sandblasted 6UL Failure - need replacements
 

I noticed yesterday that the two first-gen 6ULs I had sandblasted and painted a couple years ago are failing. One has a broken spoke, and both have a few small cracks forming all over the place. The two I didn't sandblast look fine.

So, if this happened to you, what would you do?

-Hunt for 2 1st-gen 6ULs
-2 new 6ULs
-4 new 6ULs
-4 new wheels of some other variety, if so, which wheels?

I have been really happy with the 6ULs except for the finish, which starting chipping a year or so after I got them. That's why I sandblasted them (don't sandblast your 6ULs, it appears to cause failure).

I'll probably stick with 8" width, since I only ever put street tires on the car and autocross, but if I don't have to do any rolling and it's not much more money I could probably be convinced to to go 9"

Sorry if this info is all out there, I haven't been paying much attention to the wheel selection since I bought my 6ULs 5 years ago.

1gen 6UL seems to need constant monitoring for cracks. Mine have not shown any yet (I have not found any, no Xrays), but for racing friends around me the failure rate is quite high.
Later generations seems to be much better, but wheels are consumables in racing (however, some last much longer than others, and when you learn which one to have they are replaced by a new experimental version).

Make sure you send Emilio an e-mail about this. At the very least its probably good information for him and maybe he will be super nice and give you a discount on a new set!

The 1st gen 6ULs aren't as strong as the 2nd/3rd gen. Emilio posted/hinted about this on his website.

Yeah, these wheels are old enough and since I sandblasted them, I don't expect any sympathy from Emilio. I'll send him a note for his info, though.

So it sounds like we have two votes against 2 replacement first-gen 6ULs

Oh, these wheels have never seen a track, but they have done a bunch of autocrosses and probably 35k street miles.

I just emailed Emilio, and I'll try to post a picture or two here this afternoon showing the damage. It looks like 15x8s in Nickel are sold out everywhere, which is annoying because that's sort of the direction I'm leaning right now.

Sandblasting and sanding creates stress risers. You should never use these processes on metal pieces that are highly stressed.

Personally, I'd get new 6UL's. Seems they've served you well. Dunno' about the 9" fitment without rolling. Curious myself so sub'd.

Yeah, and I think I knew the risks of sandblasting when I did it, but somehow I had already committed before I realized them, so I went ahead with it anyway.

Wheels are wear items. :P

The NAs require a front and rear fender roll with x9s. If you have lowered the car, I would imagine you'd have to roll at least the fronts. It's a big wheel for such a small car. I love mine.

Four new 8" 6UL's. You can use your two good wheels as spares/backups.
:2cents:

What this guy said.

Unless you are in a hurry and can't find a set in the finish you like from 949, TSE, Goodwin, or Phil's. Then you can consider some other 15x8" options.

Sort of related, sorry for thread jacking.

Is there a guide for identifying Gen1 vs Gen2 vs Gen3. I know about the above mentioned "6ul" cast into the face. Do the center cap designs also designate the different generations? Hex caps vs flatter bubble caps, vs ______?

Center caps are not attached to the wheels, I wouldn't trust that to identify the wheels.

Otherwise, I don't know how to identify Gen3 wheels.

"949 Racing" is smaller test than Gen 2. Gen 3 text is roughly 12pt and looks italicized, Gen 2 is ~18pt and block lettering.

Ok, so I want 15x8 6ULs in Nickel. They appear to be sold out everywhere, can anybody prove me wrong? I have an autocross in a week and a half I'd like to attend, but not on broken wheels!

Get black then, this is what I did for my wet tires when Nickel we're BO

It's like you have never been to 949's website :giggle:

Wheel Tech - 949Racing.com

TL;DR

• Gen1: Does not have "6UL" cast in the face, 59.1 or 54.1mm hub bore
• Gen2: Has "6UL" cast in the face, 67.1mm hub bore
• Gen3: Looks like Gen2 but has "VIA" stamp near the valve hole, 67.1mm hub bore

I'll go snap a pic of the VIA stamp tonight if that's worth anything to you.

You checked with all four of the vendors I listed above?

Yes, all four of those places seem to be out of nickel 15x8s. I caved and bought silver 5 years ago because of this, and I don't want to do it again. I've always wished for nickels...

I have a set of Nickel 15x9 6uls I will sell... of course they were spraybombed black...

So what I am saying is my offer is of no use to you.

Sandblast and paint them...

