Vibration / Shimmy at Cruising Speed

AA wrote:

Quote :

Are we supposed to replace our axles after X miles as preventive maintenance?

No, shouldn't need to. Mine are both original at 262k miles. Troubleshooting a noise, I once replaced the passenger side with a 30k mile used OEM axle. It changed absolutely nothing, so I knew it was the hub. I took the "new" axle back out and reinstalled my old one with over 200k miles on it.

(proven 200k mile axle > unknown 30k mile axle)

These axles are stout. If you manage to break one, you know something's really wrong. Either grease is gone from the boot, it got thrown into park while rolling, or someone's doing neutral drops.

Or, you just got a bad one from the factory - it happens.

whats a neutral drop?

so its supposed to emulate a clutch drop? impressive.

Yeah, instead of replacing the clutch, we get to replace hard parts in the trans, maybe the diff and CV joints, too. TQ converter if you're lucky!

Did you know the grease in the axle boot is GREEN!?

Quote :

New axle installed!
wow! vibrations are gone! Drivers side feels GREAT at cruise speed now!

im wondering if I replace the passengers side if I will achieve EVEN BETTER ride quality!

I think I got some lost power back too!

Are you saying that only the driver side of your car stopped shaking?

AA wrote:

Quote :

New axle installed!
wow! vibrations are gone! Drivers side feels GREAT at cruise speed now!

im wondering if I replace the passengers side if I will achieve EVEN BETTER ride quality!

I think I got some lost power back too!

Are you saying that only the driver side of your car stopped shaking?

Correct.

Now my vibes are minimal but are only coming from the passenger side!

I am satisfied with how it is now. HUGE improvement, but I am always seeking perfection. ya know?

Well you're better at pinpointing chassis vibration than I am!

You forgot to mention the vibration only occurred when you were accelerating. That's how you can tell a bad CV joint. Otherwise, a bad CV will make a clicking sound when you are turning or clunking when changing from P-R-D. The axle itself shouldn't ever go out of balance or fail.

It sounds to me like your CV joint was bad because of the torn boot. You fixed it, but the vibration that was there before is still there, because it had nothing to do with the axle. Could it be coming from the front rather than the right side?

AA wrote:

It sounds to me like your CV joint was bad because of the torn boot. You fixed it, but the vibration that was there before is still there, because it had nothing to do with the axle. Could it be coming from the front rather than the right side?

The new axle alleviated 96% of my vibrations. I only had vibrations at cruise speed. The minor stuff I hear/feel now is coming from the front passenger side.

Have noticed some vibration around 70mph on that right front as well. Could be the tires though as they are used of unknown quality, so I'll be changing them soon anyway. But I did rotate them and the vibration remained.

But I also recall the following thread (around page 10), so wonder if this also could be a bad CV/axle combo:

https://rivperformance.editboard.com/t9541p150-charlie-robinson-s-99-riv


..... I don't see it in that thread, but I thought Charlie (or maybe someone else) had some vibration around 70Mph and replacing the axle fixed it. So I wonder if both my symptoms of noise and vibration are related and may indicate a worn CV?

If so, how would one check other than just replacing it of course?

If the tropical storm doesn't drown us, I'll pull the wheel this weekend and also have a look at the other suggestions.

Al

AA wrote:

Quote :

Robe is right, if Buick wanted "that boulevard ride" soft bushings & mounts is one way to get it but from a value engineering and lifecycle cost perspective is bad for the customer, and is still a flaw IMHO in GM engineering. It does not save money really, it just takes what could be 1-time costs in design and pushes them into recurring costs later.

True, but that's why we replace these parts with (hopefully) more robust parts when they wear out. The OEM struts were junk, but each set of KYB struts & mounts I've replaced have gone 100k miles with no apparent degradation. I'm more than happy with this level of durability and performance. That being said, I never had vibration resulting from loose OEM struts. It was tires & wheel balance causing the issue.

Bushings and suspension can magnify the vibration, but the source usually comes from imbalanced rotating parts (tires, wheels, rotors, hubs, axles, flexplate, etc). If you fix the source(s) of the vibration, you'll need to do less covering up with bushings and suspension parts replacement, IMO. I'll never forget going through the process of replacing the struts, mounts, tie rod ends, control arm bushings, ball joints, STB, etc. Each time things got a little better, but it didnt go away. Switched to new wheels and tires - shimmy completely gone. For what it's worth, my rear suspension is completely stock except for shocks and sway bar.

