robertbruce

Are cracked rims covered under warranty?

JerryU

^^^
Nope! GM says it’s due to poor roads, hitting potholes etc.

Many forum members don't accept the Chief Corvette Engineers explanation for the issue that he posted on the Forum. Thought I'd post it here.

When there was only a Z06 with wide wheels the issue was not nearly as visible as now as with the introduction of the Grand Sport over half the C7's sold have wide wheels. Probably why he says their "wheel damage rate" so their statistics are probably about the same percentage. It's no doubt a higher number than previously.


"Your question raises a number of issues which I will try to address. I would like to start with your comment about “Chinese wheels”. No Grand Sport wheels come from China. In fact, the majority of our wide Corvette wheels (those most susceptible to bending) are produced by a company named Ronal which is based in Switzerland and manufactures wheels here in North America. (Note, my Grand Sport wheels say made in Mexico and Speedline, a Ronal trademark.) A couple of our low-volume Z06 wheels do come from China, but regardless of where they are made, all Corvette wheels are built and tested to GM and Corvette specific standards.

Wheel design is very complex and has to balance many attributes. Everyone wants beautiful wheels, but they also have to be stiff for good handling, strong to resist road damage and low weight. Un-sprung mass is the most important mass in the vehicle. You want light wheels because they enable the suspension to keep the wheel tracking the road surface and you want low rotating inertia because it affects how quickly the car can accelerate and brake. High mass wheels not only hurt handling, but they drive additional mass in the rest of the car. When you hit a pothole, high mass wheels generate higher loads into the suspension and body. As wheels get wider to accommodate wider tires, all these challenges are increased. For these reasons we spend a huge amount of engineering resources on optimizing wheels. We design wheels to withstand extreme pothole loads and test them on high speed laboratory equipment that can simulate the entire life-cycle of the vehicle. I have heard from some people that there is a theory that running the car in sport or track can contribute to damaging a wheel. That is not true.

People are often surprised that a wheel can be bent or cracked without any visible damage to the tire or obvious scratches on the wheel. Our tires have very stiff sidewalls for great handling and the ability to drive the car with no tire pressure whatsoever. As a result they can transfer loads to the wheel without being damaged themselves. A frequent sequence of events is that a wheel gets bent by a road hazard but the damage is initially almost undetectable to the driver. Maybe the driver notices a little more vibration, but many times not if the wheel is only slightly out-of-round (just a millimeter or two). A wheel that is not perfectly round puts stress in the rim that varies with every wheel rotation. Over time fatigue cracks can form after thousands or even millions of cycles. The wheel doesn’t look any different but begins to leak air at the rim. Since it is hundreds or thousands of miles after the damaging event, the driver often can’t remember hitting anything that would justify a crack in the wheel. I have actually experienced this myself. Obviously the wheel has to be replaced since there is no way to reliably repair a rim crack. Tires should be inspected carefully after being dismounted. Sometimes there is no damage on the outside but a blister, bulge, tear or crack can be visible on the inside. With safety as the top priority, any defect would justify a tire replacement.

The question postulates a “rash” of wheel failures. Our field data does not suggest a recent significant increase in the wheel damage rate on our cars. (Note he carefully says damage rate! Bet this had to pass though several GM attorneys before it was sent to be published!) There may be more reports of damage than historically, but, between the Z06 and Grand Sport, we are selling lots more wide-wheel cars than we ever have before. More cars on the road means more chance of hitting something in the road.

We do keep a keen eye on what our customers are experiencing in the field. I don’t know where you live, but the roads here in Michigan seem to be getting worse every year. I can promise you we will continuously improve our designs and validation procedures based how the world is changing.

TNSQUIRE

Only if you purchased the tire and wheel warranty

Vetteman Jack

It’s a shame that owners are having to deal with the cracked/bent wheels.

Avanti

"Blah, blah, blay." Thank you, GM.

The reality is that they are, apart from anything else, wheels AND tires inappropriate to many, many typical US highways lots (if not most) of us drive on a regular basis and GM doesn't give a flyin' fig. Optional "real world" factory options would both make good-sense and be appreciated.

trumanjd1

and...hoping the replacements are available..if you want to gamble with the same quality of wheel that put you into this predicament
If you are keeping your C7..it may be a wise move to purchase and better quality FORGED wheel that vendors here are offering...do your homework..before..if you decide to go that route.

robertbruce

Trading the car when I get the C8.(# 2 on the list of a large dealer). Do you know of any aftermarket wheel dealers that sell the chrome Z06 rim if I can't get the right one from GM?

