The International Standard Chain Guide (ISCG) mounting system was developed by a number of companies to achieve a consistency across the frame manufacturing board in 2003.

While the original ISCG standard worked for a number of years, current frame manufacturing and component designs now demand a more rigorous standard.

As a result the newer ISCG’05 standard was developed by drivetrain component and frame manufacturers to accommodate the need for more strict guidelines and better compatibility.