I have my Monkey Electric on my front wheel of my Xtracycle so I don't know about delicate bikes and wheel balance at speed. These lights haven't had double blind studies done on them but I have had cars stop in their turn at night, so they obviously saw them. Of course, I am 'clinging to the phrase' Be seen Be safe. It isn't a force field. One has to assume drivers aren't going to hit something on purpose.