A couple of suggestions:

Customiser: Significantly alter a bike in some way.
N-1: Destroy a bike.
Heavy Haulage: Transport goods exceeding your body weight.
Preacher: Successfully convert a motorist to cycling.
Who Needs a Boat?: Ride a flooded road.
Foreigner: Ride across an international boundary.
Explorer: Discover every map location in single player mode (just kidding)