Enduro's Directline pulleys refine its top-tier XD-15 design with larger caps that help minimise bearing movement and contamination. This 11-tooth upper and 13-tooth lower set is designed as an upgrade for most 11 and 12-speed Shimano GRX 2x rear derailleurs.

Highlights

• Directline design with larger caps to help minimise bearing movement and contamination
• XD-15 ceramic hybrid bearings: cryogenically treated nitrogen steel races with Grade 5 silicon nitride balls
• Deep-groove races and a 90% fill of Kluber NBU 52 grease that resists washout
• CN (tight clearance) bearing in the upper pulley for shift accuracy, C4 (loose clearance) in the lower for chainline movement
• 500 AF Delrin with Teflon: less drag than aluminium or titanium pulleys
• 11-tooth upper and 13-tooth lower pulleys with 5mm bolt holes
• Precision manufactured in the USA

XD-15 ceramic hybrid bearings

Exclusive to Enduro, XD-15 bearings combine corrosion-proof, cryogenically treated nitrogen steel races with Grade 5 silicon nitride ceramic balls. Deep-groove raceways take the largest possible balls for more contact area, and a 90% fill of Kluber NBU 52 grease is engineered to cling to the balls and keep being drawn back into the ball path, so it resists washout and runs smoother with time.

Machined 500 AF Delrin

500 AF Delrin has high tensile strength and rigidity, natural lubricity and strong resistance to moisture, caustic chemicals and UV, so the pulleys stay durable, rigid and smooth. Its Teflon content cuts friction where the pulley meets the chain, giving significantly less drag than aluminium or titanium pulleys. Enduro makes its pulleys at three levels (ceramic hybrid, black-oxide Zero ceramic and XD-15 ceramic hybrid at the top), all precision manufactured in the USA.

Compatibility & fit

Designed as an upgrade for most 11 and 12-speed Shimano GRX 2x rear derailleurs. Enduro lists the RD-RX810, RD-RX815, RD-RX820 and RD-RX825. For the 12-speed GRX RD-RX822 1x derailleur, Enduro specifies BKCJ-0361 instead. Check your derailleur model, speed and pulley bolt sizes before ordering. Our Marrickville workshop can fit the pulleys and check your derailleur adjustment while it's apart. Fitting is a separate workshop service and isn't included in the price.