The shakes..

[Jan Olsson]

I've had problems with some shaking for a while now. It's most apparent around 75 mph. I know that the road force balance process is the right way to go, but here in Sweden there aren’t a lot of places to go to if you want the tires road force balanced.

The Badyears were thrown away in favour for Michelin Pilots. It's much better now, but it is still evident.

The main thing that concerns me is that sometimes they seem just perfect and sometimes I have the shakes. I was thinking that it would appear all the time and not on different occasions.

This morning for instance I could feel shakes when slowly accelerating and decelerating. This evening the car felt as new...

My old badyears behaved just the same, just worse...

I’m thinking about bad cv-joints, tie-rod ends etc. I do have some play in the tie-rod.

Anyone experienced anything similar?

[JohnnyG]

The symptoms you are feeling are CLASSIC rfb problems in these cars. Yes, I've had experience with it, and the RFB thing was EXACTLY as you describe. Not really sure where it's coming from, ability to "rotate" around the car etc. etc.

In my 99 STS I used the passenger seat seatback, and the secondary sunvisor as a visual aid. Road surfaces can cause a LOT of "false positives" for percieved vibrations, so you need to rule them out. Using the two visual methods I just told you about will reveal constant, repetitive, ocillations originating in the suspension or tires.

This DOES NOT rule out other mechanical problems, but get the CV joints and brake rotors checked out as best you can, but DON'T throw a lot of money at those items.

My money, on issues EXACTLY like this, is on the tires, and the wheels, which are mutually exclusive.

[Bruce Nunnally]

The Hunter Road Force Balancer distributor in Sweden is:

SWEDEN

BILMATERIEL AB (BIMA)

RAVEBERGSVAGEN ANGERED

S405 31

GOTEBORG

SWEDEN

Tel: +46-31-325-0700

Fax: +46-31-325-1611

info@bima.se;hlihv@volvocars.com

www.bima.se

So you might ask them where a convenient location to you is.

[bgain99]

The Hunter Road Force Balancer distributor in Sweden is:

SWEDEN

BILMATERIEL AB (BIMA)

RAVEBERGSVAGEN ANGERED

S405 31

GOTEBORG

SWEDEN

Tel: +46-31-325-0700

Fax: +46-31-325-1611

info@bima.se;hlihv@volvocars.com

www.bima.se

So you might ask them where a convenient location to you is.

[bgain99]

I feel your pain..my 02 Deville has shaken every since I have had it, bought as program car. Seems worse when car is pulling. Can't tell you the number of times have had it aligned, balanced, new tires, etc etc. Have not tried road balance yet as tires at end of life and wife drives car, and doesn't complain, lol.

Yesterday had car in for tuneup and brake check (previous GM rotors defective and replaced at 6000 mi) as getting rotor shimmy again wiht 17000 mi on rotors..and I was told my tie rod ends are loose and need replaced. Then another call saying can't get it aligned, and need to 'grind strut down' to get it fixed, as now if they align the front, the rear is out and vice versa?

Very interested to see if this fixes the problem, although I will be very disillusioned if loose tie rod ends have been causing this problem since 25000 mi and no other mechanics noticed it..

Used to fly/commute with engineers from Firestone, they said plants get best tires, also when the plants install tires on new cars, there is a balance mark on rim and tire, and they match those up for that new car ride. But haven't found a tire shop yet that knows about that.

On another note, had a Dodge 4WD pickup once that shimmied intermittently, it was finally determined to be the drive shaft out of balance..dealer weighted shaft, it helped some. Wondering if something like this is problem on this car..have checked motor mounts etc, as had that problem once on another car.

[jking220]

Dont rule out the tie rod ends. I know how important RFB is on these cars, but I have a tie rod end that I need to replace (waiting for new part since I was sent a trunk net instead) and now it is very evident what is wrong since it is so worn, but when it started, I thought it needed RFB. I finally started looking at the tie rod ends and ball joints when I started hearing a "clunking" while I backed out of my parents gravel driveway. You shouldnt feel any play between the tie rod and the front knuckle.

Also, how are your motor mounts? My dads 99 STS had a highway shake that we thought was from the tires, but it totally went away once we installed a new motor mount.

[Jan Olsson]

Dont rule out the tie rod ends. I know how important RFB is on these cars, but I have a tie rod end that I need to replace (waiting for new part since I was sent a trunk net instead) and now it is very evident what is wrong since it is so worn, but when it started, I thought it needed RFB. I finally started looking at the tie rod ends and ball joints when I started hearing a "clunking" while I backed out of my parents gravel driveway. You shouldnt feel any play between the tie rod and the front knuckle.

Also, how are your motor mounts? My dads 99 STS had a highway shake that we thought was from the tires, but it totally went away once we installed a new motor mount.

