Wheel vibration, not un-balanced tires...

[rothsean]

My car has always had a slight vibration starting aroung 50mph thru 70mph. It is not too bad, but the wheel will bounce back and forth 1/8" during these speeds.

I put new tires on and they are balanced, checked twice, and it still happens. The tires were old before anyways so I wanted a new set regardless.

Any ideas of what else to check if tires are balance?

[Jonathan]

Sounds like you need an alignment. The tires can be perfectly balanced independantly, but if all four wheels are not pointing in the right direction as a whole, you will feel these sorts of bumps and vibrations.

[rothsean]

Sounds like you need an alignment. The tires can be perfectly balanced independantly, but if all four wheels are not pointing in the right direction as a whole, you will feel these sorts of bumps and vibrations.



I just had it aligned too when I got the tires at Firestone. I even gave them the specs.

[David T]

An alignment would have NOTHING to do with vibrations. If the wheels were dynamically balanced and you still have vibrations it could be a bad tire or a bent rim. Check the lateral run-out of each rim. Run you hands over the tread and the sidewalls and feel for lumps, bumps, bubbles, separations, anything that does not feel smooth. If you feel something then that tire is probably bad. If the date code is over 7 years old just replace them. Make sure you are keeping the correct pressures in the tires. Make sure the lug nuts were torqued to the proper spec in sequence. Make sure the rim is properly seated on the spindle or the axle, ie, there is no dirt or rust preventing it from seating all the way on. If the steering wheel is shaking it is probably a front tire, if you feel your belly shaking it is probably a rear tire.
David Teitelbaum

[DMCMW Dave]

Bent wheels, or a bent hub (yes - I've seen this one).

Lift the car off the ground and spin the wheels. This will show you out-of round tires and bent wheels.

[Jonathan]

An alignment would have NOTHING to do with vibrations.

Oh, sorry. My mistake. I didn't realize the self appointed guru was going to chime in with another "perfect diagnosis" and set this fellow straight. Heck, we all know as soon as the know-it-all guru pipes up the rest of us are wasting our time offering up other ideas or suggestions. Cause really, there is just such a long list of threads where one of your obnoxious NO THAT'S NOT IT, IT IS THIS, actually helped the guy and he chimed in soon after to say, 'wow, thanks for pinpointing my problem so quickly and easily.' Knock yourself out Teitelbaum, the floor is all yours.

[David T]

Everyone's advice is always welcome, where did you get the idea that when any particular poster offers advice no one else can comment? I did want to correct you though, an alignment has nothing to do with vibrations. Vibrations are caused by something that rotates and is not balanced or running true. Alignment affects ride height, handling, steering and tire wear. They are commonly confused and shops seem to also perpetuate that, that way they can do more work and charge for it. In many shops they seem to automatically do the two together. Especially if they are selling a set of new tires. The tires MUST be balanced but if the old tires wore evenly there is no need for an alignment. Signs of needing an alignment include:
Not wanting to go straight, leading to one side or the other or pulling to one side and NOT during braking
Tires not wearing evenly across the tread
Going straight down the road and the steering wheel not pointed straight ahead
The rear wheels not following the front wheels
After replacing any part in the front end that can affect alignment
All too often people think they need an alignment when what they really need is to replace worn parts. The big sign of that is lost motion (play, looseness) in the steering wheel. To avoid that, regular lubrication and inspection is very important. Replace and damaged, torn, missing seals and boots quickly.
David Teitelbaum

[LEVY]

