Oops...broken RPF-1 :-(

[scby rex]

Originally Posted by Turn in Concepts

Agreed! I have told so many people this and most of them look at me like I have two heads.

Tony

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[Scooby921]

Originally Posted by Web Foot STi

One notch was catastrophic?

Not in the world that we know.

Other than satiates who designs that close to the edge? (SST went down with a cascade failure.)

(I've been around some campaigns. No fun.)

I don't think one chip could have been catastrophic. I think one chip could have started the whole thing and the last xxxxx number of times I'd autocrossed and/or driving this week just helped that one chip turn into a crack and do what it did. It doesn't take a whole lot for a small crack to turn into a huge break in an aluminum casting. You crack it and the next load cycle can snap it.

Originally Posted by draco159

Wow thats crazy! Sorry to get off topic, but OP do you happen to have a pic of the wheels on the car? They look great!

No recent pics with them on the car. I'm kinda bummed that I didn't take any.

Originally Posted by Uncle Scotty

wheels are wear items....the fail just like all other man made mechanical objects

The sad, unfortunate truth

[draco159]

Scooby, what color did you paint them? I like the wheels, but for some reason the factory silver color they come with makes them appear smaller. I like the gunmetal color you chose though. Any updates form Enkei or your supplier?

[Scooby921]

Originally Posted by draco159

Scooby, what color did you paint them? I like the wheels, but for some reason the factory silver color they come with makes them appear smaller. I like the gunmetal color you chose though. Any updates form Enkei or your supplier?

No updates yet.

These wheels were painted Subaru's factory bronze that they use on the Leggy and Tribeca. I just had the shop put in more black to darken them up. They used 35% more black. Turned out fantastic IMO. They look almost black at night, but shine a bright bronze in the sunlight. If you're looking to have some wheels painted the same color I have the paint can/mixture percentages if you use a shop that has the PPG paint system.

Perhaps when we get another sunny day up here in MI I can snap some pics of them out in the sun.

[draco159]

Originally Posted by Scooby921

No updates yet.

These wheels were painted Subaru's factory bronze that they use on the Leggy and Tribeca. I just had the shop put in more black to darken them up. They used 35% more black. Turned out fantastic IMO. They look almost black at night, but shine a bright bronze in the sunlight. If you're looking to have some wheels painted the same color I have the paint can/mixture percentages if you use a shop that has the PPG paint system.

Perhaps when we get another sunny day up here in MI I can snap some pics of them out in the sun.

Wow, I never would have guessed that they were bronze! So the shop you had paint them, did they just dip the entire wheel in a paint stripper solution? That sounds so much easier than hand sanding. If you don't mind, how much did that run you to have them do that? You can pm me the quote if you want. I was leaning more towards the Rota gunmetal color to go with my cgm wagon.

[Scooby921]

Originally Posted by draco159

Wow, I never would have guessed that they were bronze! So the shop you had paint them, did they just dip the entire wheel in a paint stripper solution? That sounds so much easier than hand sanding. If you don't mind, how much did that run you to have them do that? You can pm me the quote if you want. I was leaning more towards the Rota gunmetal color to go with my cgm wagon.

I had the wheels chemically stripped by a local shop that does paint stripping. I took the bare wheels to the body shop and they did final prep, primer, paint, and clear. Cost me $120 to have them stripped and $100 to have them painted. Helps that the body shop is owned by a friend's family and he happens to work there.


Gunmetal looks good on CGM. So did this bronze. I had both on my CGM WRX .

Some candy for you since you're thinking gunmetal...rota torques


These were my old winters in a rattle can bronze, the RPF-1s are a bit darker

[draco159]

Thanks! You actually posted that first pic and last pic in my thread about which color wheels for a cgm WRX . I like the gunmetal color b/c it's dark but just light enough to stand out from the tires, so I think I've ended up choosing the 17x9 DPT's in gunmetallic. But now that I see I could get the RPF1's in a similar color I think they're back on the list.

[Scooby921]

Update:

Got a call from Enkei last night. At current they aren't going to warranty the wheels. Having them painted apparently voided something. The customer service guy doesn't understand why, but that's what he was told. Being superb customer service he wants me to send the cracked wheel in so he can have it looked at and analyzed. He's going to keep pushing to have them warrantied. for Enkei's customer service!

[jigga]

wow.. scary stuff... Had a similar thing happen to the stock 17 inch aluminium wheels on my previous car.

And I am considering picking up some RC T4 wheels, but am afraid that since they are in a size that Enkei USA does not bring in, they might leave one in the cold..

[Scooby921]

Update #2...

I got the tire dismounted from the wheel yesterday to box it up and ship it to Enkei. When I looked at the wheel again I noticed dark lines across the back side of the majority of the spokes. When I run a fingernail over the spokes I can catch a couple of the "lines"...more cracks. Now I'm really glad I caught the crack and stopped driving

Pics coming when I can get them uploaded to the interweb.

[gpshumway]

Originally Posted by Scooby921

They were painted...PPG automotive paint. Prior to painting they were dipped in an aircraft grade chemical stripper, no blasting and no high-temp baking involved.

It's possible that chemical stripper caused hydrogen embrittlement. Acid baths can cause the problem. Were the wheels baked after the stripping process to allow the hydrogen to diffuse out of the material harmlessly?

Mind you I have no idea the particulars of your stripping process.

Wikipedia entry on Hydrogen Embrittlement

[littlewhitewagon]

The Enkei US guys are very nice and will work with you resolve whatever they can. Unforunately, they do have to abide by the rules and by altering the finish of the wheel, you voided the warranty because they have no way to know if the work was done right or not. This was one of my worries when I powdercoated my Enkei ES-Tarmacs because I didn't want white wheels on a white car.

