: Broken spoke on powdercoated accessory wheels



pveomett
04-15-10, 03:11 PM
Well, I guess the title pretty much says it all... I noticed Monday when I was washing my V, that the front drivers side wheel has a crack all the way around one of the spokes. At first I was hoping it was just the powdercoating that was cracked, but it's through the spoke. I know that it happened in the last week, because I washed my car the week prior; and I would have noticed that if it was there before. I don't have any pictures right now, but I can get one later.

I didn't notice it driving different before I saw it. Since I saw the crack, there seemed to be a SLIGHT shimmy in the front end. I'm aware that it's probably just all those placibo's that I took, but I would feel like a real ass if there was an accident caused by driving a car that I knew might not be safe... So I have started driving my Jeep again, untill I get this resolved.

I don't know how this could have happened, it could have been from hitting a pot hole, or one of the other enormous defects in the NY State Thru-way... I find that kind of hard to believe though. I searched the forum, and there was another guy with the regular (non accessory) wheels that had cracked like 3 or 4 of the spokes on his wheel. His where also powdercoated, but I can't imagine that having anything to do with this... Maybe, who knows?

Now I need a place to get a decent deal on another GM accessory wheel... It won't matter if the finish looks like crap, or if there is some curb rash, because I will have to sandblast and powdercoat the new wheel. Anybody have any leads? I'd rather not buy new if I don't have too.

I'm thinking the broken wheel should be safe enough to use as a spare tire (since I already don't have one). It sucks, but I can't really complain too much because my V has been relatively trouble free. And since I don't know how this happened, there really isn't anyone to blame...:want:

814V
04-15-10, 03:18 PM
I would say its probably a flaw in material. Depending on your powdercoater you can damage the wheels and make them weak if you heat them up to much. You would have to smack something pretty hard to crack a wheel. I have seen them bend but never crack. Good luck to you!

BLACK CAR
04-15-10, 11:30 PM
I have a stock wheel not powder coated that broke. No bends or blemishes on the tire either. The dealer wouldn't help out or give an explanation either.

BLACK CAR
04-15-10, 11:35 PM
picture

http://i706.photobucket.com/albums/ww63/ctsvdaddy/IMG_0756_1.jpg

http://i706.photobucket.com/albums/ww63/ctsvdaddy/IMG_0755_1.jpg

deedubb
04-16-10, 12:38 AM
Woah, thats crazy!

Nasty93
04-16-10, 11:30 AM
WoW, never seen anything like it

AAIIIC
04-16-10, 11:30 AM
His where also powdercoated, but I can't imagine that having anything to do with this... Maybe, who knows?
Yes, powdercoating forged wheels can lead to exactly this sort of thing. BBS North America specifically advises people not to powdercoat the factory forged aluminum STI wheels due the possible compromising of the material's strength and ductility.

Most alloy wheels are 6061-T6. The heat treatment to get 6061 to T6 is to hold it at 350F for 8hrs. Now you're heating that already heat treated alloy at the same or higher temperature when you powdercoat the wheel. Admittedly, you're doing it for a much shorter period of time - 15-20min is what I've seen for powdercoated parts - but any heat treatment after you've taken that 6061 to T6 is going to weaken the alloy.


Now I need a place to get a decent deal on another GM accessory wheel... It won't matter if the finish looks like crap, or if there is some curb rash, because I will have to sandblast and powdercoat the new wheel.
If I were you I'd be looking at painting the new wheel to match the others, and I'd be watching the others like a hawk for cracks to appear.

thebigjimsho
04-16-10, 01:00 PM
Yes, powdercoating forged wheels can lead to exactly this sort of thing. BBS North America specifically advises people not to powdercoat the factory forged aluminum STI wheels due the possible compromising of the material's strength and ductility.

Most alloy wheels are 6061-T6. The heat treatment to get 6061 to T6 is to hold it at 350F for 8hrs. Now you're heating that already heat treated alloy at the same or higher temperature when you powdercoat the wheel. Admittedly, you're doing it for a much shorter period of time - 15-20min is what I've seen for powdercoated parts - but any heat treatment after you've taken that 6061 to T6 is going to weaken the alloy.