:rofl:

Needs more acetone

Wheel Tech
""Gen III can be identified by the VIA stamp near the valve hole.""

https://www.miataturbo.net/attachmen...ine=1380823971

""The JWL standard (Japan Light Alloy Wheel standard) is a set of requirements for alloy wheels set by the Ministry of Land, Infrastructure, Transport and Tourism (Japan) that must be met for all passenger cars in Japan. The JWL mark, cast or forged into the wheel, indicates that the wheel has been self-certified by its manufacturer to meet the standard. There is a related standard, JWL-T, for truck and bus wheels.
The Vehicle Inspection Association of Japan (VIA) independently tests wheels for JWL or JWL-T compliance. Wheels that have been tested will bear the VIA mark in addition to the JWL mark.""

/threadjack over

I'm pretty sure everyone is out on the15x8 nickels, but if you can't wait, you might try checking with Savington and see if he still has any of the silver left. (disappointment aside)

https://www.miataturbo.net/trackspee...neering-74411/

There are some places that still have some silvers, but I'm sick of the nickels ALWAYS being sold out.

Anyway, here's a picture of the biggest crack for anybody that cares. https://www.miataturbo.net/attachmen...ine=1380836357

It really doesn't look that bad with that picture, but I tried.

Creative solution:

• Buy two silver 6UL's in whatever size you can find (used or new).
• Attend your cone chasing event.
• Buy four (or five) nickel 6UL's when they become available this winter.
• Sell the mismatched set of silvers to some Honda or Mini Cooper kid.
• ?????
• Profit.

:hustler:

That looks plenty bad. I need to clean up some used wheels I just bought and double check them before the next event.

All I can say is YIKES!! Agree with Scrappy. That looks bad.

Get 15x9 and be done with it ! Who really care about color..... function over form

I have a set of nickel 15x9s with my Hoosiers on them -- the paint lasted maybe a month before it started chipping off. I don't really care because they're race wheels, but I've heard from several other people that the nickel paint is the least durable. (I've also heard this has been improved since then, but that it's still something of an issue).

--Ian

Anyone else think this thread title is a bit misleading?

Not really fair to the 6ULs. More like 'I didn't listen to Emilio and fucked up my wheels' for a title.

Btw, just go 15x9.

15x9s are even more sold out.

And the thread title is pretty precise; my wheels, which are 6ULs, failed, and I need replacements. I take full responsibility in my original post.

No its not misleading. Wheels fail, it happens from cyclic loading. Its not like he's blaming it on emillio. I wouldnt blame the powder coat either, they were probably cracked under the paint already and it just hadn't cracked the paint yet. RE nickle 6ul, they're heavier that the other colors, why would you ever buy them, ounces are precious.

No, they weren't cracked under the paint. Sandblasting a lightweight race wheel is a no-no. The 4th wheel that did not get sandblasted but saw the same use was not cracked. If a wheel cracks, regardless of brand, you can almost always see it through the paint.

Not if its Adamantium based paint!

I'm hoping by this point there's a big warning on your site about a wheel's sensitivity to sandblasting and powder coating? I think you've had a few customers try one or both.

Says powder coat voids the warranty, but that's all I've seen so far.

Let's be clear here, I knew the risk when I had these sandblasted, the point of this thread is to help me figure out which wheels I want next. I guess I'm sort of guilty of a sensationalist title to try to get people in here, but it seems to have worked.

Ian, which generation were those?

They have the stamp next to the valve hole, so by the description earlier in this thread they must be 3rd gen.

They live a hard life -- cycled on and off the car at least once a month, and I'm probably not as careful about installing them as I could be. I don't blame anyone, they're race wheels and I'm OK with that.

That said, the Kosei K1s that served this duty before I bought the 6ULs, and the TD wheels with the street tires on them (which get swapped just as often, only the other way) don't have the same kinds of issues with paint chipping. I bought another set of 15x9 6ULs a couple months ago (these will probably be street wheels), and I went with silver this time, for cosmetic durability reasons.

--Ian

Should have galvanized them instead of blasting and painting. Set a new trend rather than repeating a failed old trend. ;)

Whoops, misread.

Ive Aircraft strippered spraybombed wheels before, and the powder coating underneath was left untouched, and undamaged. Still might be a good option depending on price though.

1) How is it that the sandblasting cracks the wheels? I'm admittedly ignorant on the finer points of metallurgy but that sounds counter intuitive.

2) I am on the verge of buying a set of used 1st gen 6ULs (15x9) that have been raced with r-comps for a good while. How worried should I be that they will crack? If they are cracked, will it be visible to the naked eye?

