So this last weekend I decided that light weight wheels are going to be my next big purchase for my car. (997 WB) I have looked extensively at several options, from several brands including dymag, HRE, and AMT. I am fearful b/c a friend was at an event and saw a CF wheel fail and he sent me pics when I mentioned I might be buying the dymags.

My questions are,

1. has anyone else experienced this type of failure? If so what were the circumstances under which it happened? (track, street, ???)

2. What could cause a wheel as expensive as these are to fail so catastrophicly? I really want lightweight wheels but not at risk to myself or others.

3. Is there any independent testing of aftermarket wheels that the different manufacturers use that I should familiarize myself with before my purchase? Maybe I assume incorrectly that there is some sort of testing/quality control to ensure these failures don't occur.

 

How exactly did that happen?? On the race track?

 

ouch! that looks nasty.

Also check out Champions, not as light as dymags but stronger & also lighter than HRE's.

 

Those 171s are my new favorite wheel. I would never use dynamags.

 

That wheel was obviously destroyed through track usage, look at the hoosiers that they are wrapped in.

Personally I'm not entirely sold on carbon-fiber wheels, because the entire thing isn't carbon fiber so I question how the carbon and non carbon pieces are attached.

I got the RS171s very light, very strong, visually appealing, and no worries about leaks or anything else.

Plus if you are looking to save weight RS171s will run you $5K less than the dymags and you can certainly use that to make some more light weight purchases.

 

Wow can you say failed badly. The center on these wheels is magnesium? The Carbon Fiber looks like it held up.

 

wallmon-"How exactly did that happen?? On the race track"

Yes, I know it was on track, but apparently it didn't suffer any impact prior to disintegrating mid-turn. I plan on using my new wheels for the track as well, hence all the questions.


RTEAMSTRADALE- "Also check out Champions"

Thank's I will look into them, The Dynamags (or any CF+alloy wheel) have dropped to the bottom of my list for obvious reasons. since it think the new HRE's would look great with black centers.

raiyu-"I got the RS171s very light, very strong, visually appealing, and no worries about leaks or anything else."

I am looking into those as well (they look good), Glad to hear that you like them. Do you have slicks or street tires on them, because whatever I get is getting R-compounds from the start.

M3 S3-R- "The Carbon Fiber looks like it held up. "

Yeah when the guy told me he had pics of a failed one I totally expected it to be the CF lip having hit a curb or something, but it appears the Magnesium fatigued and failed under track use.

 

Its my daily driver and track car, I'm running Michelin Pilot Sport Cups on there, couldnt be happier with the tires and the rims.

 

Looking closely at the pictures, the spokes appear to have be attached to the CF barrels with some sort of adhesive. Am I just seeing things?? I'm wondering what failed first.

 

This appears to be a fatigue failure caused by high cornering loads. The bolts are still attached to the spoke ends. Magnesium is not very forgiving about this.
This problem probably should have been detected in a cornering fatigue test by a third party lab.

 

Wow. What happened to the rest of the car after such an apparently massive failure?

 

I'm really surprised to see the that the centers were held to the barrels by adhesive alone. I thought the carbon was laid around the base of the spokes, not under it.

Dymag is sure a pioneer, they'll get there....

 

Damon,
There is a bolt at the end of each spoke that attaches the center to the CF hoop. Looks like the CF held up pretty well in spite of the center failure.

 

To those of you suggesting the spokes are held on by adhesive alone, did the thought ever cross your mind that the adhesive would have to be stronger than the breaking point of 9 1" square magnesium spokes?
Also, if it were held on by adhesive, the whole center would separate from the barrel, not break like it did.
Finally, if it were held on by adhesive only, the spoke ends wouldn't be hanging on the wheels as seen in the pictures.

Let's use some common sense guys. It's an impossibility to glue a wheel together. There is obviously a series of bolts holding the center to the barrel- just as in every other mutli-piece wheel. It's apparent that one bolt holds each spoke on, as each spoke has had enough force to break free the adhesive (yes, it's there, but it has no true structural value- it's likely to seal the bolt holes or something of the sort) and has "swiveled" on their bolts.

I may be wrong here, but I'll put my money where my mouth is. '

In any case, I would assume that this is easily avoidable with proper engineering and testing. It just doesn't look to me that Dymag wheels are ready for the big league.

 

I have over 10 K miles on my Dymag's and I have had no problems with them
The are certified to TUV standards....

GEE-BEE

IAM MORE AFRAID OF THE SOFT SIDEWALLS ON THE MICHELIN PS2"S