Vibration

[Dcalebaugh]

Here is one you guys and gals may have experienced before. I had a substantial vibration in the steering wheel at speeds above 50. I brought it in to the tire shop and had all the wheels balanced. The tire mech said that three of the four wheels had run out. So I purchased four wheels on Ebay from Toms Wheels, stock 86 wheels that had been chromed. Look good on the car but you guessed it, it still vibrates. The mech said that one of the new wheels had some run out, not bad but some so I put it on the back. I can feel the vibration in the wheel as a left to right shake. I will try new tires, but I am curious, is there something I am not checking?

Thanks
Dave

 

[rrubel]

Bad wheel bearings and ball joints can cause wheel shake at speed...

[RICHR]

 

[LarryBible]

The most common source of vibration on alloy wheels is the tire store doing a STATIC balance. This is where they set their balancer on the static setting and add balance weights ONLY to the inboard wheel lip. This keeps the wheel from hopping up and down but allows it to "wobble."

This is commonly done by the tire stores because they have had complaints about the look of weights on the outboard lip, or about scratching the wheels when putting the weights on the outboard lip.

Go out and look at your wheels. Are there any weights on the outside? If not are there any tape on weights just behind the spokes? If there are no weights in either location, they did not DYNAMICALLY balance the wheels.

Corvette wheels are BIG and they are WIDE, which makes it even worse when they are static balanced.

I got so frustrated with the tire stores not balancing my wheels correctly that I shopped around and found a good, used Coats 1001 wheel balancer. I balance them myself now, ALWAYS using weights inboard AND outboard. Any car on my place now can run as fast as it will go with NO vibration.

My Vette wheels have considerable runout, but if properly balanced I can run it way over 100MPH with no vibration.

Find a shop that will balance them properly and I give you a 95% chance that the vibration will disappear. If it doesn't, go to: www.gsp9700.com On that site you will be able to find where there is a shop near you that has a Hunter GSP9700 wheel balancer. This machine not only balances, but uses a pressure wheel and other measurement instrumentation to diagnose the wheel and tire. If you have a tire with excessive road force vibration (stiff spots) this machine will tell you that.

Again, DYNAMICALLY balancing will most likely cure your problem. If the shop did indeed not use weights on the outboard lip and even did so after you described your vibration, you MUST find a different shop.

Good luck,

 

[Dcalebaugh]

The store put tape on wieghts on the inside. The guy said that the front right tire was out of round and he couldnt guarantee the balancing, although I have not noticed any abnormal wear on that tire. I will need to replace the tires at some point due to normal wear, but if I can get them balanced for now I will wait tll next year. I do have a Ford dealer in town that has the Hunter balancer so maybee thats the best route to go. What would be an easy check for wheel bearings or ball joints? It tracks nice and true and I do not hear any noise from the front as I have heard with other vehicles Ive owned with bad bearings. Any suggestions for tires?

Thanks
Dave

 

[Vrotate]

vibration

My old 85 had the same problem above 50. I tried everything. It was a combination of a lot of things. The biggest vibration was an axle out of balance. I bought a new one in a salvage warehouse in bowling green. It helped terrmendously.

Check all the alluminum axles!

Everyday Vetter

Vrotate

 

[LarryBible]

1. You say they used tape weights on the inside. Do you mean just behind the spokes in addition to weights on the inboard lip? If they used tape on weights ONLY on the inboard edge of the wheel ONLY, this is a static balance. There need to be weights on the inboard edge AND outboard edge. Using tape weights just behind the spokes in addition to inboard weights, either tape or clip gives them two planes to balance from to accomplish a dynamic balance. Weights, either tape or clip on the inboard ONLY will not get a dyanamic balance and you will have vibration.

2. Hunter makes many very good wheel balancers, but most of them will do no more than any other computer balancer. See that the one the Ford dealer uses is the GSP 9700. If it is not that model, it will not accomplish what you are looking for.

3. There are indeed other rotating assemblies that cause vibration, but this is not a common problem. Do not give up on your wheels and tires being the source of the vibration until they have been analyzed on a Hunter GSP9700. I know it sounds like I'm a salesman for Hunter, but I'm not, I just know the prowess of this machine.

Best of luck

 

[Dcalebaugh]

I used the link you provided and then did a search on their site to find a local rep. I will call them Tuesday. I checked the rims again and the only weights I see are stick ons mounted behind the spokes and almost to the back edge of the rim. Hopefully the ford dealer can give me some insight. I will let you know.

Dave

 

[LarryBible]

This weight placement indicates that they did indeed do a correct dynamic balance.

It is definitely time for the 9700, it should tell all.

Good luck,

 

[rrubel]

I happened to be in my local NTW last night, getting my new tires mounted and balanced on their rims so I asked about their balancing equipment. They've got a Hunter, but it's a 1050. I also asked about static and dynamic balancing and got blank stares - the one person who recognised the term tried to tell me that dynamic is basic simple balancing. No, right? I did notice that the weights are on the inside edge and also taped near the spokes on one set and on the inside and outside edge on the other set.
[RICHR]

 

[LarryBible]

rrubel,

You experienced the exact situation that led me to buying my own balancer. Except I experienced that situation multiple times that led me to that extreme.

The terms "Dynamic" and "Static" are very basic terms. A person who claims to be a tire balancer has obviously not even so much as perused the manual that came with their balancer.

