Hub Failures
 

This weekend at Thunderhill three 911s ended up with broken hubs and stub axles. Two of them were sudden failures and hadn't resulted from any off track excursions. A third was a result of an accident where another car hit the passenger side wheel at a pretty good speed. Interestingly, the car that got hit, had a sudden failure of it's hub and stub axle on the drivers side, a few weeks ago at Buttonwillow.

Rumour in the pits is that the Quality of the newer hubs is a little suspect, I dont know if it is or isn't, but I'm starting to wonder if those are parts that should just be replaced after a certain amount of hours as just preventative measure.

Looks like now I'll start bringing an extra hub and axle to the track also. I'm starting to understand now, how you go from a 18 feet open trailer to a 24 foot enclosed.;)

Michael, there was a thread on this topic not too long ago, after Chris Streit broke a stub axle on his race car. Pretty scary to think that can happen at speeds during a race..or worst on a crowded highway.

Be careful out there.

What has typically been happening when the hub/stub axle breaks - does the wheel depart suddenly, does the driver have time to stop on all four wheels, or do you just lose drive to that side?

Thanks Souk, Just read the thread, thats the same failure as the three I saw. They also broke their Hubs.


John, on all three they all lost drive, but were able to pull off the track and stop without incident. The wheel generally doesn't just take off because the caliper is actually holding the rotor on. On my buddies car, he was actually in a very high speed turn (over 100 MPH) when the failure occured. The backend moved around on him, but he was able to control it and pull it off the track.

How'd the weekend go, other than that, Mike?

A POC racer named Urs Gretner has had hub failures (2) this year on his 930. He did not participate in the Tribute to Le Mans this year because he has parked the car until he can resolve the issue. When his broke, it tore up the rotor and bent the trailing arm. Not to mention that he has lost a little confidence in his race car. Not a good thing.

It was a lot of fun and very frustrating at the same time. That track really made not having a Limited slip annoying. I couldn't put any power down going thru the esses in the back and getting onto the front straight was a complete joke. But, seeing as that is really my first time getting to spend anytime on the track, (other then the little time at OTC last year)overall, I was pretty happy. I placed fifth in the race and was able to turn a 2:06xx lap times.

I have decided that I have to get my tranny done and I am not racing on Kuhmo tires anymore. The Hoosiers were making a differance of about 2 seconds on those who had both sets. With that 2 second difference and the time I would gain having a limited slip, I should be toward the front of the front of the grid, of course talk is cheap.;)

Thunderhill really is a great track though isn't it.

That's actually a pretty great time. It sounds like Hoosiers would have been the fix.

Thunderhill benefits from repeated visits, even though it doesn't seem that technically difficult. (I remember trying like crazy to crack a 2:14 there.) It's also a lot slower when it's hot, I think.