Question about tire vibration

[Baldie88]

When I bought my 88 it already had fairly new Dunlop SP5000 tires on it. I think there may be only about 6-8000 miles on them now. I've always had a vibration problem and recently took it to a shop recommended by the local Vette shop to have it aligned and balance the tires. Still wasn't happy with the balance and took it back again last week.

First time I did any long distance driving was yesterday and I've still got a vibration problem. Starts about 55-60 and gets progressively worse. At about 80 the mirror vibrates so much I can't see out of it.

I'd sure hate to get new tires since there is still a lot of tread left but I can't stand to drive it this way. ad Is there a way to determine if maybe I've got bent wheels before I go buy new tires? Since I don't drive it much do tires still get flat spotted? I figured that after a 200 mile trip if they were flat spotted it would go away. Is there anything on the suspension I need to check? As far as I know the shocks and everything else are still original. Have 39K miles on the car.

Appreciate any help.

Baldie88

 

[tnovot]

Is there a way to determine if maybe I've got bent wheels before I go buy new tires?
Baldie88

I see you belong to a Corvette club. Do you know anybody well enough to switch wheels/tires for a short time? If the vibration goes away, you have eliminated the suspension, shocks, etc as a cause. If you then switch back only in pairs, you can narrow it down to front/back, left side/right side/ etc.
A good tire shop should be able to check for a bent wheel and/or broken belt in a tire.
Terry

 

[c4cruiser]

Check out this link http://128.242.141.111/pub/technical/4127T/4127t.cfm This machine is great for finding vibration issues. The site has a locator feature that will help you find one in your area.

I have my race tires balanced on this equipment at the local Discount Tire store. Costs a bit more but it really does the job.

 

[MyOtherCar]

Hey There Ron, I see your question got an immediate (and excellent) response right off the bat. When we talked about this I was more focused on figuring where your vibration was coming from, and if not a tire(s), then driveline or suspension item???? As the vibration is always there, and you refuse to keep it under 90, I was wondering if you checked w/Zeke for possible solutions?

If all else comes up deadend, you can use my tires/wheels as TNOVOT suggested. Mine is in storage but I'm sure we could work something out if push comes to shove. Let me know...
Bill

 

[wx briefer]

Ron, if I were to look at your tires for a problem, I would first look at the amount of weight on each side of the wheel (more than a couple of ounces is not good). I would then look at the location (opposing weights 'on the order of 130 to 180 degrees from each other' on opposing sides of wheel is not good either).

If the above looks OK then you need to go find a dealer that has a hunter 9700 balancer. It is capable of putting a 500 pound force against the face of the tread with a roller which allows flexing of the plies as the tire rotates to make sure there is nothing wrong on the inside of the tire layup.

I have had 2 michelin pilot sports swapped out just a couple of years ago because of too much lateral runout detected by the above machine. I was having a very annoying high speed vibration because of internal problems with the tires.

Of course, check the wheels for trueness while on the balancer.

Believe me, every manufacturer lets bad tires get on the market from time to time. It is up to you to complain and refuse to bounce down the road until the tire wears out (or shakes your car apart).

 

[JEFNLSA]

Hunter 9700

Had the vibration problem...The Hunter 9700 solved it. $80 and well worth it.

 

[Gman]

I had a vibration between 60 and 75 that I chased and gave up on. The vibration wasn't as bad as yours, Baldie. I recently put new Brembo slotted rotors on and the vibration disappeared. Nothing else was changed.

 

[Baldie88]

Thanks for all the replies. Bill, I'll call Zeke and see if he has a set of tires/wheels around the shop that I can try. I'll also check out some of the shops that have the Hunter balancer. When I lived in St. Louis the Hunter training facility was about a mile from where I worked. They use to always want cars for the students to work on so I always had my tires balanced by them. I was always assured they were perfect because the instructors wouldn't let anything get past them.


Thanks all.

Ron
Baldie88

 

[slapshot]

I have the same tires on my 91, they have about 5k miles on them. I don't have any probs with vibrations. I will get a slight virbration after the car has sat in the garage alot, but it goes away quickly once the tires heat up.

I'd try a different shop to balance them, that is about the cheapest thing to check. Have them check the wheels too and make sure they are true round. How are the tires wearing, are they wearing evenly, or are there low spots??

 

[Baldie88]

I took Bill's (My Other Car) advice and I'm going to the local Vette shop and try a set of tires/wheels he has off of a 90 model. If it doesn't vibrate then I know the problem is with the tires. I found a local shop (Dunlop store of all places) that has a Hunter balancer and will see what they can do with them if the 90's tires don't vibrate. I did finally look at the receipts and there is about 11,000 miles on mine. I also just looked and there are 2 fairly large weights on the right front which makes me suspect about the tires. I guess I'll know more after tomorrow.

What I'd really like to do is buy a set of chrome wheels and new tires but having just retired I need to watch my pennies.


Thanks for all the help.

Ron
Baldie88

 

[96corvetteLT4]

I have the same tires only on the front of my car. It has always had a vibration problem (small) above 50. Sometimes it is worse than others. The tires seem to flat spot easily. One way I found to lessen the vibration was to raise the air pressure from 32 psi to 35 psi. This did not eliminate it, but it did make it better. I am hoping the front tires wear out around the same time as the rear ones so I can replace them as a set.

 

[Baldie88]

Update

Thanks for the tip to Bill (My Other Car) I took it to the local Vette shop and we put a set of 90 wheels/tires he had on it. This is after the shop owner drove it and said there was definitely a vibration problem. Put the back ones on first and could definitely tell an improvement and then with the fronts on there was no vibration.

Took one of the fronts up to a local tire shop to check the wheels and tires. Before doing so we noted a lot of grease and brake dust on the inside. Thinking this may be part of the problem we went to work with a stiff brush and Simple Green. After we got it all clean we took the tire to the tire shop. The wheel had just a slight runout problem and balance was a little off. Rebalanced it and then took the other front and this one was perfect. So I cleaned all the rest of the insides up and took the two back one up. One was perfect and the other was just a little off like the front one. Funny thing is, both the right sides were the ones with the slight wheel runout and out of balance so I couldn't just put any "bad" ones on the back.

Drove it again and while there is still a slight vibration at about 80, it is definitely about a 95% improvement over what it was.

While the tires were off we noticed the brakes were starting to wear pretty good so I'm going to take it back next week for brakes and while it's there he's going to check the bearings and u-joints but he doesn't think that's the problem.

So there might be a tip here that if you have a tire vibration problem you might want to check the insides of your wheels and clean off any crud before you spend big bucks on new tires.

Thanks Bill.

Ron
Baldie88

 

[Chetzki]

I just went through all this...

I'm putting this here for the benefit of others reading this thread. I had the same symptoms and using sticky weights on the inside of the wheel well solved it.

http://corvetteactioncenter.com/forums/showthread.php?t=55615

Chetzki

 

[gmhowe]

Had the same problem even after having all 4 balanced, took it back and the did something ( I can't remember the name ) but actually had a machine that showed them where to move the tire on the rim then they rebalanced and all better

 

[JEFNLSA]

Had the same problem even after having all 4 balanced, took it back and the did something ( I can't remember the name ) but actually had a machine that showed them where to move the tire on the rim then they rebalanced and all better

That's the Hunter 9700.

 

[wishuwerehere82]

I have been having a vibration problem on my "87 Lesabre with brand new tires. I pulled them off to put snow tires on this fall and sure enough there was a big blob of grease on the inside of the wheel. That was enough to put the whole wheel out by about 1/2 Oz.