I have recently taken up bike riding as a way to stay fit. I dusted off  my old Trek 4100 trail bike last month and put it to good use. I changed  the tires to ones more suitable for the road, then started riding early  weekday mornings (as schedules permit) and occasionally on the  weekends.  I also decided that I wanted to try a "group ride", where  hundreds of cyclists get together and go on a long ride. My original  plan was to ride 30 miles in the group ride, but I ended up doing 50  miles!  Here is the story.