Heavy tracking? Check your hubs/ bearings!!

[NRBRNG]

Hey.
I know we all check things diligently after every track day, however some things are only really possible to check when other things are being replaced/ or start of season.
As part of new rotors/ calipers going on, I already had 4 new hubs inbound. Look at what i found on a my front hub/bearing...! The crack was all the way around except for about 1.5 inches. This was not there when I last replaced the rotors (< 2 years ago...) it was a new OEM hub/bearing 5 years ago...
Needless to say, this would have been an epic off if it failed on me- of course under heavy braking. Car is 100% track and runs slicks.

Still, CHECK yours when you can!

As part of my preventative maintenance, I had already ordered all 4 new hubs with press-in studs from Core4 Motorsports https://www.core4motorsports.com/pro...onversion-hubs
They come with a good reputation and use OEM hubs and options for press-ins. (No affiliation).

BTW, I will be posting some EXCITING news of my new project build and pics in a few weeks. More soon!
Cheers, Mark

[PrimeBMW]

I was in the shop yesterday. Things are coming along nicely!

[Richbot]

Jesus

Good catch - time to put those puppy’s on a pm schedule

[SYT_Shadow]

That is scary as shit

The same thing happened to Mr Bone dogbone

I'm replacing my front hubs for the Future Classics F8X retrofit kit so I can run 14mm studs. I'm convinced that is the only solution to studs breaking... and clearly the hubs themselves need to be changed every now and then

The day I do a diff I'll get the rear hubs replaced as well!

[Redd]

Damn. First time I've heard of the wheel bearing lasting longer than the hub.

[dogbone]

Originally Posted by SYT_Shadow

The same thing happened to Mr Bone dogbonel!

I discovered mine a month after a high speed sideways off at Willow Springs in Turn 9. It cracked like yours, but all the way around. My tech said that the hub actually spun slightly and then re-locked into place. After a session, I heard a clicking as I returned to the pit. I checked it out and I found two broken studs. I removed the rotor to deal with the studs and then saw that the hub was cracked......blah.

[NRBRNG]

As the saying goes, "there is always something broken on race car- we just haven't found it yet!"

[tdott]

Ah, recently changed both of my front hubs. Glad I did.

I considered doing the F8x upgrade at the time, but they seem like a bmw only part at this point. Once *** or other good option comes out, it should be a more cost effective upgrade at-least for the fronts.

But definitely guys running slicks or having trouble breaking studs/hubs should consider it.

[OG Shark]

Good catch! Can't wait to see the build - going to be epic!

[slicer]

Damn - I'm glad you caught this. Makes me want to prioritize my hub replacement!

[gills]

wow! That's definitely hairy to say the least. Good catch.

Did you receive/read the informational packet I sent? Hopefully it makes sense (Tom from Core4 here).

Originally Posted by SYT_Shadow

That is scary as shit

The same thing happened to Mr Bone dogbone

I'm replacing my front hubs for the Future Classics F8X retrofit kit so I can run 14mm studs. I'm convinced that is the only solution to studs breaking... and clearly the hubs themselves need to be changed every now and then

The day I do a diff I'll get the rear hubs replaced as well!

Going 14mm thead-in will definitely add some safety margin from a pure size increase, but it's not the only solution. They still break and still have the same stress concentration at points of peak bending stress inside/flush with the hub that is inherent with all thread-in studs regardless of features that stop them from screwing into the hub more.

Here's some failed 14mm thread-in studs on a 997 Porsche track car with only 4 HPDE's on the studs that someone recently shared with me:






An E46 M3 with an M14 upgrade also lost their wheel at my last AER race at Mid-Ohio in October.


It's safer using OEM style wheel bolts than thread-in studs. Even extended ones when using a wheel spacer.

Also, BMW knows that the clamping force/strength of a high strength 12mm stud is sufficient to do the job as that's what comes on their M4 GT4 cars and M240iR:

https://www.apmotorsport.co.uk/produ...4-gt4-stud-kit


Really, the 'ultimate' solution is to run 14mm press-in studs, which we've been working on, but aren't convinced it's necessary considering the strength capacity of high strength 12mm press-in studs.

But, we know that people are dead set on 14mm so we're looking to move forward. We're using a combination of F8x hubs and E9x hubs, which brings the cost down and is likely to be the most robust solution on the market.




