See my first post...scarry stuff. I wouldn't trust these wheels again. TWO were cracked on my car and you can see others that I put up as well..so this isn't an *isolated* fluke.

 

That's the problem...

High quality cast and forged wheels come with the best balance of tensile strength and fatigue performance from the factory. Most cast wheels are 356 T6 alloy and aged at 300-315F, most powders are baked at 350-400F. If it's a two stage base/clear powder, it goes into the oven twice. Factor in uncontrolled cooling temps/times and the structural integrity is compromised.

OEM processes, quality control, R&D far exceed some guy throwing wheels into an oven. Smaller companies are more concerned with production turn around time, aesthetics, and less about structural integrity, combine that with China made blanks and you've got quality issues.

 

I was really referring to forged wheels, and post purchase powdercoating (relating to the comments, if you get a forged wheel don't powdercoat it).

I understand what you are saying, but it usually takes hours for metal fatigue to change in those alloys, and its pretty insignificant. I'm sure it CAN be harmful and in some cases is, but generally it is pretty safe. Especially with a reputable shop.

 

while doing a search on Forgestar F14's i came across this thread... Mr. Sparco, you may be onto something here?!

also, the fact that these are cast and most of the wheels support is at the spokes is another reason i believe these are cracking only at the inner edge.
it's similar to an aluminum soda can, easy to crush in the middle...

what could also be happening, theory, (merc owners situation), the rim shop is grabbing the inside of the rim with the tire machine. it's the start to the end, creating the stress points, overtime the stress points develop into full blow cracks.

this kinda sucks, lol, because i really like the Forgestar lineup for the price.

 

Thanks for sharing op. Been eyeing a set for my GS300 DD'r. Not anymore with the family in mind!

 

Side note:
The guys on this site always find a way to crack wheels. Not sure if it is the actual weight of the car of what but if ya want to know if a wheel will hold up just check MY350.COM!

I bent my old Volks.. keyword bent! Still held air and no wobbles

 

Yeah but like 70% of the time its because they were doing dumb shiit, and this is a case of the other 30%.

Good writeup OP, thanks for sharing to prevent other Z owners from making the same mistake.

 

Ouch, stick with real racing brands? Volk/Ray, Work, Enkei, BBS etc?

 

I'm sure other wheels like Konig or TSW would be fine. These particular wheels are specially spun cast (NOT FORGED!) to be much lighter (and they are light) because they are *supposed* to be STRONGER as well. That's the problem! Apparently the quality control is lacking so many are DEFECTIVE and can't take the stress. The barrels are made in China and then sent here for machining and finishing.

 

Glad my Forgestars are still going strong

 

Good for you..if you get tire pressure warning watch out.
If you don't have TPMS...check pressures often.

 

Dam was about to order a set of super concave... should i just get vertini magic instead?