I can't add to some of the wind velocity stories above, or the broken ribs/puntured lung, however, 4 weeks ago returning from a 3 hour ride with a tailwind and then, after feeling like a stud, I rode 75 miles into a 15-20mph wind with gust of 25 to 30%. A gust on a down hill slowed me from 14 mph peddling downhill to 7 MPH. It took me 7 hours to get home. It was a 7 hour ride uphill, or so it seemed.