CeramicSpeed OSPW RS Alpha Derailleur Pulley System for Shimano R9250 / R8150 - black/universal

CeramicSpeed OSPW RS Alpha Derailleur Pulley System for Shimano R9250 / R8150

Item number: 94228


Road, Triathlon & Time Trial
Cassette Teeth (max.):
Shimano Dura-Ace Di2 RD-R9250, Ultegra Di2 RD-R8150

Technical Information:

Derailleur Pulleys:
13 tooth (upper derailleur pulley), 19 tooth (lower derailleur pulley)
Outer Cage Material:
Inner Cage Material:
Other Materials:
aluminium, composite


  • oversize derailleur pulley system with ceramic bearings for Shimano Dura-Ace Di2 RD-R9250 and Ultegra Di2 RD-R8150
  • Further Drive technology to improve and extend performance in road use
  • high-performance bearings with very hard, above-average supple and resilient ceramic balls made of grade-3 silicon nitride (best achievable grade for ceramic bearings)
  • Alpha Disc tension pulley for greater rigidity, durability, safety and reduced noise levels
  • compatible with 10-34 12-speed cassettes
  • handmade in Denmark

For hazard warnings, safety and application information, please see CeramicSpeed Oil for Derailleur Pulleys.


Ceramic Bearings by CeramicSpeed
CeramicSpeed ceramic balls are rounder, harder, smoother, lighter and more resilient than steel balls and ceramic balls from other manufacturers. CeramicSpeed ceramic bearings therefore last 3 to 5 times longer than other bearings on the market. All CeramicSpeed bearings are handmade in Denmark under clean room conditions and subjected to a strict four-stage inspection process. Among other things, the size of the ceramic balls is checked down to the thousandth of a millimetre. Tests are then carried out in the laboratory or preferably by professionals in training and competition. CeramicSpeed bearings guarantee the lowest possible friction, optimised power transfer and maximum durability and also help you save watts and reach the finish line faster. It's not about seconds, it's about minutes!

The Oversized Pulley Wheel System (OSPW system) is a breakthrough innovation from CeramicSpeed, developed in collaboration with world-class triathletes. This unique system is known for 40 - 60% less friction compared to standard derailleur pulleys and allows power savings of at least 1.6 and up to 2.4 watts. The OSPW system features the unique CeramicSpeed bearings, aluminium derailleur pulleys and a polyamide-carbon cage, making it 3 to 5 times more durable than standard systems on the market.

Further Drive
CeramicSpeed derailleur pulley systems with Further Drive technology are designed to make your drivetrain more durable and less sensitive to wear so that it works efficiently over a long period of time. This means you can still fully rely on it at the end of the race or late in the season. Further Drive includes a completely revised cage structure of the OSPW system with greater material thickness, but without unnecessary weight. ADR and ALPHA Disc are also central components of the Further Drive concept.

ALPHA Disc is a two-part construction that affects the lower pulley, the tension pulley. The teeth have a Narrow-Wide profile for better chain retention and are made of a highly wear-resistant, noise-reducing composite material. They sit on a solid aluminium disc, which prevents foreign objects such as branches from getting caught. At the same time, the disc increases the strength and rigidity of the derailleur pulley. The first ALPHA discs were tested at the Cyclocross World Cup. The technology was then used regularly by the Tormans CX Team sponsored by CeramicSpeed and was able to impress in the most difficult conditions.

Note from the manufacturer:

Before transporting the bicycle in a travel bag, the rear derailleur should be completely disassembled, otherwise the OSPW system could be damaged.

Manufacturer Numbers:

team edition-black:


  • 1 x CeramicSpeed OSPW RS Alpha derailleur pulley system for Shimano R9250 / R8150
  • 1 x CeramicSpeed oil, 15 ml dropper bottle


  • black/universal: 85 g
  • 100 day return period
  • Online since 1998
  • Trusted Shop 4.85 / 5.00


  • black/universal, in stock
  • team edition-black/universal, in stock – delivery time 10 workdays

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