Cracked 5 spoke rim
Melting Slicks
Joined: Mar 1999
Posts: 3,212
Likes: 167
From: Rochester Hills Michigan
Re: Cracked 5 spoke rim: Update (Gearhead Jim)
An engineer told me that chrome plating tends to weaken the underlying metal by a process called "hydrogen embrittlement". In theory, the problem can be solved by baking the hydrogen out of the metal, if the shop is really good. In practice, I try to avoid chromed parts for anything where strength is important.
In steel...not aluminum, H2 embrittlement can happen. I deal with stuff as a metallurgist every day. Cracks in chrome plating are the problem. These lead to fatigue cracks. Cracks are normal for the chrome process.
Team Owner
Joined: Sep 2000
Posts: 25,019
Likes: 2,714
From: Far NW 'burbs of Chicago
St. Jude Donor '13
Re: Cracked 5 spoke rim: Update (RedC5)
Joe-
Thanks for the info. I think you are saying that the cracking/stress riser problem will happen with any metal, not just aluminum. True? How about what is commonly called hard chrome, the stuff that usually has a slightly frosted appearance- does it also have cracks?
Thanks for the info. I think you are saying that the cracking/stress riser problem will happen with any metal, not just aluminum. True? How about what is commonly called hard chrome, the stuff that usually has a slightly frosted appearance- does it also have cracks?
Instructor
Joined: Sep 2000
Posts: 155
Likes: 0
From: Chatsworth, Ca. 91311
Re: Cracked 5 spoke rim: Update (BlackOps)
I just noticed a crack in my Y2K factory polished wheels last week. It does not go all the way through like yours but it is a hairline crack in the left rear wheel on one of the spokes. I've never hit anything with it and the wheel has no other damage on it. I've had it at button willow about 4 times for a total of 12 hours of track time. Its a bummer but it is a good excuss to upgrade the wheels.
The Chroming theory here wont work since these are factory polished wheels. It may be that the metal is fatiguing after two years. The Y2K and above wheels don't have a lot of material to work with.
The Chroming theory here wont work since these are factory polished wheels. It may be that the metal is fatiguing after two years. The Y2K and above wheels don't have a lot of material to work with.
Melting Slicks
Joined: Mar 1999
Posts: 3,212
Likes: 167
From: Rochester Hills Michigan
Re: Cracked 5 spoke rim: Update (Gearhead Jim)
Jim
Yes the stress riser is what kills the fatigue life. I've seen some parts fatigue out less than half the fatigue life compared to non chrome. Hard chrome can have cracks too. See second set of photos for example http://www.techmetals.com/pdfs/TM105-20020506.pdf. Hard Chrome Techmetal 105. There is a chrome plating process that is more expensive called "crack free" chrome which I has minimal cracking (non-continuous to base metal) but the term is used loosely since it is not truely crack free.
[Modified by RedC5, 10:31 PM 7/10/2002]
Yes the stress riser is what kills the fatigue life. I've seen some parts fatigue out less than half the fatigue life compared to non chrome. Hard chrome can have cracks too. See second set of photos for example http://www.techmetals.com/pdfs/TM105-20020506.pdf. Hard Chrome Techmetal 105. There is a chrome plating process that is more expensive called "crack free" chrome which I has minimal cracking (non-continuous to base metal) but the term is used loosely since it is not truely crack free.
[Modified by RedC5, 10:31 PM 7/10/2002]
Melting Slicks
Joined: Mar 1999
Posts: 3,212
Likes: 167
From: Rochester Hills Michigan
Re: Cracked 5 spoke rim: Update (shaheen)
I just noticed a crack in my Y2K factory polished wheels last week. It does not go all the way through like yours but it is a hairline crack in the left rear wheel on one of the spokes. I've never hit anything with it and the wheel has no other damage on it. I've had it at button willow about 4 times for a total of 12 hours of track time. Its a bummer but it is a good excuss to upgrade the wheels.
The Chroming theory here wont work since these are factory polished wheels. It may be that the metal is fatiguing after two years. The Y2K and above wheels don't have a lot of material to work with.