Everyone's advice is always welcome, where did you get the idea that when any particular poster offers advice no one else can comment? I did want to correct you though, an alignment has nothing to do with vibrations. Vibrations are caused by something that rotates and is not balanced or running true. Alignment affects ride height, handling, steering and tire wear. They are commonly confused and shops seem to also perpetuate that, that way they can do more work and charge for it. In many shops they seem to automatically do the two together. Especially if they are selling a set of new tires. The tires MUST be balanced but if the old tires wore evenly there is no need for an alignment. Signs of needing an alignment include:
Not wanting to go straight, leading to one side or the other or pulling to one side and NOT during braking
Tires not wearing evenly across the tread
Going straight down the road and the steering wheel not pointed straight ahead
The rear wheels not following the front wheels
After replacing any part in the front end that can affect alignment
All too often people think they need an alignment when what they really need is to replace worn parts. The big sign of that is lost motion (play, looseness) in the steering wheel. To avoid that, regular lubrication and inspection is very important. Replace and damaged, torn, missing seals and boots quickly.
David Teitelbaum

Yes sir, out of alignment can eventually cause vibration!

No need for a 1000 word essay to explain but if you need an explanation, let me know.


LEVY

[Dangermouse]

Bent wheels, or a bent hub (yes - I've seen this one).

Lift the car off the ground and spin the wheels. This will show you out-of round tires and bent wheels.

As my DD has just been diagnosed with a bent wheel, this was my first thought too. The shop discovered it while balancing the wheel (or trying too).

If it is a new tire that has been professionally balanced (twice), I would have assumed that the balancer would notice at least once.

So that leaves bent hub or rotor issue.



Actually re-reading the OP, would a failed steering rack firewall bushing have the same symptoms?

[Elvis]

Had a bad ball in one of the bearings.
There must be a picture somewehere here.

It drove me nuts for several years...

Might be worth to take a look.

[Rich]

Any ideas of what else to check if tires are balance?

Yes, and the answer is the same for any car. Be sure that your shop uses a machine that dynamically reads the road force. A tire and wheel can be balanced yet still cause a vibration at driving speeds - just as you report.

Had a similar problem on one of my other cars. The local shop's balance job was "perfect" according to them but the vibration persisted. Went to a suspension shop that had the right machine and the problem was solved. Yes, it cost extra. But less than more useless "balance" jobs would have cost.

This machine can uncover the lateral runout problem David T mentions, as well as other potential sources of road force variation. See this linked technical piece:

LINK: http://www.tirerack.com/wheels/tech/techpage.jsp?techid=109& (http://www.tirerack.com/wheels/tech/techpage.jsp?techid=109&)


"The GSP9700 Vibration Control System includes Hunter's exclusive Road Force Measurement System to help detect potential tire uniformity causes of vibration that are not balance-related."

[LEVY]

And to add something to Rich's post:

Some times your tire/wheel is so bady out of balance, that some shops are only allowed to add so many weights, if your wheel still out of balance, the technician will just leave it like that. I know first hand Wal Mart is one of those, if you notice and ask, they will blame your wheel and not the new tire.

LEVY

[Ron]

... if you notice and ask, they will blame your wheel and not the new tire.

LEVY
lol
I wonder what they say if you ask them why it wasn't a problem for the last 30 years...

[Michael]

Just so you know, you can balance a brick...but it still will not be round. Tires CAN be bad, even if they balance perfectly.

Yes I personally saw a brick with the proper weight balance perfectly on a tire balancer as a demonstration.

[David T]

I have seen kids try to balance obviously bent rims too. You can get them dynamically balanced (yes, even a brick) but just because you can balance it doesn't mean it will work on a car without severe vibration. I have also seen what looks like perfectly smooth running and balanced tires feel horrible when driving. The ultimate is a force balancing machine but not a lot of shops have them. A tire can have hidden defects or damage, look fine visually, but vibrate badly at certain speeds. Usually the best way is to just substitute a known good tire and see if the problem goes away if you don't have a force balancer.
David Teitelbaum

[LEVY]

Just so you know, you can balance a brick...but it still will not be round. Tires CAN be bad, even if they balance perfectly.

Yes I personally saw a brick with the proper weight balance perfectly on a tire balancer as a demonstration.

