i have a 2002 specialized p.3 with a single speed in the front and i want to put a bashguard on it. I was wondering what type i would need and how it mounts. the bike has a 4 arm crank that has a 104mm crank bolt circle diameter. It needs a new sprocket anyways becasue the current one is bent. oh and it does have truvativ chain rollers on it so i dont know if those make a difference either.