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I'm looking at wheels still and may go with non OEM / replicas. I've seen JWL/VIA and TUV. What do these mean ? Do they guard against cheap wheels that crack / bend easily ? Can a mfr cheat any of these ?
JWL, which is an acronym for Japanese wheel light alloy, is a Japanese std. Each manufacturer who uses the stampings, is expected to voluntarily accomplish the testing standards, but there is no independent inspection of each wheel. VIA is a Japanese organization that audits for compliance with those standards. TUV is a German standard.
Is it possible to cheat, certainly, but it is illegal to use those stamps unless there is documentation that a manufacturer has tested and passed the certification criteria for JWL, TUV or both. VIA is supposed to mean that a wheel manufacturer has been audited at some point.
The purpose of the standards is to ensure that they meet a certain wheel safety standard, and theoretically should be more resistant to damage, of higher quality, and hence safer. That doesn't mean a nasty pothole won't take out a JWL/TUV-certified wheel even it's legit.
However, as we all now, cheating goes on all the time, and perps don't always get caught. It's not a guarantee, but it's better than no standard at all.
Well, yes and no. If a wheel manufacturer gets caught with JWL/TUV/VIA stampings without proof that they are following the actual certification standards, there are legal repercussions. Thus, most wheel manufacturers are not willing to take that risk.
You asked if it's possible to cheat, and the answer is yes. However, generally speaking I don't think that's common. But yes, an established, name-brand, wheel manufacturer is very unlikely to cheat.
There aren't a lot of wheel manufacturing plants, and most make wheels for both well known brands, as well as off-brands. JWL/TUV standards are really minimum standards, which most big plants meet. The most expensive forged monoblock wheels far exceed JWL/TUV standards.
Has there been an actual engineering comparison of the quality of non-OEM wheels vs OEM wheels? It would seem to me that OEM wheels designed/selected for the Corvette would be top notch.
You can't say they are "top notch," but they are adequate and safe.
"Top notch" wheels are forged monoblock wheels, which are carved out of single blocks of forged aluminum. They are the lightest and strongest wheels available and usually cost at least 3X what C7 OEM wheels cost.
You can't say they are "top notch," but they are adequate and safe.
"Top notch" wheels are forged monoblock wheels, which are carved out of single blocks of forged aluminum. They are the lightest and strongest wheels available and usually cost at least 3X what C7 OEM wheels cost.
What exactly does a that single block of forged aluminum look like before machining? Just trying to understand the process. Thanks.
^^^
See that often on Chip Foose TV show (and some other car shows.)
He designs a wheel and like some aircraft parts, that large round block, about the width of the wheel, is put in a CNC machine and some time later after multiple tools make 80+% aluminum chips emerges a finished wheel!
Found this pic of a more efficient manufacturing process than the one-of custom wheel manufacture.
Stilll makes much more aluminum scrap than finished product.
I didn't know spin forging was part of the monoblock forging process. I have read Thai spin / rotary forging is used on cast wheel castings. I was under the impression ther forged monoblock 6061 was CNC constructed.
JWL, which is an acronym for Japanese wheel light alloy, is a Japanese std. Each manufacturer who uses the stampings, is expected to voluntarily accomplish the testing standards, but there is no independent inspection of each wheel. VIA is a Japanese organization that audits for compliance with those standards. TUV is a German standard.
Is it possible to cheat, certainly, but it is illegal to use those stamps unless there is documentation that a manufacturer has tested and passed the certification criteria for JWL, TUV or both. VIA is supposed to mean that a wheel manufacturer has been audited at some point.
The purpose of the standards is to ensure that they meet a certain wheel safety standard, and theoretically should be more resistant to damage, of higher quality, and hence safer. That doesn't mean a nasty pothole won't take out a JWL/TUV-certified wheel even it's legit.
However, as we all now, cheating goes on all the time, and perps don't always get caught. It's not a guarantee, but it's better than no standard at all.
A lot of the OEM and replica wheels are made in China. GM provides the manufactures the specifications required for the wheels. If you pick a well known replica wheel manufacturer, who has been in business for a long time, you probably can't go wrong.
I can't confirm it, but a seemingly reliable source here stated that both the Z51 OEM wheels and the reproductions of same, were at one time manufactured in the same Chinese factory. The reproductions also have the JWL, TUV, and VIA stampings.
I think they were later sourced to a plant in Mexico.
I didn't know spin forging was part of the monoblock forging process. I have read Thai spin / rotary forging is used on cast wheel castings. I was under the impression ther forged monoblock 6061 was CNC constructed.
Foosh has answered all of the questions well in this thread, but to add to this question:
Spin forging, or rotary forging on a low pressure cast wheel is just a supplemental process to shape the grain structure of the alloy on the barrels (only) closer to that of a true forged wheel.
In this instance, the wheel is still a low pressure cast wheel (the face) And the barrel only is spun forged to increase strength versus a cast barrel. Do not be fooled, you are still getting a low pressure cast wheel, but the barrel is spun very similar to what is done on a forged monoblock wheel. The issue for me is that wheels typically fail at the faces more, not as much at the barrel.
Think of it as a "low pressure cast wheel 2.0"
That being said, although the spinning process itself can vary among manufacturers, the general process is, in fact, similar to the similar step during the forged monoblock process. Think of it this way:
Forged face/spun barrel
Pressure cast face/spun barrel
Originally Posted by juanvaldez
I always thought that JWL mark was a manufacturers' mark.
Nope it's a Japanese wheel standard second to TUV in strictness.
Has there been an actual engineering comparison of the quality of non-OEM wheels vs OEM wheels? It would seem to me that OEM wheels designed/selected for the Corvette would be top notch.
OK first I want to thank everyone for your questions and responses. Very much appreciated. Back to my original question above, is there engineering data available to compare OEM vs non OEM wheels? After reading and seeing photos of the shattered wheel in the "OUCH" thread and not knowing if that is an OEM wheel or knockoff, I am concerned.
OK first I want to thank everyone for your questions and responses. Very much appreciated. Back to my original question above, is there engineering data available to compare OEM vs non OEM wheels? After reading and seeing photos of the shattered wheel in the "OUCH" thread and not knowing if that is an OEM wheel or knockoff, I am concerned.
Define "engineering data"...?
Like exact dimensional specs via CAD models? FEA analysis results?
Exact types of molds and low pressure casting methods used? Exact pressure used on the mold? Data on the factories equipment? Sources and MTR's on the alloy used? QA/QC procedures?
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Wheel Certification : What's it mean ?