KenHorse

Driving down to SoCal in a couple of weeks

Fingers, toes, everything crossed

TNSQUIRE

I feel the same way. I'm heading to Vegas and concerned about these wheels.

Carvin

Tire Rack and Mid America Motorworks sell replicas. I imagine those would not have the Z06 logo.

z51vett

House of wheels in Florida vendor on here cheaper than dealer factory and reproduction
z51vett
Doug

DALE#3

What a Kick In The Nuts! Worrying if your $70k plus car breaks a rim on a God Dam Trip!!
You will hit a expansion joint or a hole.I swear every dam time the car hits something.
Ohh ****! That one wasn't good..No matter how precise you aim this goddame POS Wheels.
Makes me Mad as Hell.Screw it.What can you do...

JerryU

^^^
With now over ~15,000 C7s/year sold having wide wheels on the Grand Sport/Z06/ZR1, yep some will bend and crack as they always can with very wide wheels. Some of the comments folks make re the Grand Sport wheels are just wrong!

First they are not cast or made in China! Frankly nothing wrong with cast wheels- worked fine on my S10 truck and off-road CJ5 Jeep Renegade, they are just heavy for wide, performance wheels! The Grand Sport and most Z06 and Z51 wheels are made by the German/Swiss based Ronal. My Grand Sport wheels are stamped "Made in Mexico and Speedline" a Ronal tradename (Tadge in his Forum post also said the wheels were made by Ronal.)

The first C7 Bash showed a short video of the Z51 wheels being made with flowforming in their plant in Mexico. As I recall it mentioned the base C7 wheels were cast. About 2 to 3 minutes in on the video below shows a similar Flowforming (a Ronal name) process used to make the wheels. There is a lot of cold work that makes the thin rim strong. Although they probably start with a cast blank this is what Discount Tire says about the process.

Rim-rolled (Also called, Flow Forged, Flowforming, etc)
Rim-rolled wheels are made using a low-pressure casting that is then spun on a specialized machine. This machine heats the outer portion of the cast section and uses rollers to shape the rim to achieve the desired width and shape. The combination of the applying heat and pressure then spinning the material, creates a rim with strength similar to a forged wheel at a lower price point. Resulting in a light and strong wheel at a reasonable cost, the rim-rolling process is commonly used to produce OEM wheels for limited edition high performance vehicles.

Here is a good video discussing Ronal. Wide Corvette Wheel "rims" could be too thin for rough environments but so could "forged wheel rims."

thompstl1

The factory stock wheels on my 2018 Carbon 65 Z06 would appear to be made in China (and the Carbon 65 Z06/Grand Sport share the same wheels); at least I assume that's what CHINA stamped on the back-side indicate.

Regardless of where they are made, they are not suitable for "real world" driving in my view. Having 3 bent wheels with less than 9,000 miles on them is ridiculous when I've not driven over anything at all substantial enough to even consider bending a reasonably built wheel.

JerryU

Tadge does say in his post; "No Grand Sport wheels come from China. A couple of our low-volume Z06 wheels do come from China, but regardless of where they are made, all Corvette wheels are built and tested to GM and Corvette specific standards."

Looks like you have what Tadge refers to as a "low-volume" Z06 wheel. Perhaps the "special wheel" that comes with the Carbon Edition model C7.

Have no idea how it's constructed. IMO the Ronal "Flowformed" wheels (the way my Grand Sport wheels are made in Mexico, as they are labeled) is a good manufacturing process.

robertbruce

I couldn't figure out what the problem was. I get in the car and the dash tells me my passenger side rear wheel is low. I always plug my own tires so I tried like hell to find the nail in the tire by having my wife drive real slow while I looked for the nail. I couldn't find one so I jacked up the car and pulled off the wheel and there it was. Cracked rim. Very very slow leak so hard to tell how long it has been like that.,

Gearhead Jim

Although a forged wheel can be somewhat stronger than cast, the maker of the forged wheel may simply reduce the thickness of the wheel to save weight and you end up with a wheel which is lighter but not stronger.
Or if they do use the extra strength to make a more durable wheel, you can still bend it if you hit a big enough bump.

I would be very reluctant to spend the big bucks for high quality forged wheels just in the hope that they might hold up better than the factory version.

Zo62018A8

Why didnt you get the Tire n Wheel protection plan from the finance manager when you were doing your paperwork? It would have paid for itself just by that one claim.

robertbruce

I have never talked to a finance manager when buying my Corvettes. I have never heard of this wheel plan.

Zo62018A8

Im amazed

http://www.fidelitywarrantyservices....ard-protection