John's 991

I wanted to let you all know that I found a small crack on the inside of one of the spokes on the right front wheel on my 2012 991 with Carrera S wheels. I have not hit any big pot holes or curbs that would explain the crack, and I am taking it to the dealer next week.

If any of you are tracking your 991, you may want to double check them just in case. Hopefully this is atypical.

I also posted this in the 991 Forum, but wanted to make sure the track oriented folks where included.

Hella-Buggin'

Thanks for the heads up.

John's 991

Here is a pic for those who are interested:

John's 991

Question for all you mechanics and amateur metallurgists out there:

Somebody brought up that it looks like the spoke was hit by a pry bar or similar causing the straight line mark in the wheel at the top of the spoke. This weakened the wheel leading the the curved crack. Does this seem plausible?

The crack was not caused by hitting a curb or pothole to the best of my knowledge.

amso3

John, are you sure it is a crack. I don't mean to be smart, but, unless it is an big crack, it should be liquid penetrant tested to be sure. Your photo is not convincing to me. A crack here should be going across the web, not out toward the wheel.

To answer your question, a sharp scratch can initiate a crack, but my opinion is that this wheel should have a large factor of safety in it's design from Porsche. A scratch should not initiate a crack in that type of situation. FYI, I'm a licensed PE with a Masters in Mechanical Engineering, but I'd rather make a comment after seeing the wheel in person.

J richard

Not sure on the 991 but I had a similar gouge from a stone getting caught between the caliper and the spoke. Not a lot of room and a trip through the gravel gets it everywhere...

John's 991

Amso and J Richard, It would be great if it was just a scratch and not a crack. It has "depth" to it, so it is at least a pretty good scratch. As I track the car, I want to be 100% sure it is safe, as you can imagine. A wheel failure cannot be an enjoyable experience.

I'm taking it to the dealer next week and I will report back. Thanks for the input guys!

ny991

Any imperfection with depth to it is a serious concern, good catch. This reminds me to look the wheels over a bit better before a track day, thanks!

John's 991

NY 991, That was the main reason for me posting this here. I wanted to make sure all the folks with 991's check just in case. I am still leaning towards the spoke getting scored when the weight was removed and a crack formed from there. It would be a happy ending if it was just a scratch, but better safe than sorry.

Have fun at your event .It is sunny and warm here in CA, not sure the same in NY.

Gofishracing

is that built up dirt on the surface of the wheel? Such a clean wheel- it seems strange.

Van

I think that black goo is where a wheel weight was pried off when, perhaps, the wheel was rebalanced.

The nick the OP mentions might be from a screw driver used to pry the weights off?

Frank 993 C4S

Agreed.

Without some appropriate testing, there is no way to tell whether this is a surface scratch or crack. My bet is that it's just a scratch.

Gofishracing

that would be ALOT of wheel weights. Yes- maybe "tech" slipped with screw driver- I'd change shops

John's 991

UPDATE FROM THE DEALER: The dealer declares that it is a scratch and not a problem. I will put some paint on it and keep an eye just in case. Thanks to all of your for your thoughts and input along the way. I will be keeping an eye on the wheels just in case.