The Hunter 1050 is a very good balancer as are many that are in the stores and will do a great job if weights are used on two planes as you describe, and if just a little care and concern is exercised by the operator. I believe that I could teach anyone with an IQ above 70 how to properly balance tires in less than a half hour.

The difference between the Hunter GSP9700 and any other balancer including all other Hunters is that it has a pressure roller wheel that applies 700 pounds of force to the tire and measure the road force variation around the entire tire. It also measures tire and wheel runout. It is not just a wheel balancer, it is a tire and wheel analyzer.

Dynamic balancing is not basic, simple balancing in the sense that it is something less than static. Static balancing requires weights ONLY on one plane, Dynamic requires weights on both planes and will prevent the wheel from "wobbling."

You can learn much more at www.gsp9700.com Poke around and look at technical information.

Have a great day,

 

[Vettelt193]

Tire shops always amaze me... Not only are they too stupid to know how to balance a tire, but they don't even know anything about tires... My last experience with a tire shop was putting new tires on my old '93 vette. I was replacing with a set of GSC's, which were tires that chevrolet and goodyear developed for the Corvette, and were factory equipment on my '93. The tire guy inflated the tires to the max tire pressure written on the tire, and i told him I wanted them to the factory specs (32 psi i think, he had them to well over 40 psi) He then explained to me how the tire manufacturer knows more about the tire than the car manufacturer blah blah blah... after i explained to him about max tire pressure, the goodyear/corvette relationship etc. he still didn't believe me... I just told the guy to pick up a book on tires so he can stop giving out mis-information to people who think he is an expert.

 

[LarryBible]

Vettelt193,

Yes, it takes five minutes to read their brochure and know more than most tire stores do.

Have a great day,

 

[c4ever]

Dave,
I recently had the same annoying vibration at 65-70. Had two balances done ,no change. Had them balanced on the Hunter9700, vibration gone. I don't know whether it's a "I don't care" attitude or just plain stupidity but I have to agree with the others. Most tire shops need to read the "Book Of Instructions"
Good luck with it.

Carlo

 

[compyelc4]

Funny! I just got back from BG and Nashville. My '95 was just terrible at about 73 mph and above. I went out this afternoon and had Pep Boys spin balance the things. I asked if they could place the weights on the inside and still get a decent balance. They said they would try, but if I was not satisfied to bring it back to add weights to inside and outside.

What a nice surprise. Not only did the old weights not leave marks on the outside where they were originally located, but the weights on the inside work just fine. I ran her up to 90 or so a couple of times. Smooth as silk. Also, I was scared that some wrench-head would:
1. scar up my pristine rims
2. torque the bolts to 500 ft. lbs!

I experience neither! I'm going to write them a nice letter. They did nice work.

I am not real knowledgeable about balance lingo, however, I always thought static balance was "place the rim on the bubble and add weights til the bubble is balanced." Dynamic is "spin" the wheel and let the machine figure out how much weight to place where." I have not been able to find a shop in our local area that actually spins the wheel right on the car any more. I always found that to work the best because it compensates for imbalance in the rotors as well.

 

[LarryBible]

compyelc4,

You are very lucky, you should go out and buy a lottery ticket.

You are correct in your assessment of static balance. Static balance can be accomplished on a bubble balancer. It will keep the wheel from jumping up and down. The computer balancers have a static mode that accomplishes the same balance, except by spinning the wheel. If you watch most balancers in static mode, you will see only one part of the panel giving information. This is because it only needs weight in one plane, but it is the same effect as a bubble balancer.

When the machine is used for dynamic mode, both displays will offer weight size and location data. Most machines, even my 12 year old Coats 1001 has a mode that resolves weight data for the use of tape weights behind the spokes as well as on the inboard lip, to accomplish a two plane, dynamic balance using these tape weights to prevent scratching the outboard wheel lip.

I can assure you that there is some vibration in your wheels due to the static balance method used. In fact putting weights inboard only actually aggrevates the dynamic imbalance. In your case it's just not bad enough to feel a vibration, or you are used to this and don't sense one. I fully expect that I could balance the wheels on your car with tape behind the spokes and you would be able to tell the difference at 90 MPH easily.

Best of luck,

 

[Dcalebaugh]

Well I ordered new tires(Dunlop Sport 8000)and will make an appointment to have them balanced on the Hunter. I jacked up the front end and checked for free play from the ball joints and wheel bearings. It felt tight to me and the ball joint wear indicators look ok. While I had it up I verified that the only weights on those wheels are stick ons on the outboard side only, no other place, and the tires have a distinc hump in them. I will post the results of my new tires and balance. Thanks for everyones input.

Dave

 

[compyelc4]

LarryBible-

I'm on the next plane to Texas. Tires/wheels are in the cargo hold! Thanks for the offer.

 

[Dcalebaugh]

Well the new tires arrived and had them installed and pro balanced, inboard and outboard weights. Two rims did have some run out and were placed on the back, the other two rims were straight and true and went on the front and like magic no more vibration. Thanks to all for the help. It's great to cruise at 80 with no shake.

Dave

 

[CorvetteArchives]

Glad to see u solved the problem. I was going to suggest the tires as the culprit. A friend of mine couldnt figure out why she was getting a shimmy this spring.......turns out she didnt drive or store the car properly over the winter and a slight flat spot was driving her nuts!