Perils of Fixie Ridin'

Luckily, I was riding on the left side of the street, kind of ambling along as I didn't have far to go between one point and a cup of coffee. When all of sudden, I felt this tug on my right leg and my foot and calf made this wierd circle pull down that was quite unnatural and painful. I hopped off in the middle of an intersection!!!, but luckily there were no fast cars and it took a quick pull to release the chain and chainrings' toothfull grip on my jeans. Apparently, I did not have my pants rolled up high enough. Thanks be to whoever I wasn't bombing down some hill.