[Mark's M]

That's correct. 6-8mm clearance I believe. More than the size of your average pebble. I don't want 20's either, they do absolutely nothing for performance and add unnecessary weight. But if that's what BMW comes up with for a fix, I'll take it. I was somewhat forced to take the CCB's as a part of the amazing Canada euro delivery experience this year and tried to negotiate them out. They couldn't do it and over a couple of weeks I accepted the fact and was actually quite excited to be getting them. And then this thread popped up. I was hoping they didn't come with complications (beyond what I've researched which I was more than prepared to accept) but this issue has deeper implications IMO.

Thanks for the updates Geordie, appreciated.