Ceramicspeed OSPW RS Alpha for Shimano Dura-Ace R9250/Ultegra R8150 Derailleur Pulley (Black)

The Alpha RS sits above the standard OSPW RS line as CeramicSpeed's higher-spec oversized pulley wheel system, built for Shimano's Dura-Ace R9250 and Ultegra R8150 12-speed Di2 groupsets. It carries CeramicSpeed's signature team-logo cage finish, the same cosmetic treatment used on their WorldTour-level componentry.

Inside, it runs 15-tooth guide and 19-tooth tension pulleys on hybrid ceramic bearings in a carbon cage, rated for cassettes up to 34 teeth across the full 12-speed Di2 range. The box includes a Dura-Ace R9250-specific derailleur spacer and CeramicSpeed's own pulley bearing oil for ongoing maintenance - details that place this at the premium end of the OSPW lineup rather than the entry point.

This is the pick for a rider who wants CeramicSpeed's flagship pulley system rather than its standard offering - someone for whom the Alpha's bearing quality and finish justify the step up from the 5-Spoke version.

Why You'll Like It

CeramicSpeed's flagship pulley tier
The Alpha sits above the standard OSPW RS range, with the brand's best hybrid ceramic bearings and a team-logo carbon cage finish.

Matched to Dura-Ace/Ultegra 12-speed Di2
Sized specifically for R9250 and R8150, including a dedicated Dura-Ace R9250 derailleur spacer included in the box.

Comes with bearing oil
CeramicSpeed includes their own pulley bearing oil in the box, so you're set up for ongoing maintenance from day one rather than sourcing it separately.

Wide gearing range covered
Rated up to a 34T cassette, so it suits both tighter road gearing and wider-range climbing setups on the same groupset.

Who Is It For?

This is for the serious racer or dedicated enthusiast already on Dura-Ace R9250 or Ultegra R8150 who wants CeramicSpeed's best pulley system rather than its mid-tier option - someone for whom marginal drivetrain gains and premium componentry both matter.

It makes the most sense for riders doing structured training, racing, or long weekend rides in India where drivetrain efficiency compounds over distance, rather than short commuter use where the gain is barely noticeable.

Good to Know

Use the included bearing oil on a regular maintenance schedule to keep the ceramic bearings running at their best - don't substitute a generic chain lube for pulley bearing servicing.

Fit the included Dura-Ace R9250 derailleur spacer as directed; skipping it can affect derailleur alignment on this specific groupset.

Have a mechanic check B-tension and limit screws after installation, as with any oversized pulley cage swap.

Technical Specifications

• Material: Stainless steel and hybrid ceramic bearings, carbon cage
• Bearings: Hybrid ceramic
• Pulley Teeth: 15T (guide) / 19T (tension)
• Weight: 102g
• Cassette Teeth Max: 34T
• Compatibility: Shimano Dura-Ace R9250 and Ultegra R8150 (12-speed Di2)
• Speed: 12 Speed
• In The Box: CeramicSpeed Alpha RS OSPW, Dura-Ace R9250 derailleur spacer, pulley bearing oil

Additional Information

• Country of Origin: China
• Imported By: Ensign Sports, 502, Hill Glade, Opp. HDFC Bank Pali Road, Bandra, Mumbai - 400050, Maharashtra, India.
• Net Quantity: 1N