Vittoria Randonneur

Naturally I'd think so had it not been for Sheldon Brown (and some help from other people on the forum);

Competitive pressures have often led to inaccuracy in width measurement. Here's how it works: Suppose you are in the market for a high performance 700 x 25 tyre; you might reasonably investigate catalogues and advertisements to try to find the lightest 700-25 available. If the Pepsi Tyre Company and the Coke Tyre Company had tyres of equal quality and technology, but the Pepsi 700-25 was actually a 700-24 marked as a 25, the Pepsi tyre would be lighter than the accurately-marked Coke 700-25. This would put them at a competitive advantage. In self defense, Coke would retaliate by marketing an even lighter 700-23 labeled as a 700-25.