hi guys im new to this and im in need of some help please. I have a bike with a single sproket on the front and 8 or 9 gears to use. it has a rear mech etc. my crank which joins onto the front chain ring has broken (where it bolts to the crank) . and i am wondering if this setup is correct ? i thought that it should have multiple rings on the front chainset? or a front mech ? can some1 please shed some light please !