So this image has floated around social media for a couple of days. ND track toy on 200tw tires running 949 6UL 17x9 wheels. No contact, no impact, but 1/2 way through the second set of tires the wheel failed catastrophicly on track. Thankfully the driver was unhurt. Upon closer inspection the other three wheels showed a lot of cracks.
Here’s the issue. When he reached out to 949 about it they essentially told him to pound sand and didn’t ask for the wheel back until after it went “viral”. Apparently the guy later reached out to FM who is going out of their way to make things right (good job Keith!)
I don’t run a company but if I did I would hope that my response would be to offer to buy back the wheels and figure out what caused the failure so I could improve my product and NOT see this again. Apparently 6ULs have been having a pretty large number of catastrophic failures lately. Businesses like this live on their reputation and being proactive about problems and good to their customers would be the smart play. 949 has apparently dropped the ball on this one.
They can fix it by putting these words in their ad, "Street use only, not for Motorsports."
Yeah, I'm a cynic sometimes.
I inspect every track wheel for cracks EVERY TIME they are off the car.
Im not defending the manufacturer, but a comprehensive pre-track inspection should have shown the impending failure prior to catastrophic failure. This is on the guy that signed the tech inspection form as well as the manufacturer.
Actually, track use does void the warranty on the wheel. You can read it on 949Racing's website. This set did see a fair bit of track use, but not as much as some of our shop wheels did. This failure happened quite a bit earlier than I would expect.
It's interesting to see how the story has changed a bit in the retelling across various platforms. 949 does want the wheel back for analysis. There have not been a pretty large number of catastrophic failures lately, there's one other relatively recent failure of a different 949 wheel that has been extrapolated into "a large number". There were problems with the "Gen 2" wheels a few years back, though. Witch hunts are fun and 949 is not very good at customer relations, neither of which should be a surprise to anyone who's been around.
FM sold the wheels, so we're standing behind them. But we're also recommending that any of these 17x8 and 17x9 ND wheels be inspected carefully especially if they've seen track use. Seth, take a look under Rufus just in case.
It's interesting to see how the story has changed a bit in the retelling across various platforms.
Ah, the voice of reason. Keith, you do it well.
In reply to Keith Tanner :
Will do. Thanks.
I suspect what will come out of this will be a greater awareness of the need to inspect wheels regularly. We're doing a Facebook Live video tomorrow on the need to inspect older wheels - for example, that rare set of 20 year old lightweight JDM unicorns you might have found may no longer be viable.
And obviously, we're going to be taking a close look at this particular wheel design. It appears the cracks are originating on the backside of the spokes - you can get an idea of the general area from the photo above.
https://www.trackjunkies.org/topic/6180-my-wheel-broke-at-100-mph-wtf-are-wheels-really-wear-items/
https://forum.miata.net/vb/showthread.php?t=617408
http://www.hialexkim.com/blog/949racing-6ul-wheel-catastrophic-failure
I don’t think it’s a “witch hunt”. A quick google search turned up these three and it’s only because i’m lazy that i’m not linking more. And it’s not an indictment of FM, they’re awesome and Keith is the man. Emilio and 949 otoh could use improvement.
“Wheels are a wear item” is some weak sauce excuse, if I have to replace my wheels at every other tire change it’s a really false economy to buy lower cost wheels. (And I do know, personally, a guy whose 6ULs cracked under autocross only conditions.)
It feels like the metallurgy needs help and they need something that will bend more before it breaks.
It's a cast wheel. I'd call it a wear item.
Duke
MegaDork
9/4/19 7:23 p.m.
Keith Tanner said:
949 is not very good at customer relations, neither of which should be a surprise to anyone who's been around.
I've been watching this debacle unfold since the first FB post. What you state here is the crux of the biscuit.
Are you likely to be able to see the cracks from the front? I inspected mine and can't see anything, but I didn't take them off the car. That FB live thingy going to have any cracked pre-failure examples?
Ive always found the cracks at the rear of the spokes near the hub on corvette and camaro wheels.
