Originally Posted by
znomit
By choosing the lower rolling resistance tyre in real world terms it means that your coefficient of flats has increased by a ratio of 1.5/1.2. The average moving speed improvements are more than offset by the increase in time spent fixing the extra flats. But you now have something else to brag about at the coffee shop.
He did ask about the "real" world.
I ride on practically bulletproof tires that are on the heavy side, plus have liners in them. But I commute and need to get to work reliably. They still roll reasonably well. I don't feel the difference as much on the velo, because it's already 70 lbs, but it's more noticeable on the (recumbent) bike.
Once I get the velo up to speed though, aerodynamics becomes more important, and that's where it really shines. I had some Kojaks on my bent when I was in Tucson, and on the smooth bike trails around town, they were nice and fast, but it seems like on the surface streets, which were much rougher on average, my 'slow' commuting tires were slightly faster (and way more comfortable).