Originally Posted by
terrymorse
When considering tires, it's unequivocal. Switching out the OP's Schwalbe Marathon (Crr 0.00638*) tires for a low rolling resistance set like GP5000 (Crr 0.00321*) will make anyone faster (for the same effort).
* - Crr values from bicyclerollingresistance.com
Best Bike Split is good for showing the potential time gain on a specific road course. I would certainly consider it a significant gain switching from Marathons to any premium road race tyre.