This car is driving me insane!

[Vetteguy]

I would still suspect that you have one or more bent rims. I know that you indicated the the rims checked out ok. I had bent rims on the passenger side of a 2009 Corvette ZR1. I was finally correctly diagnosed. You must use a dial indicator on the turning wheel to correctly check it.

 

[7Andrei7]

I would still suspect that you have one or more bent rims.

I am afraid you are right but it must be something that can only be seen with the tires off because I had all mechanics check the rims, saying that I'm willing to pay to have them fixed and all said they're fine. I'm assuming they would have wanted the extra work & cash?

 

[RogueIV]

I am afraid you are right but it must be something that can only be seen with the tires off because I had all mechanics check the rims, saying that I'm willing to pay to have them fixed and all said they're fine. I'm assuming they would have wanted the extra work & cash?

Wheel repair is a specialist thing and is likely outsourced. Probably not something they make a whole lot of money on.

 

[RM7]

Ok, so I went to this new shop and, as expected, one of the wheels did have an excessive road force detected.

The technician said it's the tire that is to blame. Even though I really pushed him to take the tire off and check the rim properly he assured me that it's the tire. A new Michelin tire... very disappointing.
He managed to get it repositioned on the rim, from the second attempt, in such a way that there was no more warning on the road force machine. The wheel was mounted on the rear.

They rebalanced all 4 wheels and I'd say it's now 99% smooth at 87mph. I am already super sensitive because of this whole nightmare so it seems like I feel every single shit and probably even imagine some.
The best thing is that vibrations don't increase even if I take it up to 120mph, which I did briefly, just for a test. I normally never exceed 95mph, in short bursts, to overtake someone.

I was thinking afterwards about next winter, when the bad tire will have to be moved to the front. So I called Michelin and they said I can take it to them in spring to have it checked out. If it turns out to be out of spec, they will replace it. If that is the case I'll probably need to buy a new one as well to pair it but at least there will be no vibrations.

Thank you all for your inputs! And thank you @stoopid for teaching me about road force. This is where I'll do everything from now on.

PS: If an admin could change the name of the topic to something less dramatic, maybe it will be of use to others in the future.
Perhaps: Successfully balancing your wheels in less than 7 attempts.

I bought some cheap chinese tires for an SUV I had recently and I was never able to get them balanced, same thing, kept trying different shops and places. It was definitely the tires, as I had winter tires that rolled perfectly on it. It's just gotta be a manufacturing defect as far as the tire.

 

[Stan]

What is the size of the winter tyres you used?
In our region ( i am in Bulgaria ) tire quality is a problem across all brands, no matter premium or value. Had similar issues with Continental Premium Contact 6 and the only way to balance these was on a Hunter ( Road force ) machine with a qualified specialist, as not every mechanic know how to use this with its full potential. " of my tires had excessive kg ( one had 7kg , the other had 11kg, all 4 bought brand new. Next set gonna be a cheap Chinese brand for a change.

 

[7Andrei7]

@Stan I don't believe there is any difference in tires that come from the same factory. Sorting them in separate quality standards would be a nightmare and more expensive than to make them all the same.
In my case, the tires come from the Slovakia plant and yes, I do agree they might be to blame as well. Or at least one of them. But this would be the case no matter where Michelin ships the Slovakia made tires.

 

[7Andrei7]

The plot thickens!
I was still unhappy with the small vibrations (not imagining it) and went to also check the rims. Forced the shop to take the tires off and check them and, surprise, 2 of them were slightly bent.
They were fixed BUT I still have vibrations.
Then they suggested to change the centering rings because they had a little play. I ordered new ones (67.1mm to 73.1mm) and here comes the big surprise.
The rings fit super snug on both rear hubs (bearings) but they wobble around on the front ones.
Tried all rings (new and old) and exactly the same. They can be slightly moved up down and are very easy to rotate and remove from the front hubs but super fit on the rear.
The vibrations/oscilations always are in the steering.
What do you think? I am looking for a precision tool to measure the hubs front and back.
This could explain why I had all these problems from the very beginning but how could this happen? Can a .x mm influence so much?

 

[7Andrei7]

Or is this just the copper spray which is almost gone on the front?
I am so lost..

 

[MerlintheMad]

Wow, never heard of such a thing before. That should be easy to remedy. The whole point is to get the wheel on centered: if the hub ring doesn't have any play when putting the wheel on, it should be a slam-dunk to get the wheel on centered. So, put a layer of tape on the hub, that way the ring will be snug to take the wheel. Just a suggestion.

Use calipers to measure.

 

[7Andrei7]

This was still not fixed..
In the meantime I got 2 new replacement tires but nothing changed.. either they replaced the wrong tires or it's not the tires.
Ordered aluminum centring rings... will see if they make a difference.
And today the car is at the dealer to get a new torque converter (for a different problem) and all engine&transmission mounts checked/replaced. Plus they will check/replace any bad bushings.
Will see if I manage to get this car back to a smooth ride because at the moment everything shudders and vibrates. And I find myself looking for new cars online...

 

[D.J.]

I am looking for a precision tool to measure the hubs front and back.

Absolutely any bog standard caliper would be more than accurate enough

Wow, never heard of such a thing before. That should be easy to remedy. The whole point is to get the wheel on centered: if the hub ring doesn't have any play when putting the wheel on, it should be a slam-dunk to get the wheel on centered. So, put a layer of tape on the hub, that way the ring will be snug to take the wheel. Just a suggestion.