I've changed the front engine mount cause it went bad last year. I'll look into a road force balance at first. My brake pads are worn and the front rotors are developing cracks so I'm planning on checking the front suspension for excessive play once more at the same time I replace the pads and rotors.

[Jan Olsson]

The Hunter Road Force Balancer distributor in Sweden is:

SWEDEN

BILMATERIEL AB (BIMA)

RAVEBERGSVAGEN ANGERED

S405 31

GOTEBORG

SWEDEN

Tel: +46-31-325-0700

Fax: +46-31-325-1611

info@bima.se;hlihv@volvocars.com

www.bima.se

So you might ask them where a convenient location to you is.

Thanks Bruce!

It's ironic that Volvo sells the hunters here in Sweden. I'm somewhat reluctant about visiting a Volvo dealer

[Texas Jim]

Thanks Bruce!

It's ironic that Volvo sells the hunters here in Sweden. I'm somewhat reluctant about visiting a Volvo dealer

Jan,

If you go to the Volvo dealer... they can see what a REAL CAR is like and get jealous.

[Ranger]

Used to fly/commute with engineers from Firestone, they said plants get best tires,

That confirms what Logan has said. Plants get the best, dealers get the next best. Then come the factory stores and then Discount Tire and such. I will definitely look into dealers prices for my next set.

[Texas Jim]

Used to fly/commute with engineers from Firestone, they said plants get best tires,

That confirms what Logan has said. Plants get the best, dealers get the next best. Then come the factory stores and then Discount Tire and such. I will definitely look into dealers prices for my next set.

That makes two of us.

I was glad to learn that. I didn't know it till Logan psted the info the other day.

I will be getting new ones after my Labor Day Road Trip to Montana and Idaho.

[Logan]

1- Sure, the best tires go to the auto plants.

2- Talked to a factory tire room guy yesterday (outside supplier). They have a Hunter there on the plant floor, but only for diaganostics. The factory balance is done with a $1.5 million equipment and pre-screened tires.

*Anyone want to guess how they get air into the tires? Hint...they do not use the tire valves.

Figure factory production is: 4 good tires, mounted, excellent balance, with correct air pressure per minute.

Recently drove one our new products on the highway. My first comment was "So that's what 4 good tires feels like."

3- When Olsson says the vibration 'moves' around. I think he is describing 'phase in phase out'. A out of balance tire you will feel every rotation. You can have a balanced tire, but if its a bad tire, you will feel 2-3 bad tires phase in and out. So in one 1/4 mile the car is pretty smooth, but then you feel the tires start to match up again and create a more severe vibration in the next 1/4 mile. This cycle repeats and repeats. Smooth, vibe, smooth,vibe, etc.

4- Road condtions. Like the the highway I-65 I drive. Lots of national interstate semi traffic. Hot summer blacktop. You can see the pattern left by the trucks. Your going to feel some of that.

5- IMO, tire are good for about 25K. One time around the earth, by then you have hit enough potholes and railroad tracks the tires have to bad.

6- IMO, wheels are good for about 125K. 5 times around the earth, by then you have hit enough potholes and railroad tracks the wheels have to be bad.

7- Any rotating object will have 'some' vibration.

Case in point. My car, used eBay DTS wheels, $67 Tire Rack tires. Yeah, she's starting to get choppy again..But...not nearly as bad as that GTO test drive I mentioned earlier.

Called local Cadillac dealer, I know the guy at the parts counter, a RFB screened Michelin 235-55-17 is $220 each installed plus tax. Ok. 4 tires = $1000 with TN tax.

I know I have 2 rear wheels...not bent but they are not new. Sprung is the word I use. Could send them off to be repaired, about $125 each. Hmmm. I really dont want to put a great tire on suspect rim.

*Think in my case. I found a better deal.

Found a guy on eBay scrapping out 3-4 DTS's.

I bought 4, 2007 chrome DTS wheels with factory mounted and balanced tires, with 15 miles on them on eBay. The other car had 11 miles on it. The cars are being scrapped out for 'transit damage.'

So the 4 wheels AND tires shipped were $1025. I can sell my old ones on eBay. Here is the auction for the 11 mile set. I bought the 15 mile set.

<a href="http://cgi.ebay.com/ebaymotors/ws/eBayISAP...em=220269589638" target="_blank">http://cgi.ebay.com/ebaymotors/ws/eBayISAP...em=220269589638</a>

So, what is 'transit damage.' I found a picture on one of his front clip auctions. This is not the car my tires are from. But the 2 other looked exactly the same. Tires and wheels look fine...

Kids breaking windows. Detroit area. Water gets in..you can't fix that on a Cadillac. Scrap em' out.

Anyway, still waiting on these 15 mile DTS chrome wheels to get here. Will report back. We'll see.

