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Going With Michelin Primacy

2400 Views 11 Replies 6 Participants Last post by  Glock3540
Hello All,

I have a vibration problem at highway speeds (60mph+). When trying to diagnose what was causing the problem I checked to see at what mph the vibration started and ended. I changed lanes quickly, sped up and slowed down, up hills and down hills, put the car in neutral and coasted, etc with no discernable change in the vibration.

I have done the following trying to correct the problem:
Replaced both outer tie rod ends (pass. side was in poor shape). Moog
Replaced all 4 hubs (drivers side front had a little play). Timken
Replaced front lower ball joints (just to eliminate them being the problem). Moog
Replaced ALL sway bar bushings, front and rear. Moog and OEM
Replaced all 4 rotors. AC Delco
Replaced all brake pads. Top of the line Monroe Ceramic pads..
Replaced both suspension adj links.
Replaced front motor mount. OEM
Fabricated some torque mounts to limit engine movement.

Vibration still there.

Had my tires Hunter "Road Force Balanced". They found 2 slightly out of round rims. They had no lateral runout but were actually bent. Not too bad of a "bend" but I had them order 2 factory rims. They did another Road Force Balance to make sure the replacement rims were not bent also. They said my tires were OK.

Little Better but vibration still there.

Took off wheels and FANATICALLY cleaned all mating surfaces.
There is No rust, No Paint, No foreign objects of any kind (at least to be
seen with the naked eye) on any of the mating surfaces.

Reinstalled wheels and torqued in a star pattern in a three step torque
First 80lbs, then 90 lbs and finally 100 lbs of torque and then triple

Vibration still there.

The other "possibilities" for the vibration that I can think of are;
Possible bad CV joints (although no clicking or any other signs of a failing joints and all boots are in good shape with no leaks). I did notice when installing the new hubs, I noticed some "play" in the spline teeth on the cv axle where it enters the transmission/transaxle. The teeth did not look damaged or even worn but there was what I considered excessive play. I would expect there to be almost no discernable play or at least Very Little.
I have not replaced the CV axle assembly yet. I do not want chinese rebuilt CV joints, nor do I want OEM. After much research, I have contacted for info about complete assembly replacemet. No response from them yet, but I read their owner?, was involved in a small plane accident so it may be awhile before he gets back to work to answer my question (I pray he is going to be OK). MAYBE I have a slightly bent axle shaft and that is my vibration problem?
I have read that some believe the transmission/transaxle/differential has a defect in its design that may cause this vibration. Not sure about that one...
What do you guys think? Could it really be a differential pinion gear issue?

I have read that the front lower control arms might be part of the problem.
I have replaced my ball joints so I do not want to replace the entire lower arm that comes with the ball joint already installed. The Moog ball joints I installed are at least as good as OEM and I suspect better. I do know they have grease fittings;)
I wanted to replace the front and rear control arm bushings but for some reason GM designed them so you cannot replace them. Thanks GM.
I have only found one person that sells replacement bushings but they are poly. I do not want any Squeeky bushings! I have contacted Walton Manufacturing which I think makes very high quality bushings. He thought he had some bushings that would fit my car. I told him I think he was thinking of an earlier model Caddy, and after checking, he said I was correct. He said he was going to check into making some for me but has not got back with me yet. (I think if He would design and manufacture some front and rear bushings for the 2000-2005 Devilles, and made them reasonably priced, he would sell a bunch of them! None of us wants GM forcing us into purchasing an entire arm if we may need just bushings!)

I have read where at least one person thinks it is "air" caught in the power steering pump/lines. Doesn't sound like it could be a factor but who am I?
I cannot find the problem so maybe it is the windshield wipers for all I know!

One question that I do have is; I have measured my ride height on all 4 corners and the front 2 are within 1/8" of each other.
On the rear however, pass side is almost 1/2" lower than the drivers side.
Upon investigating this I realized I have never noticed the rear shocks air compressor running. Is this something that you can hear from inside the car?
I have spent many,many hours in the garage working on this car and I have never heard it. On my late fathers 97'? Deville, we could be sitting outside relaxing and you could hear the air compressor cutting on and off every once in awhile (he had a leaking shock).
I was planning on replacing the front struts and rear shocks with Gabriels but with only 44,000 miles I have not done this yet. Maybe I have some dryrot on the inside of the things but they look great on the outside. No visible damage of any kind. Maybe this is the reason the rear end hops a little sideways when hitting a pothole or road anomaly? It is disconcerting to be cruising down a straight, flat road at 40mph and hit a little pot hole and the rear end steps out like I would expect it to do if I hit a big patch of ice or something...