Toyman01 said:
It's a cast wheel. I'd call it a wear item.
At every tire change? You must be rich to afford new wheels that often.
KyAllroad (Jeremy) said:
https://www.trackjunkies.org/topic/6180-my-wheel-broke-at-100-mph-wtf-are-wheels-really-wear-items/
https://forum.miata.net/vb/showthread.php?t=617408
http://www.hialexkim.com/blog/949racing-6ul-wheel-catastrophic-failure
I don’t think it’s a “witch hunt”. A quick google search turned up these three and it’s only because i’m lazy that i’m not linking more. And it’s not an indictment of FM, they’re awesome and Keith is the man. Emilio and 949 otoh could use improvement.
“Wheels are a wear item” is some weak sauce excuse, if I have to replace my wheels at every other tire change it’s a really false economy to buy lower cost wheels. (And I do know, personally, a guy whose 6ULs cracked under autocross only conditions.)
It feels like the metallurgy needs help and they need something that will bend more before it breaks.
First link is a gen 1 wheel, so it’s close to a decade old. Second link is gen 2, which I acknowledged as having problems earlier. Third link is the same, from 2012. That’s not what I call lately and none were low hour items. Those were not “every tire change”. Google any wheel brand over a 10 year period and you’ll find failures, unfortunately.
I’m more concerned with a failure of a Gen 4 with relatively low hours, although it appears this most recent set had 1500 track miles on them and a few offs. The Gen 4 should be the strongest of the bunch due to lessons learned and flow formed construction - although flow forming won’t prevent any of these failures.
I’d recommend taking the wheels off the car, cleaning and using a bright light to inside the the inside of the spokes. That’s where the cracks were forming on the mates to that busted wheel. I don’t think we have any cracked wheels on hand, it’s not the sort of thing you hang on to.
How would anyone of us deal with it? Well I'm sure a few of us would first try JB weld. Then your next option would be coffee table.
Pop the tire. Get on with life. If you can't afford to walk away from it yadda yadda... 
Buy heavier wheels, less sticky tires, and quit hopping curbs. Or, quit buying cheap light wheels.
6UL. Bad double entendre.
Floating Doc said:
this most recent set had 1500 track miles on them and a few offs
Quoted for emphasis.
I had a problem with a 6UL wheel out of the box. Unfortunately I did not notice until the tire was mounted and we had to balance it. I put money that no one here would have noticed either.
Emilio told me to pound sand.
I did not buy it from Keith. I bought it through another Miata company who tried to help me as much as possible.
I like what 949 does, but their customer service is non-existent. I felt like they do not stand behind their product.
Oh well, lesson learned. I will buy a BBS or top tier Japanese wheel next time.
I’ll stay out of this, but note that yes: all wheels are wear items. Ask any professional race team.
In reply to KyAllroad (Jeremy) :
Not really. I don't swap wheels often, but I do go over the wheels and tires pretty closely before every event, and understand that the warranty is over as soon as the car touches the track. Pounding the curbing around the track at 100 mph is going to take its toll and any failure is on me.
KyAllroad (Jeremy) said:
Toyman01 said:
It's a cast wheel. I'd call it a wear item.
At every tire change? You must be rich to afford new wheels that often.
Not what he is saying at all, and you know that. 
Tom Suddard said:
I’ll stay out of this, but note that yes: all wheels are wear items. Ask any professional race team.
This is what I want people to take away from this. Not "OMG all 6ULs are deathtraps!", but "wheels are not forever". Obviously they should last a reasonable amount of time, but like so many other components they need to be monitored and occasionally replaced. This is particularly true if they're a lightweight wheel built for a lightweight platform.
In reply to Keith Tanner :
And even more so when it's a light weight wheel on a heavy platform. I'm running fairly cheap flow formed wheels on a 3400 pound car. I fully expect to see one fail at some point. Hopefully I catch it before it catches me.
Hopefully it's engineered for those loads. I know the 6ULs for the NC are built for higher loads than the others because it's used on heavier cars.
