Detailed Specifications
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Brand: Kogel Bearings
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Model: Kolossos Oversized Derailleur Cage (OSPW)
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Pulley Sizes: 12T upper / 19T lower, with precision ceramic bearings
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Compatibility (Derailleurs): Shimano GRX RX800/RX810 and Ultegra RX800 series (mechanical & Di2), designed for 2x road and gravel drivetrains
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Drivetrain Speeds: 11-speed and 12-speed 2x GRX drivetrains
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Not For: GRX 1x setups — use the dedicated GRX 12-speed 1x Kolossos model instead
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Intended Use: Gravel / Cyclocross / Endurance Road / All-Road
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Materials / Build: Oversized aluminum cage with ceramic bearing pulleys and reinforced inner cage for stiffness
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Color Options: Black, Red, or Gold
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Includes: Outer and inner cage assembly, 12T upper pulley, 19T lower pulley, mounting hardware
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Warranty: Kogel Lifetime Limited Warranty
Additional Features
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Reduced Friction: Oversized ceramic pulley system significantly decreases drivetrain drag, ideal for clutch-style derailleurs used in gravel and cyclocross.
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2x-Specific Design: Optimized for Shimano GRX 2x drivetrains for smooth front shifting and consistent chain tension across chainrings.
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Enhanced Chain Retention: Long-tooth 19T lower pulley improves stability and prevents dropped chains on rough terrain.
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Chain Catcher Integration: Built-in chain catcher minimizes risk of jams and chain derailments.
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Gravel-Proof Construction: Engineered with stiffness and precision to handle off-road conditions without sacrificing shifting accuracy.
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Performance Efficiency: Delivers “free watts” by reducing drivetrain losses, translating into smoother pedaling and faster speeds over long rides.
Important Usage Notes
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Compatible with Shimano GRX RX800/RX810 and Ultegra RX800 series derailleurs in 2x configurations (11- or 12-speed).
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Not compatible with GRX 1x setups — use the Kogel GRX 1x Kolossos instead.
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Installing this OSPW system usually requires a longer chain for correct wrap on 2x drivetrains.
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Adjust B-tension and confirm chain length for optimal performance and shifting precision.
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Maintain regular chain cleaning and lubrication for best efficiency and bearing longevity.
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.
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).
