The Shimano RT-CL800 is an Ice Technologies Freeza rotor built to shed heat fast and keep braking consistent on long, steep descents. This 203mm version uses a Centerlock fitting with an internal-serration lockring and carries a built-in magnet that works with e-bike speed sensors, so it suits the front wheel of a road, gravel or e-bike build that needs both serious stopping power and accurate speed reading.

Highlights

• Ice Technologies Freeza three-layer construction draws heat away from the braking surface for stable, fade-resistant performance
• Built-in magnet for e-bike speed sensors, integrated into the rotor carrier
• 203mm diameter for maximum braking power, ideal for heavier loads and steep terrain
• Centerlock mounting with an internal-serration lockring for fast, secure installation
• Stainless steel braking surfaces over an aluminium core with exposed cooling fins
• Ultegra/GRX-grade rotor, also cross-compatible with Shimano XT and other Centerlock systems

Ice Technologies Freeza cooling

The rotor sandwiches an aluminium layer between two stainless steel braking surfaces, with the aluminium extended into exposed radiator fins. This pulls heat out of the braking zone and lowers operating temperatures, which helps maintain braking force, extends pad life and reduces noise on sustained descents.

Built-in e-bike speed sensor magnet

Unlike the standard RT-CL800, this LJ variant has a magnet built into the rotor. It triggers the wheel-speed sensor on compatible e-bike systems, removing the need for a separate spoke magnet and giving a clean, accurate speed reading.

Compatibility & fit

Fits Centerlock hubs only. Works with Shimano 9/10mm quick-release and 12mm thru-axle hubs. The 203mm size requires a calliper and adaptor rated for a 203mm rotor. Designed for Shimano Ultegra and GRX, and compatible with XT-level and other Shimano Centerlock brake systems. The integrated magnet is intended for Shimano-compatible e-bike speed sensors; confirm your e-bike system supports rotor-magnet speed sensing. Lockring is included.