Making the Crank Arm

 Creating the crank arm

I selected the inside of the sprocket and then created a spline going up toward the pedal and after adjusting the spline to make it curvier I extruded along spline and set the taper amount to -.4 and set the segments at 7. I then created a cylinder at the end of the sprocket arm. I moved the pedal so it lined up with the arm. Finally I repeated the same process on the other side of the bike to get the second pedal and crank.