Originally Posted by Dave Mayer

I got the tires for free. They refuse to die. I've resorted to daily high-speed runs on packed gravel on these 22mm tires. Still won't die.

And what do you me by slowest? Differences between rolling resistance of various tires are trivial compared to aero effects and rotating mass. When you're trying to hang on in a fast group ride on a climb.. your tongue is rubbing on your front tire, and your heart is about to jump out of your chest. You have to stay with the pack, or you'll end up suffering solo for the next 10 miles. In this situation, low bike and especially wheel weight are the overwhelming need. This is where tubulars are the key advantage.

Who cares if your wheels are 10% more aero, as 95% of your riding time will be in the pack - sheltered from the wind.

BTW: large volume tires (such as 28mm+) have the worst aero and rolling resistence. They are definitely heavier. I tried some clinchers in 28's; between the porky rims and heavy tires they made my bike ride like a farm tractor.