Thrumming Vibration
Thread Starter
2nd Gear
Joined: Aug 2011
Posts: 2
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Thrumming Vibration
I unfortunately/accidently hit a curb while doing a U turn. Rubbed the metal bracket holding the radiator and chipped my aluminum wheel passenger side. Steering was full lock left turn when I hit the curb. Pushed the plastic fender cowling towards the wheel. Dealer fixed the cowling no problem. After scuffing the curb I also noticed a "cycling thrumming" sound similar to going over those speed reduction furrows in pavement. At 40 KM sound barely audible, at 80 and up downright annoying and intolerable. No shake/vibration in the steering wheel. The "thrumming" disappears when a right turn curve on the highway is taken at speed. Dealer thought it was the tires. I requested an alignment and right front tire balance. Problem still there. I agreed to replace both front tires with new Goodyear Supercar rubber but problem still there. Next step is to replace the right passenger side aluminum wheel but parts replacement to sectionalize/find the problem is getting expensive. Any ideas or techiques to find the exact problem before repacing the entire front end?
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,108
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
I unfortunately/accidently hit a curb while doing a U turn. Rubbed the metal bracket holding the radiator and chipped my aluminum wheel passenger side. Steering was full lock left turn when I hit the curb. Pushed the plastic fender cowling towards the wheel. Dealer fixed the cowling no problem. After scuffing the curb I also noticed a "cycling thrumming" sound similar to going over those speed reduction furrows in pavement. At 40 KM sound barely audible, at 80 and up downright annoying and intolerable. No shake/vibration in the steering wheel. The "thrumming" disappears when a right turn curve on the highway is taken at speed. Dealer thought it was the tires. I requested an alignment and right front tire balance. Problem still there. I agreed to replace both front tires with new Goodyear Supercar rubber but problem still there. Next step is to replace the right passenger side aluminum wheel but parts replacement to sectionalize/find the problem is getting expensive. Any ideas or techiques to find the exact problem before repacing the entire front end?
Before you replace the wheel, simply borrow a wheel from a known non-issue car to verify if the vibration is gone. Also, check the wheel with a dial indicator for runout. GM says .030 total is acceptable, but I'd never use one that's more than .010. Even if the wheel is slightly bent, it still may not be the source of the vibration.
Your dealer is supposed to follow the service manual procedures to resolve vibrations. Not just take guesses, especially at your expense.
There is a diagnostic tool to locate the source of vibrations. Tell them to quit replacing stuff until they've determined where the vibration eminates. The tool is a J38792-A Electronic Vibration Analyzer. There is a J38792-VS Vibration Software to be used in conjuction with the tool.
Racer
Joined: Nov 2010
Posts: 287
Likes: 1
From: OK
Possibly a wheel bearing.
Before you replace the wheel, simply borrow a wheel from a known non-issue car to verify if the vibration is gone. Also, check the wheel with a dial indicator for runout. GM says .030 total is acceptable, but I'd never use one that's more than .010. Even if the wheel is slightly bent, it still may not be the source of the vibration.
Your dealer is supposed to follow the service manual procedures to resolve vibrations. Not just take guesses, especially at your expense.
There is a diagnostic tool to locate the source of vibrations. Tell them to quit replacing stuff until they've determined where the vibration eminates. The tool is a J38792-A Electronic Vibration Analyzer. There is a J38792-VS Vibration Software to be used in conjuction with the tool.
Before you replace the wheel, simply borrow a wheel from a known non-issue car to verify if the vibration is gone. Also, check the wheel with a dial indicator for runout. GM says .030 total is acceptable, but I'd never use one that's more than .010. Even if the wheel is slightly bent, it still may not be the source of the vibration.
Your dealer is supposed to follow the service manual procedures to resolve vibrations. Not just take guesses, especially at your expense.
There is a diagnostic tool to locate the source of vibrations. Tell them to quit replacing stuff until they've determined where the vibration eminates. The tool is a J38792-A Electronic Vibration Analyzer. There is a J38792-VS Vibration Software to be used in conjuction with the tool.
Team Owner
Joined: Sep 2000
Posts: 25,029
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From: Far NW 'burbs of Chicago
St. Jude Donor '13
You could even flip your front wheels, left to right, for a quick test. Running the tread "backwards" for a few miles won't hurt anything. But sometimes it's difficult to tell whcih side the noise is coming from. Good wheels from another car are better.
If you can get a Hunter Road Force balance in your area, that will tell if any wheel/tire is out of round or out of true.
But I'm with HOXXOH, wheel bearing is quite possible.
If you can get a Hunter Road Force balance in your area, that will tell if any wheel/tire is out of round or out of true.
But I'm with HOXXOH, wheel bearing is quite possible.
Thread Starter
2nd Gear
Joined: Aug 2011
Posts: 2
Likes: 0
Cycling Thrumming Noise
Thank you for the advice you provided particularly the suggestions that it was a bearing/hub issue. Indeed the dealership replaced the passenger side front bearings and the problem is resolved. My only regret is that I didn't put this thread on the Corvette Forum when I initially had the problem and prior to them replacing the front tires. Although worn they could have lasted me through this summer. Oh the other regret is hitting that curb to begin with. Anyways the love affair with my Magnetic Red 2005 C6 Corvette is back in full bloom. Thanks to everyone for their input.
