er,,sprinting with ONLY front OR rear panniers. When commuting along at 12-15mph and you want to get to the turn or in line with other vehicles going 20-25mph one sprints from a cruising velocity, there's no sprinting from a standing start. Out of the saddle,pulling on the bars, whether going slowly up a hill or quickly on the flats torques the frame differently than sitting and pedaling hard. The OP criteria seem to be commuting and fast riding. The CC handles much better with load on the front with out of saddle efforts.