Kolossos, derived from the Greek word for a statue much larger than its original subject, aptly describes this oversized derailleur cage. By replacing your stock 12-tooth pulleys and cage with a 14-tooth top pulley and a 19-tooth bottom pulley mounted on the stiffest cage available, you can achieve reduced friction, improved shifting accuracy, and enhanced chain retention. Kolossos users appreciate the smooth shifting, quiet ride, and seemingly effortless power transmission to the rear wheel.

The Kolossos ST model offers the same stiff, oversized cage for crisp, accurate shifting and oversized pulleys to reduce drivetrain friction. It is equipped with high-quality Kogel ST stainless steel bearings, providing excellent durability and smooth performance at a more accessible price point.

This model fits only 12-speed Shimano GRX 2X - 11 and 12-speed derailleurs. Please note that installing this oversized derailleur cage typically requires replacing your chain to accommodate the larger pulleys.