Well today i broke my rear derailleur. I really don't know how it happened but it was while i was riding. I was pissed because i left my chain breaking tool at home and i was 15 miles away from home. :x so i had to call my sister to pick me up. Now i'm in need of help choosing a derailleur for my bike. I'm clueless about what should i get. Any suggestions would greatly be appreciated.