I have Continential Conti Touring tires on it right now and they have less than
1000 miles on them. I purchased them from an individual so I do not have any warranty as far as exchanging them but they did still have factory stickers on them and were absolutely brand new. I realize this is a relatively cheap tire and I am a Michelin Man (My father worked building tires and in the testing laboratory at Pirelli Amstrong tires for 30+ years. He was fanatical about vehicle tire ride (smooth ride, etc). He said they purchased and tested competitors tires and they were always impressed with Michelin tires. They were baffled how Michelin could make a tire with so tight of tolerances. He said Michelins were the best tire on the road.

So after this Extremely Long Post, I am breaking down and spending almost $1000.00 this Saturday on Michelin Primacy tires for my Caddy. I did extensive research when replacing tires on my wife's Accord (after 2 sets of "upper end" Bridgestone's that wore pretty well but rode like a bucket of bolts). I put Primacy's on her car and it transformed the vehicle. It rides Much Better now and she is very happy (so that makes me happy ;)).
I called Discount Tires and asked the rep if someone could ride with me out on the interstate so I could show him the vibration before purchasing and installing the new tires. They are great people and I am hoping for good results. I really give it a 50-50 chance the tires fix my vibration problem but at least I will eliminate the tires as the possible culprit.

I have replaced the water pump and thermostat and the new "redesigned" cover to fix a leak I had with the factory cover.
I replaced the plenum (just because I know this is a known possible problem with our cars). While I was replacing the plenum, I put on all new OEM intake gaskets/rings and cleaned the plenum as described in the tech tips here on this forum. Big Difference. I had a sticky accelerator pedal and this fixed that as well as made the car idle even smoother. I put Amsoil Synthetic oil and trans fluid in and this also made a difference. The trans shifts so smooth now it is almost inperceptible, LS Lexus smooth.

So now I have this pearl white beauty that purrs like a kitten and runs great.
It stops well and handles as well as expected for a car of it's type (except for the rear end step out that I think fixing the shock/compressor problem will fix).

I hope after these tires she will ride as smooth as she should. If not, I will do a few more things to the car to see if I can fix the vibration issue. If I cannot eliminate or at least make the vibration much less noticible, I will make this car a secondary road car only. I would be embarassed for someone to ride in my CADILLAC that shakes like a worn out Jeep at speed (this is an exaggertion but continued frustration with this issue is starting to aggravate me).

Thanks for letting me rant. I can be a very stubborn person when I think something can be worked out, so I hardly ever give up on anything.
I want So Badly to get rid of this vibration but to be perfectly honest, it is about to get the better of me. Very few times in my 35+ years of amateur wrench turning, have I seen something so elusive....
Blessings Everyone,
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I have read through hundreds of posts/threads here. The guys on this forum have been very helpful with their responses to my
questions and the tech tips section was especially helpful also.
I Really Like My Car, If it were not for this VIBRATION!
Thanks for the responses so far guys.
Yesterday I went to Discount Tires. I had one of their reps go out on the interstate with me as I described
all I had done trying to eliminate this vibration. As we got up to highway speeds he said "Oh Yea. I can feel it".
I had him touch the steering wheel and he shook his head. I then asked if he thought it was a tire issue.
He was hesitant and I told him "I'm not going to hold you to it" meaning, I was not going to hold him responsible
if I purchased new tires and it did not cure the problem.
He replied "You have replaced everything that I can think of that might be causing it".
I told him that it was my belief that even the Road Force Balance machine had to compromise.

