6 Bent OEM wheels, time for a change - help requested
10-08-2018, 04:51 PM
#41
Pro
Thread Starter
Wheel insurance folks are playing some games and delaying the inevitable replacement of the OEM wheels. I don't necessarily blame them after the 3 claims (this is the 4th technically) so far but man am I happy to be moving on to some new, quality hardware.
10-08-2018, 04:59 PM
#42
If anyone is interested here's a post I made some time back addressing the bending of the OEM wheels. I did a real quick qualitative failure analysis identifying the many contributing factors:
Causal analysis dictates accidents/undesired events are NEVER the result of a single cause. The theory in failure analysis is the "Principle of Multiple Causes". Specific to bending wheels on the C7Z there are a good number of multiple causes. For a "bad thing" to happen all of the multiple causes are encountered/occur simultaneously. Several of the many multiple causes that pop to mind relative to the topic at hand:
1. Thin sidewall on low profile tires.
2. Stiff sidewall construction.
3. Very wide wheels resulting in a large moment arm at the outside edge of the wheel.
4. Very tall (i.e., 19" and 20") wheels resulting in minimal structural support at the outside of the wheel. large moment arm.
5. Very wide wheels resulting in minimial structural support/strength along the entire barrel.
6. Thin, lightweight wheels.
7. Inadequate mechanical integrity/strength in wheel design.
8. Stiff suspension regardless of what mode you're running.
9. High speed shock compression is very slow to provide performance.
10. Limited shock travel for handling performance.
11. Roads with surface irregularities.
12. Etc, etc, etc.
Dig deep back into your grey matter to the days of Physics classes and the Conservation of Energy principle. Specifically, "energy can neither be created nor destroyed". The energy has to go somewhere when an event occurs. Typically the weakest part of the system as a whole absorbs/dissipates most of the energy.
Test question: Where is the weakest part of the system in the case of a car traveling on imperfact roads at somewhat high speeds with a stiff shock/spring suspension with relatively short shock travel utilizing tall, wide wheels and tires with stiff, thin sidewalls?
Winner, winner, chicken dinner...
Rick
P.S. MUCH too much discussion and significance is being placed on what suspension setting is being used. It really doesn't matter as it's a relatively MINIMAL contributing factor.
Causal analysis dictates accidents/undesired events are NEVER the result of a single cause. The theory in failure analysis is the "Principle of Multiple Causes". Specific to bending wheels on the C7Z there are a good number of multiple causes. For a "bad thing" to happen all of the multiple causes are encountered/occur simultaneously. Several of the many multiple causes that pop to mind relative to the topic at hand:
1. Thin sidewall on low profile tires.
2. Stiff sidewall construction.
3. Very wide wheels resulting in a large moment arm at the outside edge of the wheel.
4. Very tall (i.e., 19" and 20") wheels resulting in minimal structural support at the outside of the wheel. large moment arm.
5. Very wide wheels resulting in minimial structural support/strength along the entire barrel.
6. Thin, lightweight wheels.
7. Inadequate mechanical integrity/strength in wheel design.
8. Stiff suspension regardless of what mode you're running.
9. High speed shock compression is very slow to provide performance.
10. Limited shock travel for handling performance.
11. Roads with surface irregularities.
12. Etc, etc, etc.
Dig deep back into your grey matter to the days of Physics classes and the Conservation of Energy principle. Specifically, "energy can neither be created nor destroyed". The energy has to go somewhere when an event occurs. Typically the weakest part of the system as a whole absorbs/dissipates most of the energy.
Test question: Where is the weakest part of the system in the case of a car traveling on imperfact roads at somewhat high speeds with a stiff shock/spring suspension with relatively short shock travel utilizing tall, wide wheels and tires with stiff, thin sidewalls?
Winner, winner, chicken dinner...
Rick
P.S. MUCH too much discussion and significance is being placed on what suspension setting is being used. It really doesn't matter as it's a relatively MINIMAL contributing factor.
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Z0HS1CK (10-08-2018)
10-08-2018, 05:41 PM
#43
Safety Car
Gee, as I was reading through you long list of causal factors I was flabbergasted that the most important factors were left off the list. Your list neglected to mention poorly designed wheels incapable of withstanding the structural loads they would operate within and also poor manufacturing and quality control measures. GM - have you not heard of 6 Sigma? I don't recall Corvette wheels ever failing in previous generations like they appear to be in this current generation. When GM and other vendor suppliers have created an industrial culture where cutting corners to make a few extra pennies on every wheel manufactured, poor performing, and unreliable products will result. Should consumers be surprised.
5. Very wide wheels resulting in minimal structural support/strength along the entire barrel.
6. Thin, lightweight wheels.
7. Inadequate mechanical integrity/strength in wheel design.
I didn't go through the exercise of identifying corresponding Basic/Root Causes as I'm not getting paid for my time ;-) I disagree with your statement, "poor manufacturing and quality control measures". There is nothing wrong with the manufacturing and quality control measures. They're being delivered to GM exactly as designed and spec'd. Therein lies one of the problems...
