. Your above post, imo, falls under #3. While you did share your experience with the issue, you also claimed the problem wasn't solved, and you went further to give us some of the reasons that could be causing it. The result was an open invitation for other members to offer assistance. You may not have intended it that way, but part of your post could be perceived as asking for help - that's how tech forums work.

To Abaddon: because you are an automotive mechanic, there oftentimes is an air of elitism in the way you deliver information in posts. Things can come off a bit matter-of-fact-ish, probably because you're just confidant in your knowledge of auto mechanics (I have the same problem, trying to work on it). And from your perspective as a professional, the advice you give should be received with a little appreciation - after all, it's free and you could be charging for this kind of info. It's understandable. We all like acknowledgment for the things we are good at.

This was simply a misunderstanding, because you guys were not communicating on the same level. After all, you don't know one another, and probably never communicated with each other before now. Chris didn't realize he had invited others to help with his problem. Scott, being first on the scene, tried to respond, not realizing his tone could be perceived as condescending.

Both of you were wrong, and both of you were right, and it doesn't much matter at this point. Let's shake hands, respect each others' intentions, and get back to talking about the issue, and how we might go about solving it. I think we can all agree that these cars didn't shake when they were brand new, and that balancing the tires doesn't always fix it. I know loose suspension contributes to the vibration, but not sure it's the only cause. What Albertj said about the resonant frequency makes a lot of sense to me. Changing the wheels/springs to shift vibrations into a different band could be key in calming the shimmy. It may explain how changing to aftermarket wheels has proven to be the end of my trouble. I'm not sure why it didn't work in Chris's case - maybe the Lucerne wheels are similar enough to our OEMs that they didn't have the same suppressing effect?

My riv developed the shimmy several months after I bought it and for the longest time it wouldn't go away. At first it would begin to shake at about 75-80 but as the problem got worse it started as low as between 62 and 65 mph and would get progressively worse as speed increased. Due to the severity of the shaking I couldn't exceed 75 mph for fear of losing control. By 75 mph the car would shake so badly that I could see it shaking the dashboard and steering wheel and it felt as if the tires were skipping or vibrating instead of rolling smoothly. Just a side not, this shaking would happen whether I was in gear or neutral and seemed to get slightly worse after filling up with gas. I tried several of the suggested remedies including an alignment, rebalancing the wheels, and rotating the tires and the only thing that helped at all was the tire rotation, tho it didn't go away fully but was reduced until the tires wore down a bit then it came back. I just had my rear shock replaced yesterday with a set of monroe ma822 which I bought of a member of this forum(thanks again Vinny for selling them to me) and lo and behold the shimmy is gone! I had the car at 75 today and while I could feel a tiny bit of occilation its definitely coming from the front of the car this time. I still need to replace the front struts yet so hopefully that will take care of it. My guess of what happened; at some point the rear shocks developed a small hole which caused the shimmy and as the shocks got worse so did the shimmy. When it got to the point that they were blown completely the shaking became too much for the worn front struts to control hence the unsafe feeling at high speeds. Now that the rear shocks are new I can pinpoint the remaining feeling of vibration as coming from the front, whereas before it was shaking so bad I couldn't tell where it was coming from. I know many members have replaced shocks and not felt any difference, I just wanted to post my findings. I will post an update if the shaking comes back or if new struts remove the remainder of it.

Thanks for sharing. If you've ever passed a car/truck on the road with a bad shock, you can see the wheel bouncing violently with every bump. The vibrations are not damped, but instead transfered into the body of the car.

I think your problem was a combination of bad wheel/tire balance and bad shocks. The shocks amplified the wheel vibration by a large amount, so when you replaced the shocks, it lessoned a bit. The remaining vibration is still likely a bent wheel or unbalanced tire. Just curious - how are your tires wearing, and when was your last wheel alignment?

I doubt it made a difference but I forgot to mention I also had the shock mounts replaced with quality Moog mounts. AA the tires are about 2 1/2 years old and seem to be wearing evenly with plenty of tread left. If I had the money I'd replace them anyway cause they are crappy goodyear integrity tires that the dealer I bought it from put on. Last alignment was about a year ago when the shimmy started moving from 75 down to lower speeds which didn't seem to help. I'm not doubting that's probably a part of the problem as we have large and numerous potholes in jersey. I'm gonna hold off on the alignment till I have the money to replace the struts and strut mounts which feel worn anyway now compared to the back, as that will require another alignment. While that's getting done I'll have my mechanic shake down the front end and see what else he finds but that won't likely be till after xmas.

I wouldn't get too discouraged. Yes, the shocks were bad (obviously lol), but most of us have a vibration that we can't get rid of at or around 70mph. My car has it, CjLombardi's car definitely has it. He even has aftermarket wheels, brand new brakes, etc......his vibration is worse than mine. It seems to disappear below 65mph and above 75mph. We'll figure it out. I know quite a few of us lookin for answers......

It's been discussed for years now to no avail....

I drove a '99 Aurora yesterday with the same issue, vibration at/around 72mph.....

looks like a hot thread.

I don't have a solid answer for anyone but dealt with it thrice on my 96. the 65-75 shimmy was remedied once with new tires, a year later it was remedied with new rotors and pads. the third time was happening when I sold the car.

your mileage, of course, may vary but this is how I dealt with it.

For me, aftermarket wheels cured the problem for the 6 months I had them on. The tires that came with the wheels were used, and are now bald, and still no vibration.

When I put the OEMs back on for winter last week (w/ almost new Firehawk WO tires, mounted & balanced), the vibration came back immediately. It's obvious what's wrong, imo.

I have also had a vibration since i bought the car about 5 years ago.
I started trying to troubleshoot the problem the old fashioned way, replaced 2 worn tires with matching tires and balanced and rotated everything. Seemed to minimize the vibration at 65 to 75 mph for a while, but it came back in a short amount of time. So I guess I never did minimize it, just wasn't driving much between 60 and 75 mph. Tried replacing all four shocks/struts and an alignment. No Relief.
Have since gone through that set of tires, actually had them replaced sooner than they needed thinking I could eliminate the problem with tires.
This was all before I even hit 100K miles on the car and have checked and triple checked all the joints and bushings and have had it on an alignment rack 3 times just to be sure , etc.
I have removed the rubber from the wheels and with dial indicators checked the runout of the wheels for lateral and radial runout. Did not see anything that would concern me.
I am at the point where I hate driving on the highway, as it removes any pleasure of driving the car at the speeds that are considered legal. 60 to 75. After 80 mph it seems to level out and gets smooth, but I am waiting for a ticket.
If I drive at 55 to 60 it is smooth but I cause traffic jam's and I hate driving at those speeds and I shouldn't be forced to with a Luxury car.
I am considering doing the irrational and start throwing parts at it that it doesn't need, like inner and outer tie-rod ends, new control arms with bushings and balljoints, new wheels, etc.
I can easily toss another 1,000 dollars at the car and still have the same problem.
If I didn't like the car too much, I'd sell it too.

Anybody want to buy a reasonably modified Riviera in very good condition that has not been beaten to death with a VERY ANNOYING highway vibration that happens on smooth roads. Especially recently paved roads.

Wheels are my next investment, I guess. I friggin tired of this problem.

Rick-If you throw any parts at it, I would start with tie rod ends. You can get them cheap and they are easy to replace. Did mine and the car cruises smoother now.

DEMonte1997 wrote:

Rick-If you throw any parts at it, I would start with tie rod ends. You can get them cheap and they are easy to replace. Did mine and the car cruises smoother now.

Smoother meaning better, but not perfect, correct.?