Howdy,

I was overhauling the rear Normandy hub of my Motobecane Grand Jubilé today and after cleaning, noticed an unusual mark in one of the cones. It appears to be either the result of brinnelling or corrosion. The mark is deep enough to catch a fingernail. Although over 30 years old, the grease was in good condition before cleaning. I've maintained proper adjustment of the cones over the years. Although a few of the rear spokes have been broken through fatigue in the past year, AFAIK there has never been a severe impact to the rear wheel; certainly nothing enough to damage the rim.


I have two questions:

1. What is the probable cause of this damage?
2. Any suggestions where I should look for a replacement cone? The ball bearing diameter is 1/4" and the cone minor diameter is 1/2". The axle diameter & thread pitch are 10mm x 1mm.

Pictures of the Normandy hub are included for reference. Thanks for any help!