We may be looking for some initial takers for testing. If anyone is interested, you can email me at info@core4motorsports.com

Sorry for the tangent.

[Estoril Blue]

There appears to be a fair amount of corrosion at the failure point. I don't think I'd be comfortable with that much corrosion on my hubs.

[aus]

Do you get any noise with bad bearings or hubs?
I've been getting a slight humming sound from what sounds like my front RIGHT wheel that is only pronounced around 60 mph and up.
.

[b4hand]

Originally Posted by gills

We may be looking for some initial takers for testing. If anyone is interested, you can email me at info@core4motorsports.com

Sorry for the tangent.

Are the e9x hubs drilled out to except 14mm studs? I would figure this would be a viable solution, but not 100% sure. Just knowing that the f8x hub is very similar could mean it's possible

[gills]

Originally Posted by b4hand

Are the e9x hubs drilled out to except 14mm studs? I would figure this would be a viable solution, but not 100% sure. Just knowing that the f8x hub is very similar could mean it's possible

They are E9x fronts that I treat similarly to how I modify them for 12mm press-ins like NRBRNG shared in his pictures. There will be a couple of things I do a little differently due to constraints.

[tdott]

Originally Posted by aus

Do you get any noise with bad bearings or hubs?
I've been getting a slight humming sound from what sounds like my front RIGHT wheel that is only pronounced around 60 mph and up.
.

Could be the bearing, take the rotor off and turn the bearing, you can usually feel it if it's bad.

[SYT_Shadow]

if only replacing the rear hubs was a bit easier...

[b4hand]

Originally Posted by gills

They are E9x fronts that I treat similarly to how I modify them for 12mm press-ins like NRBRNG shared in his pictures. There will be a couple of things I do a little differently due to constraints.

I gotcha. Well I am going to start my hpde season end of March. I'd be willing to test a set

[roastbeef]

i'm looking at replacing my hubs soon. wheels are starting to stick (rust) and my studs will be due soon. i'm likely going to do m4 hubs with titanium m14 studs/nuts.

i'm curious why one would want press-in over threaded? you can swap out a threaded stud with much less effort.

[romero1990]

Originally Posted by gills

wow! That's definitely hairy to say the least. Good catch.

Did you receive/read the informational packet I sent? Hopefully it makes sense (Tom from Core4 here).

Going 14mm thead-in will definitely add some safety margin from a pure size increase, but it's not the only solution. They still break and still have the same stress concentration at points of peak bending stress inside/flush with the hub that is inherent with all thread-in studs regardless of features that stop them from screwing into the hub more.

Here's some failed 14mm thread-in studs on a 997 Porsche track car with only 4 HPDE's on the studs that someone recently shared with me:

[img]

View post on imgur.com

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[img]

View post on imgur.com

[/img]
[img]

View post on imgur.com

[/img]


An E46 M3 with an M14 upgrade also lost their wheel at my last AER race at Mid-Ohio in October.


It's safer using OEM style wheel bolts than thread-in studs. Even extended ones when using a wheel spacer.

Also, BMW knows that the clamping force/strength of a high strength 12mm stud is sufficient to do the job as that's what comes on their M4 GT4 cars and M240iR:

https://www.apmotorsport.co.uk/produ...4-gt4-stud-kit


Really, the 'ultimate' solution is to run 14mm press-in studs, which we've been working on, but aren't convinced it's necessary considering the strength capacity of high strength 12mm press-in studs.

But, we know that people are dead set on 14mm so we're looking to move forward. We're using a combination of F8x hubs and E9x hubs, which brings the cost down and is likely to be the most robust solution on the market.

[img]

View post on imgur.com

[/img]


We may be looking for some initial takers for testing. If anyone is interested, you can email me at info@core4motorsports.com

Sorry for the tangent.

the stud failure shown from the Porsche is due to snapped(elongation+shearing) lug bolt. Looks like a few mm into hub. a pressed in lug only solves the problem when the lugs come loose. I don't see how it will address the snapping failure mode. unless you are going with much stronger lug material

[roastbeef]

Yea, you'll still see that one guy torquing his hot lugs between sessions. I don't think the pictured break is a coincidence. the landscaping tucked here and there in the carnage also tells a story.

[PrimeBMW]

I was looking into these for my E46 M3 last fall but don't think they were available on short notice. Unfortunately.