I could use a sanity check on this topic. We have a local route that has a downhill leg that is about 1/2 mile long. We've ridden it many times. On our old 2002 Co-motion cappuccino, we'd typically hit 50mph. On our new Calfee, we barely get to 42mph. Since we're "spun-out" in both scenarios and coasting, what's accounting for this significant reduction in speed? Same riders, road surface, tires (28c gatorskins.) Old bike had Hugi hubs/Velocity rims, new bike Spinergy TX2. The old bike weighed about 50lbs, the new Calfee is about 36lbs. Is it fat carbon vs thin steel frame? Can weight make that much difference? Has anyone else had this experience when upgrading to a lighter tandem?