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I have a 2021 C8 Corvette, the last 4 times on start up and only while in Reverse in backing out of the garage one of rear tires feels like its completely out of round. It sounds like I am backing out over some rocks. However the driveway and the street are smooth. When I put it into drive there seems to be no drive ability issue. The tires look great and all 4 are at exactly 30PSI. The first time it happened the temperature was 39 degrees and I have a Z51 with summer tires. But the car was in the insulated garage which is much warmer than 39 degrees.
I looked at the Vins recall for the missing ball bearing Recall in the 21 and 22 Corvette and my vin was not listed. The Car has just under 6000 miles. The transmission seems to be fine.
Anybody have any clues ? As soon as it stops raining I will drive it and take it in to the dealer.
That’s completely normal. You are most likely feeling the sway bar binding up a bit because it’s cold. That happens not only on my C8, but also my M3, 911s , GTI, and 944. It does feel like something is wrong (or that you backed up over something), but again, it’s totally normal.
Were you turning while you were backing out? There is a known condition where the tires will "hop" when cold while turning.
Wow now that you say that, It occurred while I was backing out and then turning to go on to the street. My wife described it as jumping and you called it hopping. Is there anything to worry about ?
Wow now that you say that, It occurred while I was backing out and then turning to go on to the street. My wife described it as jumping and you called it hopping. Is there anything to worry about ?
No, the C7 Z51s were a lot worse. It is because of the partial Akerman geometry for steering response.
Wow now that you say that, It occurred while I was backing out and then turning to go on to the street. My wife described it as jumping and you called it hopping. Is there anything to worry about ?
Wow now that you say that, It occurred while I was backing out and then turning to go on to the street. My wife described it as jumping and you called it hopping. Is there anything to worry about ?
So when I first researched this I thought I had hit on it with the half shaft ball bearing replacement and GM just had missed me as one of the 22 or so Vins.
However if this was a problem, I never read how it would have been diagnosed or if it would cause the characteristics I was experiencing.
From the comments on the board what I experienced seems to be normal. But it does not seem normal to me. I know the first time it happened I got out of the car and inspected the rear.
Thanks for all the wisdom that was shared. It makes me somewhat relieved.
Last edited by Zymurgy; 12-29-2022 at 04:56 PM.
Reason: Links to other Corvette Forums is not allowed
It could be a result of a lot of toe in in the backend. All of my GM cars needed alignment from the dealer. If you haven't had your alignment checked since purchase, I would consider doing that.
Wow now that you say that, It occurred while I was backing out and then turning to go on to the street. My wife described it as jumping and you called it hopping. Is there anything to worry about ?
Off topic, but should tire psi be higher…35-36?. Would this reduce hopping?
I have the Michelin Summer tires that came with the Z51 and the door says 30 PSI. However there seems to be a lot of latitude in what PSI is suggested my members on the board. I don't know that a higher PSI would reduce the unnerving shudder. I also have magnetic ride control and do not know if that may play into it.
I don't know any sure way of diagnosing if its its just the Ackermann effect that so many have suggested, or if its something else that could cause damage . I assume until I go to the dealer, the shudder in the rear tire when slowly backing up and turning on the driveway is the Ackermann effect. It has been cold, early morning and the driveway has been wet due to the heavy fog.
Off topic, but should tire psi be higher…35-36?. Would this reduce hopping?
No - the tires should remain at 30PSI. The Ackerman effect is a geometric effect caused by the wide front tires. The wheel hop will not hurt anything and will go away quickly at street speeds. Overinflated tires won’t stop it and they will become more inflated when the tires warm up.
12-29-2022, 03:38 PM
2021 Ball bearings or Suspension issue ?