Yes, you can balance out of round objects, that is the reason some shops only allow so many weights on a wheel. If your wheel needs more than two or three weights to balance (or very big weights), then something is wrong.

If you are buying new tires and your old tire had only an small weight and it was fine, then your new tire should not need many weights, if it does, then your new tire is defective.

LEVY

[Ron]

If you are buying new tires and your old tire had only an small weight and it was fine, then your new tire should not need many weights, if it does, then your new tire is defective.
Unless the last guy static balanced it with the tire (the way they used to do to save weights) before putting it on the machine...

[DMC5180]

Make sure tire pressures are equal from side to side.

[Jonathan]

Brainstorming ideas... just thinking out loud in case it triggers something the OP might realize is going on with his car.

If the vibrations get worse the faster you go... what parts of the car are affected by higher speeds?

Wheels rotating of course

Perhaps the brakes on those wheels, like if a caliper was sticking, would this be noticed at higher speeds? Parking brake calipers on rear wheels?

Front left wheel angle drive and speedo components spin faster as you drive faster

Wind related vibrations? Louvres can rattle or vibrate, so could the lower engine cover. Perhaps some of the skirting under the car might vibrate at higher speeds if it wasn't clipped in properly? A loose side mirror might vibrate in the wind? Windows? Air inlet vents at the rear (passenger side that sucks in air to the engine; drivers side that sucks in pretend air to your antenna)? Heatshield not connected correctly dangling down? Air deflectors covering TABs still attached as they should be?

Engine likely spinning at higher RPMs as you drive faster... not sure something here would be only noticed at higher speeds... like a misaligned pulley or loose belt.

Visual inspection of your rear drive axles to see that nothing is caught or hanging on them? Boots ok?

......

I drove a SmartCar years ago as a rental while working in Sicily. It used to "speed wobble" at about 105 km. Not sure what it was, but I kept it under that speed because of it. There are plenty of other Ds that don't speed wobble though, so we should be able to figure it out.

[Dangermouse]

I'm assume from you post that the vibration is felt through the steering wheel while driving and not braking?

I would take Daves advice in post 3 first - cheap and easy.

If you are in an owners club, perhaps swap front wheels for a pair of known good ones. That would eliminate both wheels and tires.

[David T]

The amount of vibration increases as the amount of mass out of balance increases and/or the distance it is from the axis of rotation and the speed of rotation about the axis. Because the rotors are very symmetrical and close to the axis of rotation it is not likely the rotors are the cause. A sticking piston in a caliper won't affect balance but it would cause a lot of heat and drag. There is always *some* vibration but it is not usually noticeable because it gets damped out. There are frequencies where the vibration can resonate and become powerful enough that it isn't damped out. That equates to a particular speed where the vibration is most noticeable. There is not enough mass in the speedometer system and it is on the axis of rotation so any contribution from that is negligible. In just about all cases the vibration will turn out to be something bad or bent with a tire, rim, or hub (or bearing for the hub or spindle). Modern tires have a dot or other indicator where the tire is supposed to be installed in relation to the tire valve. If that is not done it can cause vibration and the need to add excess balance weight. Some shops will sell what is called "Blems" in the industry. They are less expensive than first rate tires. In many cases it is only cosmetic but sometimes the defects are more serious that that. The big problem is most people do not know that and pay full price for what the shop got a deal on. Then when there is a defect the shop won't admit they are using inferior tires. They may try to tell the customer it will "work itself out in time". Good luck with THAT! If all of a sudden you notice a vibration on older tires it could be the belts inside the tire have shifted or maybe you damaged them hitting a curb or a pothole. Or bent a rim or a hub. The very first thing you should do is CHECK THE TIRE PRESSURE. A tire that is low will cause all kinds of warnings. Often when a customer comes in to get tires balanced all they really needed was air or to fix a slow leak. They get that AND balance all of the tires and if it's a slow day they will also get an alignment!
David Teitelbaum