Duane Ausherman wrote:
Ken, I was out of the biz after 80, so I won't bet a penny on this answer (guess) or any other. I think that the steel insert started being used by the factory in 1981.
Duane, I just went out to my shop and looked at my '78 R100S (Touring). You saw that bike during this last (May) rally at my place. It was one of the two bikes that Randy and others kindly dragged out of deep storage in the dark scary dungeon at the end of my shop. It just dawned on me that I do have a snowflake wheel (or two) to look at. I'm the second owner of this '78S bike and it is original at 18.7K miles. The owner bought it for his honeymoon and then it spent most of it's life in a storage building. After the second time taking the bike to the shop to get the carbs de-varnished he decided it was time for him to sell it.
This bike has the original recalled front wheel that has never been been replaced.
I got down on my knees (not a usual position for me) with a flashlight, and examined the L/H side of the front wheel hub. I could clearly see a steel insert, turned dark with oxidation, next to the bearing/and seal. There was a slight step between the aluminum of the wheel and the steel insert.
Then I went to the other side of that same front wheel. There I saw something that I couldn't figure out. I saw traces of the steel insert and what looked something like aluminum bondo that had flaked away. Then I finally figured out what was happening. The "inserts" weren't inserted. Rather they were put in place as the wheel was cast. In the case of "flaked bondo" the aluminum over the step had broken away. Thus in some places I could see the insert and other places I was seeing the cast aluminum and parts of the insert.
Then I moved to the rear wheel. I only looked at the exposed L/H side of the wheel since the R/H side was hidden behind the final drive. And I wasn't willing to pull the axle and tire for a close look at the drive side. But the L/H side told the same story. I could see the grey oxidized "insert" and the bearing/seal inside of it. And I can't imagine that BMW would have two "styles" of snowflake wheels, with steel insert and without.
So we have a conundrum. You have me reporting that both the front and rear snowflake wheels have steel inserts in them--as of the '78 model year anyhow. And we have at least on person reporting that there is no steel insert. Perhaps a few people reading this topic could go out and take a hard look at their snowflake wheels and report back.
I could go buy a magnet and try it on the wheels, but due to the close proximity of the bearing/seal I'm not sure I would get a definitive result.
I don't like mysteries, even in books.
Ken