My father told me that most tires are machine assisted but essentially hand made.
The tire builder had to measure off strips of rubber and cut them to size and place
them on various parts of the tire. He showed me on some tires that
occasionally you would find a tire that had a "dip" on the sidewall that was visible.
He showed me how the dip extended the entire height of the sidewall.
He told me that was a small mistake. The tire builder had
cut that strip of rubber for that particular tire a little short. He said it was not dangerous
but it did make the tire hard to balance.
He told me the little rubber "tits" that were on tires are actually for the excess rubber.
After the builder finished hand placing the strips on the tire it would go into another
machine that would pressure fill the tire with rubber in a mold and then it would be heated
to cure the tire. (It has been many years since he took me on a plant tour so I am going
by memory so please forgive me if I have steps mixed up a little).
He said the machines were calibrated to put just a tiny bit more rubber into the mold than
was necessary. This made sure there were no voids in the tires after curing.
I'm sure tire building had changed some since he worked at Pirelli but some tasks are still

I told the rep that I think all tires have MULTIPLE high points and low points as well
as heavy and lighter places on a given tire. The balancer does it's best to put the correlation
of the tire on the rim to give the best possible balance. He told me that is exactly correct.
After we got back, he had them Road Force Balance my Continental's one more time
to eliminate the possibility of a weight on a tire that had come off.
After balancing again, they said 3 of the tires were good and the fourth tire
was "off a little" but not very bad. He said "tires are shaped like eggs and it is hard to get them balanced"
(tongue in cheek;)).
I took the car out for another test drive by myself and the vibration was still there.
While I was out on this test drive (that was just for a few miles) A Lamborghini LP640 (he had these numbers
on his vanity license plate) passed me downshifting while slowing down. That car sounded amazing. I had the windows
up and quickly rolled them down and the exhaust note ,as he was blipping the throttle, gave me chill bumps.
I'm not sure if he had removed the factory mufflers or what, but it was as loud as the straight piped Mustangs (no cats but
did have Flowmasters) I used to own/race. Even though I was still a little disappointed the vibration was still there,
I could not help but smile when I pulled up next to the Lambo at the stoplight. And No, I did not try to race him. I was turning
right anyway!!! It was even more amazing in that the rep and I had just seen a Ferrari on the initial test drive
(it looked like a 599 GTB but I am not sure because it was passing us going the opposite direction by the time I noticed it).

I told the rep when I returned, to put the Michelin's on. He said he would not charge me again for the lifetime balance because
I had just purchased it for the Continental's just a few months ago. He also asked me what I was going to do with the Continental's.
(He had just measured the tread depth and said they were "new" tires. I told him I only had 1000 miles on them).
I told him to just throw them in the trunk if they would fit and I would try to sell them somehow. I had imagined I might get $100 for
them on Craigslist. He then asked if I wanted to trade them in. I asked how much he would give me for them (I figured maybe $20 each).
He said "The best I can do is $50 a tire". I said "Lets Do It!". I really think he gave me a pretty good trade in because of all the
trouble I have had with these tires. SO; No balance charge, trade in value, $70 rebate from Michelin (that ended yesterday),
adding in the road hazard warranty and my total was (including the rebate) $623.00! I was very happy.
Another tech that was walking by (they all knew me and my issues because I had been there several times in the past few weeks)
asked me what I decided to do. I told him I was going with the Michelins. He said "Yea, There is Michelin and Then There Is Everyone Else"
while using his hands to demonstrate how high Michelin was on a scale of height compared to all the other tires they sell.
I replied "I Know." The rep later told me that he could not rememer the last time they had a balance issue with a Michelin tire.

We had to wait a few minutes because they were so busy. It is amazing how many cars they have come in and have their tires replaced
in just the hour or so we were there each time in the past several weeks!
They pulled my car in the first bay directly in front of the big window where my wife and I were sitting watching the techs [(actually my wife
was reading her Kindle. My wife,back in the day, used to be a 1/4 mile drag racer around the time Muldowney was racing. She still holds the
track record at a local track or two but in now defunct racing catagories.D Gasser with a modified 67 Shelby GT500 and some sort of a dragster
at one time and also raced at Nashville Fairgrounds Racetrack with the circle track guys a little. She did all of this with her Ex husband...
Guys, let me tell you; for a girl...., She Can Drive!)]
As I was watching them dismount and then mount and balance my new tires, I noticed they were not indexing the tires and then rotating
them on the rim to compensate for high and low spots on the tires. I was concerned they were cutting corners and not really utilizing
all the benefits of the Hunter Road Force Balance machine. I waited to question them about it until after I observed them using a hand torque wrench and
properly torque my wheels in a star pattern. They did and actually doublechecked their torque by going over the lugs nuts again.

