I'm none too fond of bar mirrors either so far. The ball-and-socket variety appear too susceptible to road vibration especially now that I've switched out Tank Jr.'s knobbies in favor of Invert 2 tires. I'm visiting my bike shop soon to peruse the helmet-mount mirrors available though I suspect the vent issue will present a hardship.

My reason for using a mirror isn't motoring traffic. I'm pretty disciplined about keeping line of travel and therefore pose no surprise for overtaking automobiles, and I figure that by the time my mirror alerts me to imminent peril it'll be too late to take effective evasive action. My mirror is for the detection of certain of my cycling brethren and sistern, those that see no need in announcing their presence as they overtake me. I keep up the pace when road-riding alone and so this very rarely happens (Portland's biking commuters are in no particular hurry, I've found), but come the day I find myself in a tangle of frames and wheels and flailing limbs, and I glance up from beneath the writhing form of the eejit who hit me to see a motor vehicle attempting desperately (hopefully not in vain) to avoid rolling over the both of us, I'll be a tad annoyed.

-Rob