: those with powdercoated wheels beware.



lilgCTS-V
08-15-11, 01:28 PM
I ignored the warning. Supposedly when you powder coat a rim due to the heat process it goes threw it will weaken the rim. I hit a pot-hole about 4 months ago and it dented my passenger front and rear rim and now i noticed a crack in one of the spokes and little cracks on two others... so pretty much this is just a warning to make sure A. your powder-coater is very experienced with car rims and B. think about just spray painting.

thebigjimsho
08-15-11, 06:27 PM
Yep, good advice.

cvettr/cts-v
08-15-11, 06:41 PM
yeah I thought about powder coating awhile back untill people started having the same issue you mentioned so staying stock for me.

hXc95SLS
08-16-11, 08:27 AM
I just painted mine the same color code as the car. Sand blast, spray and a metric ton of clear.

lucasmartin
08-16-11, 09:45 AM
Great info. I bought the car used and the rims were powder coated already. I'll keep an eye out. Thank you

DrSpeed
08-16-11, 11:25 AM
In order to provide a sound metallurgical opinion on this, one would need to know the casting alloy and heat treat condition (i.e. T6 or whatever). Many common casting alloys, such as 356, are aged at 325F . If exposed to a powder coat cure schedule of 375-400F for 10 minutes or so, some over-aging *could* occur and the fatigue life of the wheel could be reduced. It all depends. New coating materials can be baked at 250*, so that would be a safer bet.

To nerd it out, here are some T6 specs....

DrSpeed
08-16-11, 11:26 AM
ASM Handbook Volume 2, Properties and Selection: Nonferrous Alloys and Special-Purpose Materials has the following information:356-T6: aging at 305 to 315 F for 2 to 5 hoursYield stress = 185 MPaUltimate stress = 262 MPaFracture strain = 0.05356-T7: aging at 435 to 445 F for 7 to 9 hoursYield stress = 165 MPaUltimate stress = 220 MPaFracture strain = 0.06Based on these data, a 400 F treatment for less than 1 hour shouldn't reduce the fatigue strength significantly.

lilgCTS-V
08-16-11, 06:10 PM
i got em done about 2 years ago so im not devistated, plus its an excuse to buy some new rims either siler team dynamics or the wheels that rander got depending on how they look.

EdmundGTP
08-17-11, 01:29 PM
That's assuming the wheels are even aged to a T-6 condition.. And that they're even 6061 to begin with.


I've seen plenty of wheels that WEREN'T powdercoated suffer similar damage from pot-hole hits.

JNR
08-21-11, 06:20 PM
Aren't the oem wheels cast aluminum, as well?

I don't know how the wheels would do with them being powdercoated and IMO depends on the cooling method, also (as far as altering its composition)...I would think a few hundred degrees wouldn't do a whole lot. I mean, if we were talking 800 that may be a different story, but countless wheels are and have been powdercoated and doesn't seem to be a whole lot of failures...or maybe there are...just doesn't seem like there would be.

Also, chrome plating would seem more detrimental than powdercoating, but again you rarely hear anything of failures from that, either...

liqidvenom
09-04-11, 12:46 PM
i don think this was due to the powder coating but more of you hitting a pothole hard enough to dent the wheel and keep on using it.

67electro
09-06-11, 05:44 PM
yeah, CTSV wheels are KNOWN for being fragile.

cracking would take extreme temps and then UN even cooling, if it didn't crack on the cool down, It shouldn't make it weak for a future day to decide to crack.

(IMO)

lilgCTS-V
09-07-11, 02:00 PM
well hopefully buying the road hazard protection will pay off and they will give me new rims, i really hope the powder-coating doesn't void the coverage.

Twitch
09-07-11, 03:48 PM
I actually powdercoated my rims a second time this past winter with no problems yet. And I would think driving in NYC is as good a test as any.

We'll see...

AAIIIC
09-07-11, 07:26 PM
yeah, CTSV wheels are KNOWN for being fragile.
They are? Known where? Because it doesn't appear to be known here.

catch2otwo
09-08-11, 09:56 PM
yeah, CTSV wheels are KNOWN for being fragile.

(IMO)

Thats the dumbest thing I think I've heard in a long long time... are we sure the wheels are not an alloy of egg shells and bubble gum?

atdeneve
09-11-11, 04:29 AM
Aren't the oem wheels cast aluminum, as well?

Stock wheels are not cast, they are forged.

lilgCTS-V
09-11-11, 09:34 PM
isnt forged supposed to be really strong ?

catch2otwo
09-12-11, 12:16 AM
Every material out there has a yield point. You hit something hard enough it will deform it. Even forged wheels

thebigjimsho
09-12-11, 10:57 PM
Stock wheels are not cast, they are forged.I've always known them to be cast wheels...

54inches
10-09-11, 08:02 PM
Some powdercoaters do not or will not bake above 350 or so degrees because the heat anneals the metal to a heat range that realigns the crystal and make them weaker.

As long as the powdercoater keeps the process at a relatively low heat and uses the proper lower heat powder, the wheels will not be affected at all.