Kogel Kolossos OSPW 12/19T for Shimano RX800 GRX 2x, Ceramic Bearings, Oversized Derailleur Cage

Detailed Specifications

• Brand: Kogel Bearings

• Model: Kolossos Oversized Derailleur Cage (OSPW)

• Pulley Sizes: 12T upper / 19T lower, with precision ceramic bearings

• Compatibility (Derailleurs): Shimano GRX RX800/RX810 and Ultegra RX800 series (mechanical & Di2), designed for 2x road and gravel drivetrains

• Drivetrain Speeds: 11-speed and 12-speed 2x GRX drivetrains

• Not For: GRX 1x setups — use the dedicated GRX 12-speed 1x Kolossos model instead

• Intended Use: Gravel / Cyclocross / Endurance Road / All-Road

• Materials / Build: Oversized aluminum cage with ceramic bearing pulleys and reinforced inner cage for stiffness

• Color Options: Black, Red, or Gold

• Includes: Outer and inner cage assembly, 12T upper pulley, 19T lower pulley, mounting hardware

• Warranty: Kogel Lifetime Limited Warranty

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Additional Features

• Reduced Friction: Oversized ceramic pulley system significantly decreases drivetrain drag, ideal for clutch-style derailleurs used in gravel and cyclocross.

• 2x-Specific Design: Optimized for Shimano GRX 2x drivetrains for smooth front shifting and consistent chain tension across chainrings.

• Enhanced Chain Retention: Long-tooth 19T lower pulley improves stability and prevents dropped chains on rough terrain.

• Chain Catcher Integration: Built-in chain catcher minimizes risk of jams and chain derailments.

• Gravel-Proof Construction: Engineered with stiffness and precision to handle off-road conditions without sacrificing shifting accuracy.

• Performance Efficiency: Delivers “free watts” by reducing drivetrain losses, translating into smoother pedaling and faster speeds over long rides.

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Important Usage Notes

• Compatible with Shimano GRX RX800/RX810 and Ultegra RX800 series derailleurs in 2x configurations (11- or 12-speed).

• Not compatible with GRX 1x setups — use the Kogel GRX 1x Kolossos instead.

• Installing this OSPW system usually requires a longer chain for correct wrap on 2x drivetrains.

• Adjust B-tension and confirm chain length for optimal performance and shifting precision.

• Maintain regular chain cleaning and lubrication for best efficiency and bearing longevity.

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Riding Impressions

The Kogel Kolossos RX800 2x system transforms drivetrain performance with its oversized 12/19T pulley configuration. The ceramic bearings reduce friction for noticeably smoother pedaling, while the stiff cage ensures crisp shifting even in harsh off-road conditions. Whether climbing gravel roads or racing endurance events, riders benefit from quieter operation, better efficiency, and improved chain control — all with signature Kogel durability.

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Disclosure

This listing includes the Kolossos oversized derailleur cage assembly with 12T/19T ceramic pulleys and mounting hardware.
Derailleur, chain, and cassette not included.
Genuine Kogel Bearings product, retail packaged with lifetime limited warranty (proof of purchase required).