Your story kinda sounds like what happened to me on memo. weekend. The one day that i decide to ride by myself and the day that isnt the busiest. I decide to go to a nearby hill and take one last run up it, next thing i know the front sproket came off at the top of the hill. I just coast it back down the hill and go to some shade. I sat for about 20 mins calling people that i was camping with, until shee4speed comes and tows me. I didnt know it was him until a couple days ago. But its always best to ride with someone else and not by yourself.