The wheel sheared off the hub, as shown in the pic above - no blame attaches to the mechanic(s). In fact if you check out the photos in the linked article below, you can see the wheel starting to fail as Berger goes round Goddards.
http://www.visordown.com/motorcycle-rac ... 17617.html
And it wasn't a Ducati wheel.
It was an OZ wheel...
