DoctorT, We're of a mind about using what's on hand. a. I've a bunch of mirrors but all with a 10mm thread. I've looked on Ebay but I'm not sure from their vague descriptions that they're actually an adaptor rather than just an extender. Do they make them with an 8mm thread on one side and a 10mm on the other, into which I could place my 10mm mirror? I'm going to be on a 2009 RT in July in France and England, and I dread using the RT's awful rear view mirrors. On my own 2009 I just did an ugly DIY version of your conversion by drilling a horizontal piece of steel to accept the 10mm mirror, and passing an 8mm bolt through the switch housing, with appropriate locking nuts (I also used a spacer). It would be better with the 8mm to 10mm adaptor on the bike I'll be sort of renting over there from France - I don't want to mutilate it. Thanks for any thoughts you might have on this.