Joined: Oct 2002
Posts: 1,368
Likes: 93
From: Los Barriles, Baja Sur, Mexico
Bikes: Look 585, Kirk Terraplane, Serotta Ottrott, Spectrum Super Custom, Hampsten Carbon Leger Tournesol
If you're referring to the way a manufacturer states the size of their frame, there is no 'standard' of frame measurement.