If I were you I'd be looking at painting the new wheel to match the others, and I'd be watching the others like a hawk for cracks to appear.
Yep, what Pat said...

supergeess
04-16-10, 02:26 PM
Whose wheel is in the above pic? That doesn't look like an accessory wheel.

The guy who stretches my wheels has always recommened against powdercoating for this reason.

Since BLACKCAR had the same issue wih a non powder caoted wheel, it seems that the wheel's integrity was flawed.

AAIIIC
04-16-10, 03:52 PM
Whose wheel is in the above pic? That doesn't look like an accessory wheel.
You're right, that would appear to be a stock wheel, not a GM Accessory wheel.

pveomett
04-16-10, 04:20 PM
That was his wheel not mine, and it appears to be the stock finish (not powdercoated)... I have a picture of mine on my phone, I just need to wait untill I leave work to upload it. Not much to see, it looks just like the picture above (except on a different wheel).

Having the wheel painted instead of powdercoated is definately something I will have to think about. I'll have to see how close they can match the color/finish with paint. For a brief moment I was thinking (insert joke here); what are the odds of this happening to a second wheel on my car, considering how many people have powdercoated their wheels and how many have had failures like this... Then I remembered what kind of luck I can have sometimes... The odds are pretty good that if I powdercoat again, the new wheel will also crack (I have it like that...).

It is interesting that if the heat from the powdercoating process caused my issue, than why did BLACK CAR's wheel have the same problem? And why aren't more people with powdercoated wheels having this problem? Oh well, I guess neither of those are questions that can be answered...

Thanks for the input guys.

BLACK CAR
04-17-10, 11:26 AM
YES,

That was a stock wheel with stock finish. I did not hit any pot holes and there was no bending or scratches anywhere on the wheel. The tire was also in perfect shape.

I thought the stock wheels are powder coated???

RGRATTAN
04-26-10, 02:34 PM
I have the same issue now twice has any anyone heard any other news on this issue?

Junior1
05-04-10, 01:00 AM
Any updates on this?
I was looking to have my stock wheels powder coated this week, now thinking twice...

c4ss
05-04-10, 01:29 AM
I don't know how I missed this thread either the first time around. Did you ever get that fixed man? I've never seen anything like that either. Hoping you do before the next V-day. Last time was a blast :thumbsup:

ELES6CTS
05-04-10, 02:07 AM
Here's a pretty good thread regarding powdercoating. http://www.eng-tips.com/viewthread.cfm?qid=151053

Junior1
05-04-10, 07:32 PM
Talk about pissing on my parade :rant2:

ELES6CTS
05-04-10, 09:11 PM
Talk about pissing on my parade :rant2:

I think it depends on what kind of curing process your powder coater takes. It can still be safe as long as the heat does not exceed a certain point.

Junior1
05-04-10, 10:50 PM
I think it depends on what kind of curing process your powder coater takes. It can still be safe as long as the heat does not exceed a certain point.

Gonna call and see what they say, found a few places to paint em just in case too

RADARB8
05-05-10, 07:47 PM
YES,

That was a stock wheel with stock finish. I did not hit any pot holes and there was no bending or scratches anywhere on the wheel. The tire was also in perfect shape.

I thought the stock wheels are powder coated???

Yes, the stock alum silver wheels are factory powdercoated.

AAIIIC
05-05-10, 11:40 PM
Gonna call and see what they say ...
I personally wouldn't trust the material science pedigree of a guy at a powdercoating shop.


Yes, the stock alum silver wheels are factory powdercoated.
I don't know what the split is of powdercoated vs. painted, but both techniques are used in the aftermarket and for OEMs. The important difference for OEM powdercoated wheels is that the PC process is accounted for in the manufacturing process. In other words, they don't do the PC after they've done the final heat treat of the alloy wheels; instead, they do it as part of the heat treat.

Junior1
05-06-10, 04:10 PM
I personally wouldn't trust the material science pedigree of a guy at a powdercoating shop.

I'm just calling to see what process they are using, the temperature of that process and the duration of it.

tweeter81
05-07-10, 12:01 AM
Another thing. I wouldn't be so quick to blame the broken spoke on powdercoating. The accessory wheel has some of the narrowest spokes I have seen on a wheel, (short of the really high quality, high dollar custom jobs).

It could just be that the wheel casting had an imperfection and the narrow spoke just couldn't hold up to the abuse.