Be sure to look at the guys eBay item for sale. Search 'Cadillac'. Tons of new steering wheels and engines and transmissions etc. Has excellent feedback.

[Ranger]

Called local Cadillac dealer, I know the guy at the parts counter, a RFB screened Michelin 235-55-17 is $220 each installed plus tax. Ok. 4 tires = $1000 with TN tax.

That would rule them out for me. If they won't at least match my best price, they can keep them.

Be sure to look at the guys eBay item for sale. Search 'Cadillac'. Tons of new steering wheels and engines and transmissions etc. Has excellent feedback.

Didn't notice any consoles did you (I'm at work and Ebay is blocked)?

[JohnnyG]

*Anyone want to guess how they get air into the tires? Hint...they do not use the tire valves.

Figure factory production is: 4 good tires, mounted, excellent balance, with correct air pressure per minute.

Recently drove one our new products on the highway. My first comment was "So that's what 4 good tires feels like."

3- When Olsson says the vibration 'moves' around. I think he is describing 'phase in phase out'. A out of balance tire you will feel every rotation. You can have a balanced tire, but if its a bad tire, you will feel 2-3 bad tires phase in and out. So in one 1/4 mile the car is pretty smooth, but then you feel the tires start to match up again and create a more severe vibration in the next 1/4 mile. This cycle repeats and repeats. Smooth, vibe, smooth,vibe, etc.

Yes, I'll bite. They put something in the tire that releases the exact amount of gas ("air") when it is ignited or dampened, in a very short time. I'd liken it to an explosion, much like an air bag going off. How close am I?

OK, that guess is pretty stupid. How about this: The tires are mounted in a room that is under pressure. When the tires are moved to a room at normal atmospheric pressure, guess what, they're inflated! Now I like that one better.

On item #3. That's probably the best analysis of the problem I have seen to date. And I feel that is EXACTLY what happens on these cars. This leads to a TON of issues all by itself. A driver gets his new tires and "Yeah, pretty good, finally fixed" Then he goes on a long trip, the tires get really warm, the sidewalls get to flexing real nice, the ride gets real good. Then BANG here comes that cyclical vibration, just when I was getting all nice and comfy.

And finally, I need to say this. Tire belts can detach due to poor manufacturing, or external forces. This would be an internal failure, NOT AT ALL visible from the outside. I had one do this on a Ford truck once. Myself and a co-worker were driving to the same place, side by side. At our first rest stop, I told him that I had a bad tire (REALLY bad above 60 mph) and that I'd need to make the whole trip at 50 -55 mph. As the trip went on, things got worse, and I motioned him to get off at the next exit. At this stop I told him to drive beside me when I get to 60 mph, and see if he could SEE which tire was jumping around. It took about 5 miles at 60 mph before he could see all four, and immediately picked out the front left. Next stop was a Ford dealership.....guess what, spin balance was PERFECT! But I refused to accept that and told the tire man to put it on the machine again. Sure enough, the balance was spot on, but when an indicator was brought near the spinning tire, (a pencil) it couldn't touch the visible part of the spinning tire beacause a small section was protruding at least 1/2" out from the rest of the tread! Broken internal belt! 1 new tire, no more problems!

Moral of the story, phase changing vibrations are also speed related. Well that's not the moral, 'cause this story has no moral, but they are anyway, and the story is true.

[Logan]

True. There are paint marks on the tire indicating the high/low spot of the tire. On aluminum wheels this is not a real issue, as you really cannot get a more trued wheel then machined aluminum. This was much more critical in the day of steel rims. The paint mark was to be aligned with the tire valve.

Many tire stores ignore this. Why? The 17 year old mounting your tires has not been correctly trained. He's making $7 an hour..thats more then most pizza drivers these days.

There should also be a #8.

8- Flat spotting. When the tire sits all day. This will create a flat spot on the tire. This does not damage the tire, but may take 10-20 miles to clear up. So if you live 9 miles from work, the problem may always be there, even with the best tires.

Before having RFB done, you need to drive the car about 20 miles for this issue. GM has a bulletin related to that issue.

As for JohnnyG. Your second guess was better.

I drew a very crude cutaway pic. The gray is the rim, black is the tire, red is the tool, blue dots are air.

Red tool is a sealed drum and goes all the way around the tire. Red tool has a gasket to seal itself to the tire. Red tool is pressed on side of tire, inside red tool, air pressure is increased, air can easily flow into tire all the way around the bead, lift red tool in controled fashion, 'pop', tire is seated and inflated.

[Logan]

Ranger- If I had seen any consoles, you would be the first to know. I would try contacting them. I bet he can get you one. They have tons of Cadillac parts. They have 2 locations in Michigan. One in Mason and one in Waterford. Never seen anything like these guys..who has '11 mile' parts available?

