I wish I knew, stumbled on it looking for a fat 650b tire - I'll go hunting again - nice thing about The CABE, it permanently archives photos used in your posts.What kind of bike is this? That is.....wow!
What you gain with fine casings even in clinchers is, like a high-grade tubular, the carcass spreads the road shock farther through the casing, and less through the frame and fork.
On cold mornings you can tell the difference between the U of a clincher and the perfect doughnut of a tubular.
All my friends have come around and are ex-teeth-chatterers, now also riding on clouds.
The smallest tires I ride are 27mm, and those are the hand-glued with 320 tpi linen-polyester casings.
It's always wise to mount the widest tires that give good clearance on your bike.
Especially if you believe Jan's logic, most "racer wisdom" is myth, though the aero factor is a worthwhile argument.
Racers need every edge they can get, because they often win or lose by seconds - the rest of us go plenty fast and still out pace most people on their skinny hard tires.
as far as pressure goes, a tire that conforms to the road surface is faster, though many people believe their senses that ragged-edge road chatter is faster.
In reality, the tire loses momentum every time it leaves the road, and has to catch up when it recontacts, so high-pressure-induced road chatter is self-limiting on speed.
An important point about Berto chart for tire load and pressure, optimizing the contact patch can quadruple the life of your tire tread. This is somewhat important if you're buying high-dollar tires. Too high pressure, you're not riding as fast/efficient, and your tires wear out in one-fourth of the miles.
And not just low-frequency cracks and bumps - chatter is the tire bouncing over the high frequency finer features in the road texture....You're saying harder pressure tires can actually 'bounce' over bumps and cracks and therefore lose speed?