When the rep come out to me (he was actually the guy who did the balance), he said they balanced perfectly. He said the runout on the tires
were less than .001 and that was "nothing". He said that Michelin sidewalls are soft and they sometimes have a hard time seating the bead
of the tire on the rim. He said he aired them up to 80lbs or so to make sure they were seated and then back to to recommended spec.
I shook their hands and was excited to get out on the interstate to see if there was any improvement. I had previously told my wife I gave it
a 50-50 shot the vibration would be gone. I did expect the ride to be better and that would mask the vibration some but I did not think
the vibrations would be totally gone. On the side roads leading to the interstate I noticed a difference in the ride. Smoother and slightly more
"cushy". When I got out on the interstate I was watching the speedo with anticipation. 50...,55...,60...,65.... and then 70..............
Vibration greatly reduced!! YES!!!!! I would estimate 85 to 90% of the vibration is gone! On the way home I got it up to 90 and it was very smooth.
I think the most of the vibration that is left occurs around 70 mph (bummer) but it is now tolerable and I will not have to make my car a secondary road car.
My wife knows how disappointed I have been with the vibration issues over the past several months so she was kissing me on the cheek and saying
"I think it is a much improved ride and you should leave it alone". I told her that I was going to do a few more things and then I was going to quit.
(I want new shocks in the rear, new front struts and new cv axle assemblies to eliminate what I think could be causing the remaining vibration (unless
there really is a Factory design defect to begin with and this is as good as it gets).

Very long reply to my own thread but was excited to share the news with you guys (I had to wait until this afternoon because of a Wild Game Feast
at the Church last evening in which I was a cook and then teaching my middle school boys Sunday School class this morning).

Guys, I admit I have a bias. I base my bias on my experiences as well as others that I trust.
I do not know about the Vogue tires. They very well may be as good as Michelins.
But in my experience, whenever I have bought a different brand tire it was usually because of the
additional cost of the Michelins. There was usually someone at the store telling me "I think this tire
(insert brand name here) are just as good as the Michelins." In the long run I was Always sorry that I
compromised in buying the less expensive tire. In the past, sometimes it was because I was on a extremely
limited budget. Even so, I still longed for the better tire that I passed on because of price.
In the past 10 to 15 years I have purchased tires that were within just a few dollars of the Michelins because
I was at a store that I had traded with for years and the guy recommended these new Bridgestones or whatever.
My wife and I were always somewhat disappointed. 60,000 miles later I would buy some more tires and
would request Michelin's. The same guy told me (Hey I'm a forgiving guy) that he had some new Even Better
Bridgestones that were definately as good, in his opinion, as the Michelins. I told him I wanted Michelin's and
he said he would have to order them (Firestone/Bridgestone dealer. I changed to him years ago, after several tries with
Goodyear tires. I wanted to purchase American tires but have horror stories to tell you about my experiences
with the Goodyears I had. Now I am a loyal Discount Tires customer. They seem to have much less brand bias,at
least to me).
He called and tried his best to sell me the Bridgestones so I ended up going to Discount. The only gripe
I have with Discount is they do not have alignment machines. I like taking care of my alignment when we have our tires balanced
and rotated (that we do religiously every 5000 miles) and alignment every 6 months to a year. So I did buy a lifetime
alignment from the Bridgestone/Firestone dealer for $229.00! I thought this was kind of high but I guess after the first
few balances it will pay for itself.

So lumping all other tires together in this statement; "There is Michelin and then There Is Everyone Else".
Pony up the extra cash and your Caddy Will Thank You.
(BTW; I went with the Primacies instead of the Hydroedge because I suspected, and Discount Tires confirmed,
that the Hydro uses a harder compound rubber to get that 90,000 mile warranty so it has a slightly harsher ride.
I have a 60,000 mile warranty and I have got 80,000 to 90,000 with Michelins in the past (on various vehicles)
so I feel confident I will meet and exceed 60,000 on these tires, if I keep the car that long.

Guys, Thank You for the Responses and I hope that my experiences will help someone
and I'm Not Giving Up Yet on that last 10 to 15% of the vibration that is left!

Blessings Everyone,
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Sorry Sub,
Thanks for letting me talk. You and Ranger have been very helpful in helping me sort out my car issues.
I always look foward to the threads that you both reply to.
You are always informative, direct and courteous. Admirable character qualities.

Blessings, Brian
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