3) How is one supposed to change the color of powdercoated wheels if you can't sandblast them?

Thanks.

That looks pretty fucking bad. Now my butthole is getting all puckered at the thought of buying used wheels.

1. Sandblasting or sanding cuts the surface of the metal leaving sharp edges on a microscopic level. These sharp edges act like stress risers and can become the starting point for cracks. It is similar to drilling holes in your brake disks . . . great way to start cracks.

What is interesting is that a similar process, shot peening, has the opposite effect. The difference is the media. Sandblasting cuts while the steel shot used for shot peening "dents." The "denting" hardens the surface. A lot of internal items in the MSM are basic NB parts that have been shot peened. Go figure!

2. I'd be worried. Defer to Emilio's write-up on how likely/visible it is. Based upon this thread, it looks like it would be pretty visible. BTW, what's your life worth?

3. Dunno. I personally buy new wheels in the color I want. I like Silver which makes things really easy.

6uls have never been powder coated. They've always been painted as far as I know.

Thanks for the info. I'm not necessarily looking to paint the used 6ULs I'm planning on buying. The reason I'm buying used is because it seems like every time I'm ready to buy new, I can't find the ones I want. Also, the vendors who sell these wheels don't exactly have a "fall all over themselves to help customers" kind of attitude.

So if sandblasting causes the aforementioned problems, how can they hold up to any type of curbing or catching a rock, etc.?

I have faith that you guys have accurate info (read: I'm not saying you're wrong) but I just can't wrap my mind around the idea that you can have a wheel that is perfectly fine, hit it with some sand, and then it cracks like that.

I'll let Emilio speak up with the proper terminology, as it's been a few years since I last heat treated something. But basically it has to do with the sand blasting rearranging the particles of the metal, and the fact that it covers the entire surface, vs. a single rock or two.

A search on the interwebz didn't turn anything up. I'd love to know more about it from Emilio, but I strongly suspect that his explanation will be as painfully concise as all of his other responses. :-)

Here are some facts for you on cracked/replaced wheels, Mr.E.G.:

Read mattyj's post:
NWP4LIFE: ***949Racing Wheel Thread***

Basically has to do with how "sharp" the cut is. In fact, common practice to stop a crack in sheet aluminum is to drill a 1/8" hole at the end of the crack. That's enough to spread the load and stop the crack.

I would think if you caught a hard/sharp enough rock with a spoke, it could create a stress riser that could eventually lead to a crack.

Curbing usually nails the outer edge of the wheel rim. This part is not as highly stressed as the spokes or where the spokes connect to the rim.

Incidentally, another type of cracking that affects aluminum in particular is fatigue. Fatigue is all about cycles. A spinning sheel negotiating a curve is an ideal stress cycler (stress one way when the spoke is near the ground, the other way when the spoke is at the top of the fender, etc.). Fatigue cracks happen even to wheels that are otherwise completely undamaged.

yeah, you have probably done this many times with a paperclip, bending it one way then the other untill the metal work hardens and becomes brittle and cracks and breaks in two

Fatigue in aluminum is different than this. Steel doesn't fatigue.

What you are doing with the steel paperclip is cycle stressing beyond the elastic deformation range into the plastic deformation range (fancy way of saying bending, LOL).

With aluminum, even if you stay well within the elastic deformation range (i.e., put stress on it but far below the stress that causes bending), given enough cycles . . . POP . . . failure. Look up the DeHavilland Comet on Wikipedia. That will show you some really catastrophic aluminum fatigue failures.

Steel will fatigue if you stress it too much. What you can do with steel is design the part such that it doesnt seen enough stress to fatigue fail, ever. Where as with an aluminum part it will fatigue fail no matter how much you over build it, though it might just take a really really long time.

I see what you're saying, but it's not technically correct. Still does fatigue, but there is a point in the design size of steel where the fatigue like becomes infinite. Aluminum can approach that, but can never actually reach it.

I doubt that makes sense, but hopefully it does.

Edit: leafy said it better.

Agree. Leafy said it better. What I really wanted to get across was that AL has this unique property and we need to be cautious with AL track wheels that have a lot of time on them.

Okay, we all stop posting, send Leafy our comments and let him re-word them to be more clear and concise. Agreed?

lol, yall.

Partially related:

What were the offsets available on the first-gen 6ULs? I seem to recall two options, but I don't remember what they were.

+40 and +36, IIRC.