Compatible with Shimano XT/XTR or GRX/RX derailleurs, the CeramicSpeed Oversized Pulley Wheel X Systems (OSPW X) brings all the watt-savings which had previously been reserved for road rear derailleurs to off-road riders with Shimano drivetrains.
Already race-proven, with a win at the U23 cyclocross world championships, the OSPW X system for Shimano GRX 810/815 and Ultegra RX 800/805 was specially designed for gravel and ‘cross riding. The oversize pulley wheels inherit technology tested on the pavé of Paris-Roubaix and the white gravel of Strade Bianche, and they have been designed for a double chainring configuration.
The upper pulley wheel has 13 teeth, while the lower has 19. Larger pulley wheels mean a wider chain-wrap diameter, resulting in less friction. The OSPW X System is 11-speed compatible with cassettes with a range of 11 teeth to 36 teeth.
CeramicSpeed notes that there are many variables when calculating watt savings, but as a general rule, a saving of 5 watts means you could ride 0.5sec/km faster on the road. With all other factors being equal, a rider equipped with CeramicSpeed OSPW System could ride 100km 24 seconds faster compared with a standard rear derailleur.
For those who are running XT/XTR drivetrains with a 1×12 setup, the OSPW X derailleur upgrade incorporates a proprietary, symmetrical 14-tooth upper and 18-tooth lower pulley profile. This configuration was designed for 12-speed cassettes with a range of 10 teeth to 51 teeth, and comes with two tension springs so you can customize your how your derailleur will behave depending on the terrain you’re riding.
SRAM users haven’t been excluded: CeramicSpeed already offers oversized pulleys for Eagle mechanical, and Eagle AXS derailleurs.
The new OSPW X is available with either standard bearings ($549), or coated bearings ($649) for even greater friction reduction.