actually, i'm a fairly experienced rider, i rode rigid mountain bikes for years, so i know how to absorb impacts. and 'ride light" I dont know what i hit, I was riding at about 30mph down a slight decline on a lighted highway WITH a bike light, and didnt see what i hit...i even went back later with my backup to find what i hit and didnt see anything...i think it might have been one of those small gas covers...but i dont really know. And believe me, after a recent rash of flats i do little but look look ahead for hazards. this one is just a (expensive) mystery. what really sucked was this was on a quick 'leisure' ride