Use calipers to measure.

I would do this. There should not be any play at all.

 

[7Andrei7]

Ok, this is a really good week for my car.
After replacing my torque converter, the dealer confirmed there are no other things wrong with it that could cause vibrations (except the wheels).
Just by replacing the converter I could feel a significant decrease in high speed vibrations.

Today I went to the tire shop where I had bought my tires (it's 120km away). At this point I had the 2 new tires on the front (bought last week) and the 2 one-month old tires on the rear (from the first set). They made a switch between the axels and used a new set of centring rings which fit VERY snug. You had to properly push them over the hub.

Went for a drive and this change did not fix it and in fact the vibration in the steering wheel increased significantly.
So then, they decided to put 2 brand-new tires on the front and kept the 2 new (one-week) tires on the rear. This FINALLY fixed all the vibrations !!!

The sum-up is I paid for 6 tires (out of 8 received) and now have 4 new ones on the car. 2 of the first set were already accepted by Michelin. I'll have to see (in January) if they will accept the other 2 back and reimburse me. That would be ideal.
It's clear that there was a mix of one or more bad tires, slightly bent rims, slightly loose centring rings and bad torque converter.

I spent all in all (without tires) about 350 EUR on all this shit
BUT
I finally have a vibration free car. At 100.000 km it really drives like new. Took it up (briefly) to 200km/h and it's rock solid. FINALLLYYYYYYY!!!!!!

 

[MerlintheMad]

Happy, happy, Joy, joy!! Like a bad relationship that suddenly turns into a romance, now you can Autobahn the heck out of your machine. When I pushed to 155 MPH (three months into my Stinger ownership), I had great respect for the hype that this is a true performance GT: it was as solid and smooth as at freeway speeds. But I had no appreciation for the fact that my particular vehicle was blessed with properly balanced tires, wheels and everything else in smooth working order: I just took it for granted. After following your saga, in retrospect I can only send a thankyou heavenward that my car is a completely satisfying ride: it could easily enough be otherwise. May you now love your car with complete abandon.

 

[7Andrei7]

Bad news, vibrations are slowly returning. I notice them especially when the road surface is super new and smooth. There is a very clear vibration (fast oscillation) that cat be felt in the whole car and increases with speed. It starts as low as 65mph.
There is also a significant increase in this vibration when I apply the brakes. If I quickly lift my foot off the brake pedal the vibration stays the same in type but diminishes a lot in intensity. So I don't believe it's caused by the rotors (which are fairly new).
I also don't believe it's the tires or wheel imbalance. It's not fast enough somehow.. don't know how to explain. Plus I've been switching tires like socks, as you know if you've read the topic.
My only idea is now that it's caused by something suspension related. Either ball joints or bushings or something there.
So, a riddle:
What causes a vibration on very smooth roads but not on slightly worn roads
and
Why does vibration increases under load (linear with speed increase) and when brake pressure is applied
but sometimes it does not vibrate at all.

 

[D.J.]

massively warped rotors - or massive cementite buildup on the rotors.

You using OEM brake pads?

 

[Ohiocruiser]

Wheel bearings?

 

[0Rock]

I have the same problem and it has to be brakes. I am planning to switch out both rotor and pads on all four soon with an after market parts. Hopefully that will fix the problem.

 

[MerlintheMad]

I have the same problem and it has to be brakes. I am planning to switch out both rotor and pads on all four soon with an after market parts. Hopefully that will fix the problem.

How can @7Andrei7 's problem be brakes when he is not on the brakes? Applying brakes makes it worse, not caused by the brakes (as I read what Andrei said).

 

[D.J.]

Bad news, vibrations are slowly returning. I notice them especially when the road surface is super new and smooth. There is a very clear vibration (fast oscillation) that cat be felt in the whole car and increases with speed. It starts as low as 65mph.
There is also a significant increase in this vibration when I apply the brakes. If I quickly lift my foot off the brake pedal the vibration stays the same in type but diminishes a lot in intensity. So I don't believe it's caused by the rotors (which are fairly new).
I also don't believe it's the tires or wheel imbalance. It's not fast enough somehow.. don't know how to explain. Plus I've been switching tires like socks, as you know if you've read the topic.
My only idea is now that it's caused by something suspension related. Either ball joints or bushings or something there.
So, a riddle:
What causes a vibration on very smooth roads but not on slightly worn roads
and
Why does vibration increases under load (linear with speed increase) and when brake pressure is applied
but sometimes it does not vibrate at all.

This vibration occurs when accelerating? Coasting? Braking?

All the above?

 

[7Andrei7]

Acceleration or coasting does not change anything.
Only difference is made by speed increase (vibration intensity grows proportional) and by braking (higher pressure generates more intense vibration).
It can’t be the brakes as the vibration is present without braking. And, if the road surface is a little rough/wobbly then vibration disappears both while driving and under braking.
Also, I changed rotors and pads less than 10k km ago, because of vibration under braking. That vibration was very different and only at very specific speeds.

@Ohiocruiser how can those be diagnosed?

I’ve had Kia look into it last time but they said all was fine and it must be the wheels. Could also be they don’t want to find anything as it might make them responsible‍…