Arc length of the bowler's initial track Distance
across initial "oil" track
Less than 10" (More than 23.5 degrees of axis tilt)
Between
10" and 10-1/2" (Between 23.5 and 20 degrees of axis tilt)
Between
10-1/2" and 11" (Between 20 and 16.5 degrees of axis tilt)
Between
11" and 11-1/2" (Between 16.5 and 13.5 degrees of axis tilt)
Between
11-1/2" and 12" (Between 13.5 and 10 degrees of axis tilt)
Greater
than 12" (Less than 10 degrees of axis tilt)
Speed overpowers rev rate
Speed slightly more than rev rate
Speed and rev rate matched up properly
Rev rate slightly more than ball speed
Rev rate overpowers ball speed