I'll have to find the reference (J "Bicycling Science" maybe?) but I believe the evidence is that wider, lower pressure tyres have less rolling resistance on re

I'll have to find the reference (J "Bicycling Science" maybe?) but I believe the evidence is that wider, lower pressure tyres have less rolling resistance on real world roads. If you're going fast then there's an air resistance trade off to make, but even for something like the Tour de France I'm told the modern preference is for 28mm tyres & for us ordinary riders wider than that would be the optimum width. You don't want knobbly MTB tyres on road though obviously.