Hey guys, i bout a Motobecane Outcast SS 29er with 03 Bomber Shox yesterday for only 275 bucks.. he gave me a few extra sprockets and also he gave me a Fixie type sprocket.

ok, i know what it is to a basic extent. i know that you cant stop peddling when its on... but why?! why do people do this? i want to know what its good for before i put it on there. do you benefit in anyway?
PLEASE CORRECT ME IF IM WRONG ON THIS! i think i am, i only started mountain biking about a mount ago
Thanks so much!

-john