Actually you're right in that the source of shimmy/vibration is always the moving or rotating parts. Bad bushings will allow trivial vibrations to become a PITA. It definitely is best to get perfect balance in the rotating parts, no matter what on the bushings.

Hey guys, I've been getting some vibration between 60-75 mph or so for a little while now. My buddy and I tried to diagnose the problem today and think I might have to road force balance the tires, meaning running them all through the apparatus, comparing variation numbers, then rotating a tire or tires around rims to compensate. Albert, I think that is what you posted about very early in this thread (I only looked at the first few pages of the thread here) with the Hunter balancer, which, oddly enough, is actually what my buddy thought was necessary.

Everything else looked and seemed to be okay... tie rod ends were replaced recently along with all new rotors, new pads, new struts and new shocks within the past 12 months but the wheels were aligned, balanced and then rebalanced within a year. Just not road force balanced  Btw also learned what a DOT # on a tire shows you and realized that one of my tires was made in 04, the other 3 in 2011!  

Do you guys think a road force balance would help? I just want this yacht to sail smooth!

I think the '04 tire needs to go, regardless of whether or not it's causing the vibration. Maybe you'll get lucky and the problem will go away.

My shimmy went away when I got new tires, braking shutter fixed when I put new front pads on.

 Thanks guys... I have an appointment to get the tires road force tested on Fri. Hoping the test shows that the '04 tire needs to be replaced so I don't have any more excuses not to do it

What I meant about replacing the '04 tire - its age is the test. Any 9-year-old tire MUST be replaced, imo. It automatically fails for that reason, whether it's causing the vibration or not!

Lol AA that's the kind of kick in the ass I need. I'm just amazed that the tread is still pretty good, it's just a little dry rotted

You caught it in time. It's probably fine until you get a new one. What you don't want is a 9+ year-old tire rolling around on the car for another year or six. This is how spontaneous failures can happen. There have been several cases of blow-outs causing loss control out of the blue. Like my friend in the Navy likes to say: "Don't Be That Guy!"

Don't feel bad, it's entirely possible that I was on original tires until last friday. They were fine, but they did vibrate. 75% of it went away when I got the new ones.

Road force balancing is just a fancy name for a way to use less wheel weights and suck your money away. It does not correct for an out of round rim or tire. There are some people who swear by it though.

When I put a wheel that's hard to balance on my balancer, I spin it and watch the edge of the rim for movement. Also watch the tire surface for rises and dips. Make sure you are comparing to a good fixed point and not reacting to optical illusions.

Many tires just have a lot of out-of-round, or possibly a shifted belt. If there is enough sidewall to cushion it you don't always notice how out-of-round they are.

I've complained of shimmy before up at 65-70mph before. Well I went to get these suckers rotated and balanced and huge shock. One tire has a different tread than the other three. Ever so slightly, but its the 'same' tire (regatta 2) but not only that, the one that's different is from '09 and the other three are from '02. Ugh...time to spend more money

I've had really good results and pleased customers with the Yokohama avid TRZ lately. Good all-around tire and very nice ride.

Hey Deek,

Thanks for the response. My mechanic friend told me about road force balancing and said just getting the diagnostic readout/printout and seeing what tire(s) have high variance should say plenty. Actually going through with the full procedure (rotating tire around rim, etc.) is another story and I personally would only have someone do that if the tire is anything other than my very old one. If the old one is the only problem, it'll be the only one replaced / balanced / etc. If I had my own balancer I'd do what you described lol, but alas...

It's nice and pricey though that's for sure! Btw, I ride on Michelin Symmetry tires and have for the life of the car. They've treated me well up until now. Evan, that sucks about your tires! Sounds like if those 3 are from 02 it's probably time to bite the bullet  

Update: Got the road force test done, looked at printouts from the test and noticed the oldest tire (the one from 04) had about 40lb road force variation. After rotating the tire around the rim to try to eliminate variation, the test was done again and we got 32lb variation. Both numbers were pretty high compared to other tire variations (10-12lbs for the others) so I decided to just replace the tire.

Drove the car yesterday and today and vibration is all but gone  It's seriously been years since this car has run so damn smooth.

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).