Shimano's flagship RT-CL900 is the rotor that sits behind Dura-Ace and XTR brakes, built to shrug off heat on long descents and stay quiet under hard, repeated braking. This 140mm version ships with the external serration lockring, so it suits Center Lock hubs running larger thru-axles.

Highlights

• Ice Technologies Freeza construction pulls heat out of the braking surface for more consistent power and less fade on steep descents
• Two-piece build pairs a lightweight aluminium core with stainless steel braking tracks to cut weight without losing durability
• Heat-dissipating paint and a refined arm shape help keep braking quiet and reduce rotor rub
• Works with both resin and metal brake pads, so you can tune feel and longevity to your riding
• External serration lockring suits Center Lock hubs with larger thru-axles, where an internal-serration lockring tool will not fit

Heat control that holds up

The Freeza design sandwiches an aluminium core between stainless steel braking surfaces and adds heat-dissipating paint, drawing warmth away from the pad contact area. The result is steadier braking power, longer pad life and less of the squeal that comes from an overheated, distorted rotor.

Light, stiff and quiet

A three-dimensional aluminium carrier keeps weight down to around 97g while resisting heat distortion. Holding its shape under load means less rubbing noise and a cleaner, more predictable feel at the lever.

External serration lockring explained

Center Lock lockrings come in two styles. Internal serration rings are tightened with a cassette-style tool passed through the axle and suit 12mm thru-axles and quick-release hubs. This external serration ring has its teeth on the outside and a larger centre, so it clears thicker thru-axles (such as 15mm) where the internal tool would foul the axle. It is tightened with an external Center Lock lockring tool (TL-LR15 type), not a cassette lockring tool.

Compatibility & fit

140mm rotor for Center Lock hubs. Supplied with an external serration lockring for hubs with larger thru-axles where an internal-serration ring will not fit. Compatible with both resin and metal disc brake pads. Shared across the Dura-Ace R9200 and XTR M9100 families and suited to any compatible Shimano hydraulic disc brake calliper running 140mm rotors. Always pair the rotor size with the calliper and mount that your brakes are specified for.