Ceramicspeed OSPW RS 5-Spoke for Shimano Dura-Ace R9250/Ultegra R8150 Derailleur Pulley (Black)

This 5-Spoke OSPW RS is CeramicSpeed's pulley system sized for Shimano's current 12-speed Di2 flagship and second-tier groupsets - Dura-Ace R9250 and Ultegra R8150. The idea is the same across the whole OSPW range: a larger pulley diameter reduces how sharply the chain bends as it passes through the rear derailleur, which lowers friction and, over a long ride, adds up to a measurable efficiency gain.

It uses hybrid ceramic bearings in a carbon cage, with pulleys sized to handle cassettes up to 34 teeth, so it covers both compact and wide-range Di2 builds. Because it's matched to R9250/R8150 specifically, fitment and derailleur geometry are accounted for rather than left to a universal-fit design.

This suits a rider who's already on Shimano's newest 12-speed Di2 groupset and is looking at componentry upgrades rather than new bike purchases - the kind of upgrade that shows up as a small but real gain rather than a visible change to the bike.

Why You'll Like It

Matched to your exact groupset
Sized and geometrically matched to Dura-Ace R9250 and Ultegra R8150 Di2, rather than being a generic aftermarket cage that may not sit right in the derailleur.

Hybrid ceramic bearings
Ceramic bearing elements reduce rolling resistance at the pulley wheels compared to the stock steel bearings Shimano ships with.

Wide cassette compatibility
Rated for cassettes up to 34T, so it works whether you're running a tight road cluster or a wider-range setup for climbing.

Carbon cage construction
Keeps the added pulley diameter from adding meaningful weight to the rear derailleur.

Who Is It For?

This is for a rider already running Dura-Ace R9250 or Ultegra R8150 who's chasing the kind of marginal gains that matter in racing or serious training, rather than someone shopping for their first upgrade. It's a drivetrain-level change, so it suits someone who already has their bike fit and gearing sorted.

For Indian riders doing longer road rides or racing, the reduced drivetrain friction is the kind of upgrade that compounds over distance - more noticeable on a 100km+ ride than a short loop. It's less relevant for someone who rides mostly short, stop-start urban commutes.

Good to Know

Have your mechanic recheck derailleur limit screws and B-tension after fitting, since the larger pulley cage changes the derailleur's resting geometry slightly from stock.

Keep bearings clean of road grime, particularly after wet rides, to get the full benefit of the reduced-friction design over time.

Check your cassette's largest sprocket against the 34T limit before fitting if you run a wide-range Di2 cassette.

Technical Specifications

• Material: Stainless steel and hybrid ceramic bearings, carbon cage
• Bearings: Hybrid ceramic
• Cassette Teeth Max: 34T
• Compatibility: Shimano Dura-Ace R9250 and Ultegra R8150 (12-speed Di2)
• Speed: 12 Speed

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