It's good that you can accept that wheels are a wear item like tires and it's even better that you inspected it. At least RPF-1s are still available and not very expensive.

[Web Foot STi]

Originally Posted by gpshumway

It's possible that chemical stripper caused hydrogen embrittlement. Acid baths can cause the problem. Were the wheels baked after the stripping process to allow the hydrogen to diffuse out of the material harmlessly?

Mind you I have no idea the particulars of your stripping process.

Wikipedia entry on Hydrogen Embrittlement

If you read your link you will see that aluminum isn't very susceptible to hydrogen embitterment. It's more of a problem with steel. One of the worst examples is chrome plating and not properly baking the H out afterwards. That's why there is no such thing according to the SCCA as a chrome roll bar. They don't want to get involved with processing.

These wheels were not baked. That is a heat treat/artificial age issue. They were striped with and aircraft chemical stripper. One that the FAA is ok with using on Al. They are kinda picky about such things.

Those black lines on the other spokes is the typical wear debris that works its way out of a tight crack fretting and propagating. In the past I did a lot of fatigue testing of cast A356-T6 Al truck hubs and saw a lot of those black lines. Typically the initial one would be so tight that wet florescent dye penitent would not indicate, but wipe the black off and run for another hour, or so and the black line would be back. Sooner, or later that crack would take off, trip the limits, and you would have a box of broken parts. It's impressive when a hub disassembles itself at 1,200 rpm under 13,200 lb vertical and 6,600 lateral load...

Glad that wheel the had enough belt and suspenders so that the whole spider didn't tear out at once.

Looking at the photos again from the back you can see the relatively sharp corner where the parting line was ground. Perhaps this is where things started? I know inside radii get all the attention, but outside corners can cause problems too.

[gpshumway]

Originally Posted by Web Foot STi

If you read your link you will see that aluminum isn't very susceptible to hydrogen embitterment. It's more of a problem with steel.

Its much more common with high strength steel, but it's not unheard of with Aluminum. The fact that these wheels had been chemically stripped raises the question.

Originally Posted by Web Foot STi

These wheels were not baked. That is a heat treat/artificial age issue. They were striped with and aircraft chemical stripper. One that the FAA is ok with using on Al. They are kinda picky about such things.

It's certainly possible that the FAA approved procedure requires a post-treatment for certain alloys which was not performed in this case. Its been a while since I specified a process which required post treatment on aluminum, but my recollection is a long duration, low temperature bake was recommended for alloys subject to issues with certain plating processes.

Again, I have no idea what alloy the wheels are made from or what potential issues the stripper and its related process pose, I'm simply suggesting the possibility that the stripping process weakened the wheel. Given many auto-x and open track guys run these wheels without issues, I wouldn't write off the possibility.

Of course it's unlikely Scooby921 will be paying someone to autopsy his wheels, so we may never know for sure.

[Scooby921]

Pics...red paint marks outline what I feel are additional cracks. As mentioned yesterday, I can catch my fingernail on a couple of them.

[ritky]

Wow, you better go check your other wheels!!!

[Web Foot STi]

Interesting pics. I can now see why the cracks didn't start by the hub and did in the middle of the spokes.

My OEM wheels have the same sharp corner on the back of the spokes, but they do not have the grind marks I can see in the photos. I went and looked. (I'm not a fan of forgings over castings in fatigue however.)

[STi-MAN]

i guess guys at the evo forums know that the rpf-1s are more prone to cracking then the nt03's. good luck with your wheels

[k-dogg]

Any Updates?

[Scooby921]

Been awhile since I've gotten a response from Enkei. After a couple emails and voicemails they responded.

Warranty dept said no warranty coverage because they've been painted. The person I was working with, whom I believe is a sales rep and not a customer service person, said he'd sell me a new set for a discount since they shouldn't have cracked. I'm happy with that. I kinda figured I'd be SOL.

But first he wants me to send the cracked wheel in to be analyzed. Perhaps they'll find a casting flaw and it will get covered. Can't hurt me since the warranty guys already looked at pics and said no. Perhaps the physical specimen will change things. UPS picked it up yesterday and I'm not sure how long it'll take.

[jutes85]

Nice!

You just find the number off their main website?

[gpshumway]

Originally Posted by Scooby921

Been awhile since I've gotten a response from Enkei. After a couple emails and voicemails they responded.

Warranty dept said no warranty coverage because they've been painted. The person I was working with, whom I believe is a sales rep and not a customer service person, said he'd sell me a new set for a discount since they shouldn't have cracked. I'm happy with that. I kinda figured I'd be SOL.

But first he wants me to send the cracked wheel in to be analyzed. Perhaps they'll find a casting flaw and it will get covered. Can't hurt me since the warranty guys already looked at pics and said no. Perhaps the physical specimen will change things. UPS picked it up yesterday and I'm not sure how long it'll take.

Wow, good news. I wonder if they'll share any of their autopsy findings with you.

[ButtDyno]

Did you ever hear back from them about this?

<- glad he never painted his Tarmacs since they don't make em anymore

[slowguy]

Hate to bring this thread back from the dead but looking at where the cracks are on the back of the wheel, it looks very even throughout each spoke. Could these deep scratches/cracks have been caused by your calipers?? Reason for this inquiry is because I ran 17x9.5+38 (with a 5mm spacer, effective +33 front offset) on my STI and caliper clearance was MINIMAL at best (two, three sheets of paper clearance) and I have noticed some visible scratches from the caliper on it.

And any word from Enkei?

[littlewhitewagon]

Originally Posted by ButtDyno

Did you ever hear back from them about this?

<- glad he never painted his Tarmacs since they don't make em anymore

<--- stupid guy for powdercoating his Tarmacs... but they are all bent to hell now. These things were not as strong as I thought they should be. Berms from the tracks, potholes and jumping things... ugh.