On another thread for Calvin's Challenge I noticed what I considered an odd requirement: all riders must have either a helmet-mounted or bike-mounted mirror. http://www.calvinschallenge.com/category/rules/ They seem pretty adamant about it.
My first year or two of biking I used to wear a helmet-mounted mirror but I didn't use it that much so when it fell off my helmet I never bothered replacing it. Maybe I'm fortunate in where I ride (Chicago and North Shore) that drivers are pretty considerate of bikers but I've never found the need to know what's going on behind me. I rely on my ears to hear cars approaching (no iPods for me!) from the rear and I'll make a quick turn-of-the-head if I need to make a left turn or cross a lane.
I'm not faulting the race organizers. They are obviously much more familiar with the road conditions in and around Springfield, Ohio. I just haven't seen that many riders with mirrors so it caught me by surprise. My question is, how many of you use a mirror and how do you find it useful?
** mp **