Originally Posted by desconhecido

The Panaracer Col de la Vie is usually marketed as 26 1 3/8, but it is fatter than normal 26 X 1 3/8 tires and actually says 26 X 1 1/2 on the side wall. That's some confusing right there. The ISO seems to be 40-590. Schwalbe has a Marathon Plus that they designate as 42-590 which may be about the same size as the 40-590 Panaracer, but I've never seen one and can't say for sure. Tire width designations are confusing, too.