The Shimano SLX SM-RT66 is a dependable 6-bolt disc brake rotor built for consistent, fade-resistant stopping. In the largest 203mm size it gives you the extra swept area and thermal mass that heavier riders and long, sustained descents demand, while staying compatible with both resin and metal pads so you can run the compound that suits your conditions.

Highlights

• Big 203mm rotor for stronger braking and better heat management on long descents
• Compatible with both resin and metal brake pads, so you can switch compounds seasonally
• Anti-loosen tightening plate keeps the six bolts secure under vibration and braking load
• One-piece stainless steel construction for durable, reliable performance
• Standard 6-bolt fitment works across a wide range of Shimano MTB and road hydraulic calipers

More power when you need it

The 203mm diameter is the largest in the SM-RT66 range. The extra rotor surface gives your brakes more leverage and more material to absorb and shed heat, which means more confident, repeatable stops on steep terrain and for heavier loads.

Run the pads you prefer

Unlike resin-only rotors, the SM-RT66 is rated for both resin and metal (sintered) pads. Run quieter resin pads for dry trails, or switch to metal for wet and muddy conditions where you want more bite and longer pad life.

Secure, fuss-free fitting

The anti-loosen tightening plate locks the six rotor bolts in place so they resist backing out under repeated braking, for a secure install that stays put.

Compatibility & fit

Standard 6-bolt (ISO) rotor mount, fits any 6-bolt disc hub. Standard-thickness steel rotor rated for both resin and metal pad compounds. Compatible with Shimano hydraulic disc brake calipers including MTB models such as BR-M6220, BR-M8220 and BR-M9220, and road/gravel models such as BR-R7170 and BR-R8170. Confirm your frame, fork and adaptor are rated for a 203mm rotor before fitting.