Originally Posted by
The Chemist
I have to disagree here. I switched to regular Schwalbe Marathons this year when my 5 year old Specialized Armadillos started falling apart, and the Marathons roll much better than the Armadillos did - my average speed has increased by more than 1km/h since I switched tires.
Switch to some GP4000s and you might gain another kph.