27" was a British/Imperial size. 700c is a French size.
This time around the French sizing system won out. Back in the day when I started racing I was using 27" tires for clinchers and the tubular/single tires were all French (700c) sized. You generaly could use either sized wheels/tires in most frames although there is a 4 mm diameter difference. Using 700c clinchers AND 700c singles is way more convenient so I guess it won out.
Regards, Anthony
Last edited by AnthonyG; 11-19-07 at 07:43 PM.