It's worth bearing in mind that even if the bearings are identical dimensions BMW were notorious for setting them up at the factory with excessive pre-load. In my case I found it was grossly excessive pre-load and I had to insert a shim which from recollection was 3 or 4 thou.
Like Monte I much admire Mike Valenti's precision approach to the measurement of bearing drag and it's a pity BMW were not as contentious. There was something else I learnt in setting up my bearings and that's the fact that unless you are extraordinarily lucky the interval between available sizes of wedding band is simply far too big.
Using Duane Ausherman's shake the wheel test I found I was easily able to detect half a thou difference in shimming while the wedding bands only came in 2 thou intervals. As I needed to reduce pre-load, rather than buy a thicker wedding band and lap it down I ended up making my own shims.
I'm in agreement again with most all points Barry - as usual. I too find the factory preload of 21 to 42 inch ounces excessive. In fact my target is much in the lighter range of 15 to 25 inch ounces. Leaning towards 15.
And I agree with your comment of the factory steps in wedding band sizes may not get you to where you want to go without milling, or shimming. 0.05mm can make you or break you if you're close to either side of the limits.
I no longer use Duane's shims (or others), just a personal preference for me. Those 0.05mm shims are very easy to overlook and loose count of. And if anyone other than myself ever get's into the stack they will surely overlook them. My recommendation if you choose to use the shims is to be sure and clearly document how many you've used in your personal records.
The well known /2 shake test is a good final test after installation but I wouldn't advise using it for adjustment alone on the newer wheels.
Just as a clarifier, as I expected - a lot of you feel I go over and beyond for this process. Most of my posts reflect my experience with testing which I was very critical of, in the way of parts, fitment and procedure. I want to share the details I've learned for the sake of completeness and safety. Most of our wheels have the steel hub inserts which make this procedure much less complicated. My testing was for the all aluminum drum brake snowflake hubs on my R100/7 for which the R&R and preload is much more involved. Shortcuts are fine, just be sure to be careful in what you do for your own safety.
