Hub failure

[Michael Oritt]

I ran Saturday at the VSCCA Shenandoah event--during the day's last run my left rear hub sheared in two--luckily on a slow right-hander--and I ground (literally) to a stop on the track with the left rear wheel sticking out of the axle tube with wheel attached, sort of like in the chariot race scene from Ben-Hur.

Attached find two shots of the hub--it is sliced in two like a bagel. It may be hard to see in the photos but there are four wedge shaped ramp-like fractures, each starting from where the hub is drilled and tapped to receive the little screws that hold in the axles. No doubt these holes created weak spots.

This and the other hub are of indeterminate age and I probably should have replaced them both as soon as I bought the car--in any case I ordered two new ones from Winner's Circle today and will be installing them on both sides and keeping the present right hub as a spare. Rob at WC tells me that the new hubs are machined differently with a larger radius to prevent this failure.

The only significant damage otherwise was to the end of the axle housing itself. When the axle came out it tore up the threads and distorted the end of the tube--plus I had to remove the hub with a die grinder and sawzall. I'm going to have a replacement left-end welded onto the axle tube. Has anyone ever done this and are there any tips on aligning, etc?

 

[Michael Oritt]

Here's one larger picture of one part of the hub.

 

[Michael Oritt]

And a second one.

I had to cut and grind on the hub to get it off the axle tube. But notice the ramp-shaped fractures corresponding to those shown on the inside of the outer flange of the hub shown in the preceding photo.

 

[JerryB]

You need to jig the housing to get the new stub in the housing so it's right. Chances are the housing was bent/warped before as many of them were. (just enough to suck some h.p.)

If the housing is stock width Spridget you might be better off starting over...but the chances of finding one thats straight is iffy.

There might be someone back your way that can do a setup to turn the housing end square and have the proper mandrels (big on the word might). A number of years ago I used a fellow name of Alex MacGillavey in Tucson Arizona, (520)790-3915. He does spectacular work.

 

[Bugeye58]

Michael, was this a WC dbl bearing hub??
One more thing to go on my annual MagnaFlux list!
Glad the damage was relatively minor. That could have gotten very ugly.
Jeff

 

[Michael Oritt]

Jeff--

Yes. When I spoke with Rob he asked me if the hub was black (it is)which means it was one of his. He said they had a few failures with that configuration and have since put more of a radius inside the flange. I am sure that the small holes had something to do with the failure--it is just too coincidental that each fracture started at the holes. BTW Rob also said that they only drill two holes now which makes sense.

 

[Michael Oritt]

"If the housing is stock width Spridget you might be better off starting over...but the chances of finding one thats straight is iffy."
-------------
Jerry--

Couriers use what is commonly termed a Riley 1.5 rear axle, the same as was used on Morris Minors. It is 48.5" from outside of flanges, about 4" wider than a Spridget but uses same hubs.

 

[VelodromeRacer]

Michael, Sorry to see, glad you wern't cruising at high speed. When I bought the Bugeye this summer, it had stock front spindels, rear single bearing hubs and stock axels and raced this way for 34 years!

I have replaced all with winner's circle double bearing hubs, upgraded axels front and rear, as I worry that is where failure will occur.

As my mechanic states, most people work on the engine and easy to get to items and never really spend much time under the car...when we took my rear axel/hubs out, the right rear shock mounting bolts were completly loose!! My mechanic has bought an Elva and will race next year as well.

 

[Bugeye58]

Jeff--

BTW Rob also said that they only drill two holes now which makes sense.

I can't remember if mine have two or four. I'll have to be sure and check.
Thanks for the heads up.
Jeff

 

[Michael Oritt]

Tuesday I picked up a Sprite axle tube with good ends and had the left end welded onto my tube. Yesterday new hubs and bearings from Winner's Circle arrived (still four holes!)and today I bolted the axle housing back into the car, installed the hubs, etc. etc. and took the car for a test drive. All seems good and I will be at the Turkey Bowl at Summit Point.

From chump to champ in five days--good work Batman!

 

[Bugeye58]

Good work!
I checked mine, and they're the 4 hole variant. I'll just keep a close eye on them.
Jeff

 

[Hap Waldrop]

I've ran DB hubs with 4 axle retaining screw hole for years with zero problems, what looked to be your problem was the lack of a radius on the back side. We made CNC DB hubs for awhile and at the advice of Randy canfiled greatly increased the radius in this area. Just like a crankshaft in high stress area you need a good radius or the sharp angle will create a stress riser and be prone to fail.
In my opinion, the lack of radius, not the extra two holes was your failure.

 

[Michael Oritt]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]In my opinion, the lack of radius, not the extra two holes was your failure. [/QUOTE]

No doubt and Jeff at WC said the same thing though the fact that the fractures run to the holes made me suspicious that they created weak spots--in any case I have new hubs L & R.

 

[Deleted member 3577]

Yipes!....I have the same DB ones /bcforum/images/%%GRAEMLIN_URL%%/cryin.gif

Even when I think I'm done w/ something....

 

[Bugeye58]

Dave, there are a lot of us in the same boat. I'm just going to keep a watchful eye on mine, and MangnaFlux them every year.
Jeff