rikhek

I see there's current discussion mainly from newer owners. If anyone is interested here's a post I made some time back addressing the bending/breaking 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.

3 Z06ZR1

Number 7 is the biggest effect IMO.
The wheel itself has no support and open on one end. It has it own lever, A hit on the unsupported end and boom it bends. All C7 Z06
Corvette wheels forged or not will bend!

Carvin

I have thought about this. Sure would hate to spend $3-5K on forged only to have those bend too.

23/C8Z

Corvette is not the only vehicle to suffer from this issue. Use Google.

its low profile tires and almost NO sidewall.

as for the suspension settings? Like every thing you listed- that too plays a part (like the straw that broke the camel's back).

you cannot indiscriminately travel down any road, at any speed, anywhere, and just say "ah it's a new car it should be able to handle these potholes -railroad tracks - etc, etc" just the facts of Corvette life.

Mad Dog 24

I have punished my 2015 Z06 wheels with one of the earliest built Z's on the track, over stone roads, upstate NY pot holes and more now with 27K. Never an issue! Makes me wonder if GM changed manufactures some time in 15 and went cheap. I know this would be the very first time in a manufactures history this was done LOL!!

Z0HS1CK

it might be a later year z thing since my 16 doesn't suffer from pretty much ANY of the typical z issues I always read on this forum lol.

I went ahead and bought new wheels anyway and I got them today!! Cant wait to mount them. My perfect OEM wheels will be listed for sale soon lol

Ruderegime

negative
I purchased a 2016 ZO6 A8 earlier this summer with 12,000 miles on the clock and the tires were toast, so I took it to get some new tires and one of the front wheels was bent from the previous owner

Ruderegime

Maybe the brand new Michelin Pilot Sports will solve this issue?
Hopefully

Z0HS1CK

That might be previous owner neglect. Seems that most problems with these cars happen with the 17+ models lol

Carvin

Same. Bought my 2016 Z in December with 30K miles and found a cracked rear wheel during an inspection.

Road machine

How would you suggest they support the "unsupported end"??? You realize that is where the suspension and axels are right??? Exotic cars need to be treated as such. Even though these cars are very cheap for an exotic car, they have the same problems that come from ultra high performance cars.....and bent and damaged wheels are just one of the prices you pay. The light wheels on these cars are integral to the high performance. Unsprung weight has a huge affect on handling ride, and acceleration.

rikhek

I'm not suggesting there is a engineering solution for the "unsupported end". I do suggest this be addressed by not selling with ****, low strength cast wheels. The car should come with properly engineered, quality forged wheels from the factory. The General puts nice forged wheels on the Camaro and Cadillac but not the Corvette. Hard to justify their decision.

Road machine

We just replaced the forged wheel on My wife's 2017 Camaro SS vert. Much narrower wheel but still cracked when she hit a pothole. You wanna play you gotta pay.

rikhek

Of course forged wheels break and crack. If you race sport cars you're bound to experience this yourself. FACT is the failures occur on at a MUCH LOWER frequency than cast or rotary cast wheels. I've ripped the centers completely out of very expensive forged wheels racing but it doesn't happen on a regular basis. I've bent numerous OEM cast wheels on street cars. I've also bent forged wheels on street cars but again, at a MUCH lower frequency.

I really don't understand the point of your post.

Vegas Panton

Yes, I'm part of the C7 Z06 cracked/bent wheel club. I have read a lot of the threads dealing with this issue. Question? Did the C6 ZR1's have the same problems with their 19/20 inch wheels? From what I can tell, the wheels are basically the same dimensions with a different spoke design. I have seen the Corvette Driving School at Spring Mountain using C6 ZR1 wheels on C7 Z06's. Several people in our club have C6 ZR1's and have never had an issue with their wheels.

tertiumquid

In the end, I think the problem has a pretty simple cause and it's compounded by the OEM cast wheels. The culprit is the hard side wall of the run-flats. Think about the obvious mechanics of the tire/wheel striking a ridge or pothole at speed. The shock is transferred directly to the wheel rim edge because the tire sidewall has virtually no give and the power of the impact is immense. I agree with many that the problem can still occur with stronger forged wheels but much less so. The only real way to avoid that impact transfer to the wheel is to use a tire that has some ability to absorb the shock of impact. That means a non run-flat, like a Continental or similar. If you're using your car for the street only, this is the best way to minimize the problem with our cars. And, to be fair, a lot of criticism that's directed at the ZO6 tire/wheel problem is the same that occurs with BMW's, Audi's, Ricer's etc.,... any car with these extreme low profile run-flat tires experiences the same problem. Certainly, though, the cheap GM Chinese or Mexican OEM cast wheels make the whole thing far worse than it should be.

X25

Culprit is simple, weak wheel design; period. The tire sidewalls, suspension design, etc. are all by design of the car, and engineers should have made sure the wheels would survive regular use.

IIRC, it was explained that every GM wheel go through a certain torture test, where they're driven through a very tough test track 1000 times, after which wheels are inspected for any issue. For sports cars, the test duration is doubled. These wheels would definitely fail the test. Something went wrong and stop finding excuses : )

tertiumquid

I'm inclined to agree with you on the wheel quality. However, if you consider the problem is not limited to Corvettes, then there's obviously something else at work, too. The other car forums that use the same configuration of wheels and RF tires are full of similar stories. It's simple physics: in a collision of two objects, the weakest will give. Apparently, using RF's with these wheels is similar to a early 20th century truck that had solid rubber tires...

CW4L

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Z0HS1CK

This.

It's the combination of not the strongest wheel paired with what i call "hockey pucks", which is what the run flats are. Might as well drive a little tikes car with the hard *** plastic wheels. Same thing lol