I just got a pair of napoleon bar end mirrors to put in my rizoma clip ons. The rubber expander and nut is too big to fit in the end of the bar. I'm thinking I may either drill out the end of the bars, or possible modify the expander and nut to fit. I'm leaning toward drilling out the end of the bar since I feel like the mirrors may spin in the bars if I cut too much off of the expander and go past the point at which the little notch is in the expander. Is there some kind of adapter I can purchase? Any better ideas?