I noticed that my drive belt is tracking towards the inside of the rear pulley yet it will wear magic marker marks off the outer side of the belt nubs from rubbing on the drive pulley outer side shield that keeps the belt from tracking off the outer edge of the front pulley. Anyone notice their belt rubbing one side more than the other? Not real hard against the side of the front pulley but it does remove the silver marker marks pretty much and the marks that i put on the inside edge of the belt stay untouched. Maybe the belt tracks towards the outer edge from engine torque?

 

By design, belts track slightly away from the wheel when moving forward, slightly towards the wheel when backing up.

 

My 1998 Fatboy does the same thing, drove me nuts trying to figure it out. Axle alignment is critical also, down to the 1/16 or less of an inch as well proper belt tension. Its really odd, apparently as Stiggy says, it is by design. I wonder though if the drive sprocket is tapered or what is it that causes this? Anyone know?