Heavy spot in wheel

I have a set of American Racing Vectors on my 'Vette. I had them spun before mounting the new tires to be sure that they were not bent or distorted - they checked out OK. My problem is that one of the wheels has an extremely heavy spot in it. The tire was removed and the wheel put on a balancer without the tire, this was how the heavy spot was located.
The wheel/tire combo have been rebalanced several times but an excessive amount of weights are needed on this one wheel. I am still getting vibration at highway speeds.
How do I remove some material from the wheel to minimize the heavy spot. Can I use a random orbit sander to clean up the back/inside of the wheel or do I have to send it out to a specialty shop?

Long as the thing runs CONCENTRIC, i'ts fine....if it's out of balance, you maybe try sticking some weights on it with no tire,....

then balance the tire on there, and see what happens.....quite often a tire wheel takes too much weight....anyting over 2" long in one spot is too much IMO.....so I make them spin the tire on the wheel about 180* and then do the balance again....most often it's fine then....

any GOOD tire shop does that automatically without asking, Up in the Wash DC area the only good tire shop is Radial Tire Co.....in Silver spring Md...

they have the same crew working for some 25+ years now....

turning some 8 MILLION BUX in sales/year......

that's a lot of rubber on the road....

:bump:

Hi Gene, Yes, we did that twice now. The rim is just way heavy in one spot and needs excessive weights to set it right. The tire has been rotated 180*, as you suggested, still the problem persists.
I have located a wheel specialty shop here in NJ called WheelWorks, they specialize in customizing wheels for rodders, they come highly recommended.

DeeVeeEight said:

Hi Gene, Yes, we did that twice now. The rim is just way heavy in one spot and needs excessive weights to set it right. The tire has been rotated 180*, as you suggested, still the problem persists.
I have located a wheel specialty shop here in NJ called WheelWorks, they specialize in customizing wheels for rodders, they come highly recommended.

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OUCH....hope it don't cost you another mortgage.....

Me too. When I described the issue to the owner he was able to quote me a price range of $100 to $150, it's cheaper than buying a new wheel.

DeeVeeEight said:

Me too. When I described the issue to the owner he was able to quote me a price range of $100 to $150, it's cheaper than buying a new wheel.

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Yeh, they want good bus these daze for doing jack diddly on a wheel....even here in cheeep old Jax Florida.....

:crutches::flash:

Update

I ended up putting the wheel on a wheel balancer with no tire on the wheel. The wheel was heavy by 3.75 oz. on the front and by 2.75 oz. on the back, both measurements within about 3" of each other.
I wound up taking a 4" grinder to the inside of the wheel and removing material (in a wide area) until I was at 2 oz. at both heavy spots. The tire was mounted and balanced again. This time the results were favorable and the tooth rattling vibrations at highway speeds are gone.

That's good news :thumbs:

Any idea why there's a difference between removing mass vs. adding mass ??

MYBAD79 said:

Any idea why there's a difference between removing mass vs. adding mass ??

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Picture a lightweight spinning assembly like a bicycle wheel spinning at a thousand RPM---A 1 oz static imbalance would tear it apart due to the centripital force (or at least throw it across the room!). If you add 1 oz on the opposite side, the assembly will be statically 'balanced', but the forces will still be there in opposition, trying to tear it apart but relying on the strength of the assembly to hold it together (but creating a vibration).
By removing the heavy spot you reduce the centripital stresses, even though in real life you will still have to compromise by having to add some weight in places to balance the assembly.

DeeVeeEight said:

......problem is that one of the wheels has an extremely heavy spot in it.

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DV, I hate to bring this up, but that's kind of scary to me--I can only think of 3 reasons for that:

-The rim was cast off-center & but machined to spin true irreguardless of balance
-There is an impurity cast into it which is heavier than the material of the wheel
-There are air pockets in the casting which only show up as a heavy spot opposite them

The last two especially make me envision catastrophic failure of the wheel at high speed.
Sorry....

.......maybe this will help put it into perspective: 3.75 ounces is damn near a quarter pound! --that's a lot, that's heft in your hand. A 1/4 pound in only 15" diameter of an (I assume) aluminum alloy casting is way way WAY too much to be any kind of "innocent" problem.

John

I wish I had taken pictures of it while I was doing the work. I do not disagree with your concerns. I went through a lot of agonizing before picking up the grinding wheel. I did not remove a lot of material in one concentrated area but spread the area a good 12 or more inches to either side of the heavy spot.
I had the wheel checked by the respected wheel specialist and while he did shave the back of the hub ever so slightly he assured me that there was nothing significant that he could find wrong with the wheel. The wheel is not bent or out of round.

I had the car out again today at various highway speeds and for a 30 year old car with 30 year old technology it rides smooth enough.

I don't know how you might test a wheel for impurities.... Take it to a titty bar, or sprinkle it with Holy water, maybe get it an exorcism or something???

I can only think of magnetic or sonic testing, but the wheel ain't worth that much effort. It's on the car and the results are pretty good, plus I had a chance to play with the grinder :smash: and actually do some of my own work on the car instead of paying someone else to do it. I have the satisfaction of having done it myself.

DeeVeeEight said:

I had the wheel checked by the respected wheel specialist.....

I don't know how you might test a wheel for impurities.... Take it to a titty bar, or sprinkle it with Holy water, maybe get it an exorcism or something???

I can only think of magnetic or sonic testing,

.... I have the satisfaction of having done it myself.

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:devil: the car is your dependant.... Your 'health insurance' should cover an MRI, or at least X-rays. But a titty bar exorcism with some 86 proof holy water couldn't hurt......

You are not stupid, DV. I know that. If you feel confident you have solved the problem & are not worried, cool. I'm sure I'd do the same. :thumbs: