Wheel Problems
Safety Car
Joined: Mar 2018
Posts: 4,754
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I have 15,000 miles on my 19 GS. Use it just as a daily driver, no track. So far no problems with the stock OEM wheel. However, I really expect it is just a matter of time. I have a rainy day fund if the cracks begin to develop. I closely monitor tire pressure every time I drive the car. If I ever notice a precipitous drop in any tire pressure I will check for a flat but also check for any crack development on the inner barrel rim where cracks will form if present. These wheels are structurally deficient. Regarding OEM on the track - absolutely not. They are not safe at those speed. Wheels will be most heavily stressed structurally going in and coming out of corners. Flow formed forged wheels are marginally better as the inner hub and wheel spokes are actually cast aluminum. Only way to go is mono-block forged.
Thread Starter
Melting Slicks
Joined: Apr 2004
Posts: 2,773
Likes: 138
From: cyberspace NY
From the pictures posted, all the damage looks like impact damage. Like what I typically see from NYC pot holes. That's why I figured OEM wheels should do well on track, where there are no pot holes. and surely they have been tested at speed.
Safety Car
Joined: Mar 2018
Posts: 4,754
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The outward face (the side you see) of the OEM wheel is the strongest structural part of the wheel. You shouldn't expect wheel cracks there unless you hit a wall at speed. All Corvette OEM wheel failures are occurring on the inside rim face. Every one of them. This is the part of the wheel which is unsupported, the mechanical stresses are highest there in all high speed turns, the barrel depth has an exceedingly deep offset as well as the **** poor design of the OEM cast aluminum wheels make tracking OEM Corvette wheels on a wide body Corvette a crap shoot. Hope you have a good track insurance policy and your life insurance premiums are up to date.
Safety Car
Joined: Mar 2018
Posts: 4,754
Likes: 1,650
It is the inner portion of the wheel on the opposite side of the turn (eg, left wheel on a right bending turn) that sees the highest loads. The outer wheel (left) is always taking the higher loads in this example. Given that the inner portion of the wheel is unsupported there, it will experience the highest stress. Think about it some more. I think you will come around to agree. It is for this reason why you do not have to hit a pot hole to suffer a crack (from stress damage) on a wheel. There are very large bending stresses present on the inner wheel in turns.
Last edited by MMD; Nov 8, 2020 at 10:57 PM.
Safety Car
Joined: Mar 2018
Posts: 4,754
Likes: 1,650
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Burning Brakes
Joined: Nov 2017
Posts: 800
Likes: 326
It'll be a while, as they are buried in our storage shed under tons of rubble...waiting for the eventual recall...LOL! From my memory, my cracks were middle of the barrel, although they could have been longer than I noticed.
Safety Car
Joined: Mar 2018
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Le Mans Master
Joined: Oct 2005
Posts: 7,088
Likes: 1,829
From: Metro Detroit Michigan
It is the inner portion of the wheel on the opposite side of the turn (eg, left wheel on a right bending turn) that sees the highest loads. The outer wheel (left) is always taking the higher loads in this example. Given that the inner portion of the wheel is unsupported there, it will experience the highest stress. Think about it some more. I think you will come around to agree. It is for this reason why you do not have to hit a pot hole to suffer a crack (from stress damage) on a wheel. There are very large bending stresses present on the inner wheel in turns.
Safety Car
Joined: Mar 2018
Posts: 4,754
Likes: 1,650
I agree. It's the other wheel that is loaded. You can find many pics on the Internet where a track car is actually lifting off the ground on the inner wheel. The outer wheel though is heavily loaded at this time. On apparently some C7 OEM wide body wheels the loads are high enough to either bend or even crack a wheel over time.
Burning Brakes
Joined: Nov 2017
Posts: 800
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Le Mans Master
Joined: Oct 2005
Posts: 7,088
Likes: 1,829
From: Metro Detroit Michigan
So far, none of my wheels are bent (as far as I know), and we have some pretty rough roads in Michigan, with all the freeze-thaw cycles.
From what I have read over the years about the various experiences with the C7 Z06 and the Grand Sport wheels, I suspect that there are different batches, or maybe even different suppliers, furnishing different properties.
From what I have read over the years about the various experiences with the C7 Z06 and the Grand Sport wheels, I suspect that there are different batches, or maybe even different suppliers, furnishing different properties.
Tech Contributor
Joined: Oct 1999
Posts: 41,058
Likes: 9,817
From: Charlotte, NC (formerly Endicott, NY)
I have used my wheels on track several times. The biggest issue that I have had is due to the complicated spoke design they are very hard to keep clean. Racing brake compounds can be very abrasive and when brake rotors are throwing superheated gases through the spokes the dust just cooks into the paint. Since there is so little room to apply cleaning and polishing materials to them the wheels tend to have a cloudy look to them.
As far as physically damaging the wheels they held up well during the 3 days I did use them on track. They weren't damaged by running the rumble strips at speed. I have about 16K miles on the car and about 10K miles on the wheels since I use 18 inch track wheels when on track unless it is raining or I have corded one of my track tires. That is when the street wheels/tires are put on the car.
Bill
As far as physically damaging the wheels they held up well during the 3 days I did use them on track. They weren't damaged by running the rumble strips at speed. I have about 16K miles on the car and about 10K miles on the wheels since I use 18 inch track wheels when on track unless it is raining or I have corded one of my track tires. That is when the street wheels/tires are put on the car.
Bill
Thread Starter
Melting Slicks
Joined: Apr 2004
Posts: 2,773
Likes: 138
From: cyberspace NY
It is the inner portion of the wheel on the opposite side of the turn (eg, left wheel on a right bending turn) that sees the highest loads. The outer wheel (left) is always taking the higher loads in this example. Given that the inner portion of the wheel is unsupported there, it will experience the highest stress. Think about it some more. I think you will come around to agree. It is for this reason why you do not have to hit a pot hole to suffer a crack (from stress damage) on a wheel. There are very large bending stresses present on the inner wheel in turns.
Safety Car
Joined: Mar 2018
Posts: 4,754
Likes: 1,650
It will not occur over the course of 1 track session. It will depend on how hard you are taking the turn (g's), how sharp is the turn, and how fast are you going. These parameters will determine the loading on the wheel. All OEM wheels will not be affected but cracking/bending will definitely be present on the some of the more marginally manufactured wheels. The first indication will more than likely be an out of round condition. Driving with an out of round wheel, if unchecked, will eventually lead to a crack developing in the wheel. Not all OEM wheel fail in this manner. There are design variances that makes a certain percentage of the wheels slightly stronger and some slightly weaker than the norm. If you're a track rat you can try taking off the left front wheel and test with your dial gage to make sure the wheel is near perfectly roundness (no run outs). After the track session take the same wheel off and see if the wheel is still perfectly round. This little experiment only need be performed on OEM wheels.
Last edited by MMD; Nov 9, 2020 at 07:09 PM.