[SuperMacGuy]

I was at Summit Point yesterday for FATT. During my 2nd heat I had my left front hub fail. It let loose in turn 5-6 or so, and if you know Summit, that's about the slowest part of the track. Which is right after the part of the track with the highest pucker factor IMO (downhill at 80-100 depending, about a 30 degree turn a little off camber and max braking soon as you're through it). So I am OK and there is no body damage.
The hub flange sheared right off, and the wheel getting pushed back it must have bent up either the brake caliper or the slide pins, the caliper doesn't float any more. A guy with a TA next to me thankfully had a spare hub, so I got that on and drove carefully home. This was a Mike Minear hub so I'm contacting him to see if he wants to inspect it. I'll probably get a new one from him over the winter.
I'm thankful that was all relatively low drama. If that happened almost anywhere else on track, well all the other places are pretty high speed, and it would've been a real wreck, literally.

Chris

[SuperMacGuy]

I talked to Mike several days ago. Here's some of what came out of the conversation. Some of this is paraphrasing and some is sort of restating what Mike posted earlier.
Pete's analysis showed that the parts were not forged well enough (if forged at all), that they were almost as porous as a cast piece. Pete said they looked like (more or less) just a fatigue break, and did not have any particular defect that instigated the breakage; simply the rotating stresses wore it down "like bending a paper clip till it breaks". Mike designs them, and another company buys axle blanks and essentially cuts off the long part of the shaft, and then does machining to the specifications. The machining company was contacted (if I remember he said that) and is supposedly changing suppliers or making some other adjustments to get better quality pieces to start.
Mike said he has a couple options he is looking into to improve the part.

1. Redesign the hub to have a thicker/wider radius at the transition area and/or thicker at other areas. His primary problem is finding a suitable grease seal from an off the shelf application. Says having a custom seal produced would cost a fortune.
2. Better quality part to start, and proper heat treating and hardening. (In regards to this I suggested examining the "left over" part of the axle to verify it's been forged of proper strength. I think Mike said that's not entirely feasible due to what happens to metal under heat treating or cutting it apart. We had some technical discussion that I do not remember some of the exact details of; I may be mis-remembering this particular part of it.)
3. Induction hardening. Mike says this could costs thousands to set up and require a lot of blanks to do trial/error setup of the induction unit and cutting/testing of several to optimize the hardening. But would be a really good way to harden the part, too bad it's so expensive, it probably won't happen due to cost and what is probably low demand of this part in general. I suggested a group buy on hubs, Mike thinks the demand is probably still too low to justify or cover the high cost of it.

His dye penetrant test on his hubs showed no visible cracks or stress on his unit. Though it was probably made in a different batch of hubs than mine was.
Mike has not been able to take off work recently to visit suppliers or shops during daytime business hours, so this has been sort of a slow process.
Mike said it was OK to post this and I hope I am posting everything correctly. If not I'll be happy to edit or post corrections after the fact.