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Vibration after tire change

I changed all 4 tires on my Acura TSX after 60000 miles from Michelins to Firestone GT Hawk. Now I get vibration when driving over 60 mph. The steering shakes - not violently but it is there and I can feel the floor & pedals

shake too.

I took it back for rebalance and the Firestone mechanic said that it was out of balance by 0.5Oz. The vibration reappeared. Then the chief mechanic said it is my right ball joint. My car was fine until I changed the tires. Any advice / suggestions?

I want to go to Michelin Primacy MXV4 tires

Shaking in the floor and pedals often point to a rear tire problem and is this bad ball joint on the rear of the car?

A bad ball joint should definitely be replaced but the concern also would be this tire being .5 ounce out of balance. That’s a huge amount of imbalance and could point to someone not balancing the tires properly, wheel balancer out of calibration, a faulty tire, or even a tire that was not mounted correctly.

Whether your car has a bad ball joint I have no idea. You might give them another shot at balancing or ask if they would cover the cost to have the balance checked somewhere else.
Also keep in mind that Firestone and bad ball joints are pretty much synonymous with each other.

Thank you for your reply. This morning I got my tires replaced with the stock michelins - Pilot MXM4. These were great for me as they lasted 60000 miles. On top of it I think if the sidewall did not have a nail sticking into it I would have gone another 5-10k miles easily.

I checked the balance of the wheels before replacing and they were really bad. Here are the numbers, just as I suspected and you pointed out:

Front Right (planes inside/outside) : 0.5/1.25
Front Left: 1.0/1.5
Rear Right: 0.75/0.25
Rear Left: 0/0.75

I suspect that the new balancing machine installed at Firestone was not calibrated and hence the crazy unbalance - no wonder my car was shaking. I talked to Firestone reginal manager who has agreed to pay me back my money. It is unbelieveable that despite this proof Firestone still does not want to accept that it was their fault.
With the new tires in rain I went up to 70 mph and the vibration disappeared. One thing I learned from this is never to try to save a few dollars on cheap tires!

I will never go to Firestone again. I think they are clueless.

Congratulations on getting a fair reslution. Very few do.

I suspect either you’re right about the machine’s calibration or the techs there simply are not properly trained in its use.

Happy motoring.

Long Version:

http://www.barrystiretech.com/unifandbal.html

Short Version:

There is a tire property called “Uniformity”. Think “roundness” and you’ll not be far off the mark.

Once a tire has been balanced, it is balanced. But that doesn’t address the uniformity.

Since many tire busters don’t spend a lot of time trying to understand these sorts of things, they will continually try to re-balance tires in the hope that this is the problem.

But there are certain vehicles that seem overly sensitive to balance and uniformity - and the Acura TSX seems to be of them. Plus, certain parts of the country don’t get the freezing and thawing of the road surface that causes small bumps that obscure the vibration being caused by tire uniformity.

Put another way, long stretches of smooth roads tend to sensitize drivers to the rythmic vibrations caused by balance and uniformity that are normally disguised by the small road surface irregularities present in most road surfaces.

Seeing a lot of weight on a tire and rim assembly doesn’t mean the assembly was balanced improperly.

I understand your point. It is valid as the cheap Firestone tires potentially are not round - these were made in the 42nd week of 2009. What I did not mention above is that I got my tires changed at American Tire depot. The mechanic there gladly agreed to check the balance of the existing wheels before he replaced them and I wrote down the unbalance.

The uniformity does not completely explain why the vibration shows up suddenly at 60 mph (a resonance perhaps!) and disappears at 63mph and reappears at 65 & 70mph. The vibration at 60mph is the highest. I am a engineer and I work in this highly specialized area of rotordynamics. The simplest cause is the unbalance, althought un-uniformity, typically called at run-out in the technical field, does cause vibration. Vibration from run-out (out of round) is seen at all speeds.

Shendi,

Thanks for clearing up the point about the residual imbalance. That completely changes the diagnosis - and you are right! Those numbers should result in a vibration for pretty much any vehicle.

But perhaps you need to read this again:

http://www.barrystiretech.com/unifandbal.html

Short version:

Wheel end vibrations occur in the 50 to 70 mph range because of the natural resonance of the Spring-Mass-Damper system known as the suspension. This natural resonance is commonly called the “Wheel Hop Frequency”. It doesn’t matter if it is balance or uniformity driving the issue, that’s where it will show up the strongest.

After almost two weeks after changing to michelins I think I have another problem: my clutch pedal is vibrating (shaking at 65~70mph). On rough roads I can feel the floor shaking too - at any speed. Should I check the clutch or transmission. Does anyone think that the original vibrations could have misaligned the train and/or shaken the engine mounts out of place? Any help/suggestions would be great.

Also, my gas mileage improved a bit, but it is still not where it was before this whole rotten episode.