The Chroming theory here wont work since these are factory polished wheels. It may be that the metal is fatiguing after two years. The Y2K and above wheels don't have a lot of material to work with.
Not good.....that is a fatigue crack if it is not a production forging defect lap or fold. Take it to the dealer for warranty replacement.
Team Owner
Joined: Sep 2000
Posts: 25,019
Likes: 2,714
From: Far NW 'burbs of Chicago
St. Jude Donor '13
Re: Cracked 5 spoke rim: Update (RedC5)
Joe-
The link to the photos did not work for me, but I get the idea.
Not good to hear about the polished wheel cracking, that should be better stuff.
The link to the photos did not work for me, but I get the idea.
Not good to hear about the polished wheel cracking, that should be better stuff.
Thread Starter
Melting Slicks
Joined: May 2001
Posts: 2,186
Likes: 7
From: Evansville, IN The GOCC, rebels without a clue.
St. Jude Donor '06
Re: Cracked 5 spoke rim: Update (Gearhead Jim)
This is good stuff for review. I'm passing on chrome rims from now on.
I wonder if this info will help my case with WCC?
I wonder if this info will help my case with WCC?
Instructor
Joined: Aug 2001
Posts: 211
Likes: 0
From: Midland MI
Re: Cracked 5 spoke rim: Update (Gearhead Jim)
Jim,
Click on his link again, comes up as a bad page, BUT then you backspace the last "period" out of the URL and hit enter.... then it comes up fine.
Click on his link again, comes up as a bad page, BUT then you backspace the last "period" out of the URL and hit enter.... then it comes up fine.
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Burning Brakes
Joined: Mar 2000
Posts: 1,195
Likes: 0
From: Foothill Ranch, Ca Ca.
Re: Cracked 5 spoke rim: Update (BlackOps)
Had you killed your self at the track because of the broken spokes, Westcoast Corvettes would say, "Sorry, nothing we can do to compensate for his death, he was racing." "He did however broke the coffee mug he bought from us, so, we'll replace it at cost." "Coffee mugs are waranteed from WCC, even when racing. :lol: :lol:
:rolleyes:
Good thing you caught it!
:rolleyes:
Good thing you caught it!
Le Mans Master
Joined: Jan 2001
Posts: 6,450
Likes: 371
From: Maryville TN
St. Jude Donor '06-13,'16-'17, '19
Re: Cracked 5 spoke rim: Update (BlackOps)
Most profesional racing bodies have banned chromed wheels and suspension parts . It looks like you just found out why!
I hope you get this resolved. Good luck.
Tom
I hope you get this resolved. Good luck.
Tom
Thread Starter
Melting Slicks
Joined: May 2001
Posts: 2,186
Likes: 7
From: Evansville, IN The GOCC, rebels without a clue.
St. Jude Donor '06
Re: Cracked 5 spoke rim: Update (TCW)
Thanks, Tom.
No resolution yet. I'm waiting on the owner of WCC to return to work so I can appeal. Seems he's the only one with the authority to overide their warranty exchange clerk.
I got the set of polished rims installed in time for Willow Springs. It was a lot of fun. I hope those 110 mph runs through turn 8 don't break my new rims. :crazy: Pardon me, while I go change my underwear.
No resolution yet. I'm waiting on the owner of WCC to return to work so I can appeal. Seems he's the only one with the authority to overide their warranty exchange clerk.
I got the set of polished rims installed in time for Willow Springs. It was a lot of fun. I hope those 110 mph runs through turn 8 don't break my new rims. :crazy: Pardon me, while I go change my underwear.
Instructor
Joined: Sep 2000
Posts: 155
Likes: 0
From: Chatsworth, Ca. 91311
Re: Cracked 5 spoke rim: Update (vetterdstr)
I just ordered HRE 541's 20x10.5 and 19x9.5 from Shawn at The LAPD. I hope these don't crack too. My factory wheels are out of warranty with 38,000 on the clock. I think the bottom line is that any wheel can crack. I was just one of the unlucky ones with either an air bubble in the aluminum or some other type of defect. Life goes on.