I should also add. I do have the GM electronic EVA tool. It's screaming tires are the issue.

If you do NYC city driving, a $67 tire rack tire will work fine. If you do 70 mph open highway driving, your going to have to pony up for the good stuff. You get what you pay for.

This site is also very helpful:

<a href="http://www.vibratesoftware.com/html_help/h...tion_School.htm" target="_blank">http://www.vibratesoftware.com/html_help/h...tion_School.htm</a>

So in my case. My Tire Rack tires are nearing the end. And I have 2 lightly sprung wheels on the rear. My current RFB setup. 9 lbs front. 19 lbs rear. And getting worse...

Tires dont last forever. Wheels can also be damaged over time.

I wish Michelin would bring back the X One in our sizes. Fantastic tire. If you found a good set they could go 60-70K without messing with them.

Cant wait for my '15 mile' factory DTS wheels and factory tires to get here.

[Texas Jim]

If you do NYC city driving, a $67 tire rack tire will work fine. If you do 70 mph open highway driving, your going to have to pony up for the good stuff. You get what you pay for.

I wish Michelin would bring back the X One in our sizes. Fantastic tire. If you found a good set they could go 60-70K without messing with them.

Cant wait for my '15 mile' factory DTS wheels and factory tires to get here.

Darn it... You are costing me money.

I do a lot of highway driving. 70mph +.

I have 41,000 on the current tires.

Between the two 2006 DTS's I have owned... have put over 80,000 on them in 2.5 years and thats not counting about 100,000 on my work vans. BIG OIL loves me. I buy a lot of gasoline.

Will be putting new tires on the DTS pretty soon.

I have ran into a big problem... there are not many choices in my size.

245x50x18

I too wish Michelin still made the "X" tire. I had several sets of them over the years. FANTASTIC tire. Best tires I have ever bought. They still make the "X" for big trucks. My brother drives 18 wheelers. He has Michilen "X" on his 2007 Kenworth. Talking to him yesterday... he has 190,000 on it in just over a year and a half.

Good luck with your new tires and wheels.

REMEMBER.... we need pics when you get them on the car.

[Logan]

Be sure to see:

<a href="http://www.vibratesoftware.com/" target="_blank">http://www.vibratesoftware.com/</a>

Go to downloads. There is a free 30 day trial.

You enter gear ratio, trans ratio, how many cylinders, etc.

It will create a chart of your car where you will see vibrations at what hertz and what engine rpm.

If you look at the EVA picture (post #16) above. At 70 mph. The EVA is seeing 16. Dead on for tire issue according to the chart. Some data does have to be entered in to the EVA. Such as speed of vibration, and tire size. In this case speed is V=70 and tire size is 235-55-17. From there the EVA is even smart enough to classify it as 'TIRE 1' issue. Tire 1 meaning first order issue.

It exactly matches the chart posted below (2001 base Deville). See yellow highlighted area. My vibration is T1 first order tire speed issue. 70mph, 16 hz, 2000 rpm.

Could be the axles or something that turn at the same speed as the tires. But...I think I will suspect the worn tires and China rotors.

Look at the chart, look at the EVA. We all know these cars are at 2000-2100 rpm at 70 mph. The chart nails it dead on as being a first order tire vibration.

[Ranger]

Ranger- If I had seen any consoles, you would be the first to know. I would try contacting them. I bet he can get you one. They have tons of Cadillac parts. They have 2 locations in Michigan. One in Mason and one in Waterford. Never seen anything like these guys..who has '11 mile' parts available?

Thanks Logan. I appreciate you remembering me. I may give them a call in a few days (if I remember). She's got 53K on her now and if I don't stumble across one soon I'm just gonna live with the column shift.

[Logan]

For JohnnyG. These guys do suggest drum / rotor balance as being a possible issue.

<a href="http://www.vibratesoftware.com/html_help/h...tor_Balance.htm" target="_blank">http://www.vibratesoftware.com/html_help/h...tor_Balance.htm</a>

[JohnnyG]

For JohnnyG. These guys do suggest drum / rotor balance as being a possible issue.

I still don't think they can shake the whole car and make the ride uncomfortable. Minor vibration, maybe....just not what you're feeling.

[Logan]

JohnnyG. I still plan on looking into the rotor issue.

It appears in manufacturing that rotor core shift can be a issue. More to come. Pretty easy to find 3/4 oz issue in a 15 lb rotor.

Anyway, the good news today is this post. JohnnyG has seen this:

http://caddyinfo.ipbhost.com/index.php?showtopic=18852

Getting closer.

[JohnnyG]

JohnnyG. I still plan on looking into the rotor issue.

I think that in the end you'll find that this is just another way of redirecting the blame away from poor quality tires, inept workers, and tire salesman that want to sell you substandard quality tires at full retail.