The money factor is one of the basic/root causes directly resulting in the pitiful design. Further, I think money might have also played a roll in the idiotic decision by GM to put cast wheels on the car instead of forged. Hell, even the Camaro gets forged wheels!!!
Last edited by rikhek; 10-08-2018 at 05:45 PM.
10-08-2018, 05:59 PM
#44
Gee, as I was reading through you long list of causal factors I was flabbergasted that the most important factors were left off the list. Your list neglected to mention poorly designed wheels incapable of withstanding the structural loads they would operate within and also poor manufacturing and quality control measures. GM - have you not heard of 6 Sigma? I don't recall Corvette wheels ever failing in previous generations like they appear to be in this current generation. When GM and other vendor suppliers have created an industrial culture where cutting corners to make a few extra pennies on every wheel manufactured, poor performing, and unreliable products will result. Should consumers be surprised.
Not to mention some have reported the C7 grand sport wheels to be "stronger" than the z06 wheels.
But if you're going to buy a different set of wheels to prevent your current wheels from bending or cracking, might as well go aftermarket.
Which is what i did. And that's coming tomorrow!! Hooray!
10-10-2018, 09:59 PM
#46
Use them as planters in the garden. It would be a step up from a tractor tire...
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Z0HS1CK (10-11-2018)
10-10-2018, 10:17 PM
#49
Don't bother with any wheel repair. They'll only bend and/or crack again. All you'll do is waste your money and get more aggravated.
10-11-2018, 01:18 AM
#50
2 bent rims here 🙋🏼*♀️
I was told today that GM changed vendors... can anyone verify that?
I was also also told the rims have to go back for core charge.
Its been 2 months and I have about 5000 miles on bent rims (yes it’s a daily driver) and I’m ready for my ordered rims. By the time I get them I’m gonna need new tires.
I was told today that GM changed vendors... can anyone verify that?
I was also also told the rims have to go back for core charge.
Its been 2 months and I have about 5000 miles on bent rims (yes it’s a daily driver) and I’m ready for my ordered rims. By the time I get them I’m gonna need new tires.
10-11-2018, 01:32 AM
#51
That would be great news jen. Did you get that info about a new wheel supplier from a good source?
10-11-2018, 06:46 AM
#52
10-11-2018, 06:06 PM
#54
One can only wonder what they expect to do with the returned core. These things are unfixable. Don't buy any GM replacement wheels...all you'll get is new junk. If you want to really fix the problem go to decent forged wheels (around $4K) and dump the run-flats. Unfortunately, that's an expensive move for a lot of folks but it's really the only way to get away from the problem for good.
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Z0HS1CK (10-11-2018)
10-12-2018, 09:47 AM
#56
Safety Car
I have owned quite a few sports cars over the years including all other generation vettes. Everyone of them had wheel issues (well not the C1 C2 or C3 vettes.The worst was a Mercedes CLK 550. I went through three complete sets of wheels on that one. This is just a fact of life with low profile tires and wide wheels. One thing to be very careful about when replacing wheels is weight. Un-sprung weight has a huge impact on handling and performance. I remember my C5 Z06 was so awesome to drive, then I drove a buddies car that he said seemed really slugish and not fun to drive. I drove it and it was a world of difference. We swapped wheels and it was like night and day. He had bought the car with aftermarket chrome wheels. He went out and bought OEM wheels and that was the cure. If you are using your car as a daily driver, then you should look for the strongest wheel and sacrifice performance, but if you can live with the OEMs you will preserve the performance....just look out for the bumps.
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Carvin (10-12-2018)
10-12-2018, 09:55 AM
#57
Pro
Thread Starter
3 replacement wheels are getting on the car today. I will have to drive carefully until the new metal gets here.
As for wheel strength, I chose the track rated style of wheel from Forgeline so that will hopefully help. I do/will track the car so that made sense as well. Time will tell!
And I'm going to see if I can get one of the old wheels to make that hose reel I mentioned. I think I recall them saying it was a $50 core charge which isn't terrible. I will see....
As for wheel strength, I chose the track rated style of wheel from Forgeline so that will hopefully help. I do/will track the car so that made sense as well. Time will tell!
And I'm going to see if I can get one of the old wheels to make that hose reel I mentioned. I think I recall them saying it was a $50 core charge which isn't terrible. I will see....
Last edited by blackbirdws6; 10-12-2018 at 09:55 AM.
10-12-2018, 04:23 PM
#58
Pro
Thread Starter
Picked up the car and man, is she nice and smooth again. I didn't get a spare wheel to play with as they wanted too much for the core. No biggie. Now I need to carefully drive the car until the new wheels get here.
10-12-2018, 04:46 PM
#59
Melting Slicks
Thanks
10-12-2018, 08:21 PM
#60
Team Owner
I pull the stock wheels right away and go for the cups that have been around since 2009 they have have no bending issues plus they are lighter than the stock z06 wheel.
I'm happy i don't have an issue with bending wheels and I drive across country. Leaving in the AM to go over 1500 miles