CERAMICSPEED OVERSIZED CERAMIC PULLEY WHEEL SYSTEM - LIMITED GIRO D'ITALIA - SHIMANO DURA-ACE 9100

With the advent Shimano Dura-Ace 9100 mechanical and 9150 electronic, the most common rear derailleurs used by pros, it was essential that CeramicSpeed develop a new Oversized Ceramic Pulley Wheel System (OSPWS) for the derailleur.

As you can imagine, CeramicSpeed has done everything possible to reduce frictional drag to as close to zero as is possible. They started with pulley size. They determined that the best solution was a 13-tooth upper pulley and a 19-tooth lower. This way, you can install cassettes up to 32-teeth on your rear wheel and still take advantage of these pulleys.

The result is a 30% drop in mechanical friction and three to five times longer lifetime than the standard Shimano pulley setup. The pulleys are fabricated out of aluminum and have spokes supporting the teeth rather than solid aluminum, which both reduces weight and reduces muck buildup in dirty conditions.

But this isn’t merely about reducing friction. It’s about improving performance everywhere possible. The cage is a carbon-reinforced plastic to both provide the rigidity shifting requires and the lowest possible weight for the design. The spring tension is adjustable, so you can get the wrap you want. The bolts CeramicSpeed includes with the pulleys are titanium.

The heart of the system are CeramicSpeed’s standard hybrid ceramic bearing. CeramicSpeed utilizes Grade 3 Silicon Nitride balls that possess the best possible surface finish and roundness. In testing, the balls are 400% smoother, 128% harder, and 58% lighter than standard steel balls found in most bike components. They’re more than 100% smoother and 15% harder than standard ceramic balls. The balls are installed into hardened steel races in dust-free clean rooms and then checked again before assembly is complete.

There are two options with this kit, uncoated, and coated. Uncoated is what they base most of their test data off of, so it’s the CeramicSpeed standard. Coated is even smoother and longer lasting, as it’s a metallic layer on top of the races, three microns thick and 75% harder than hardened steel races.

As you can imagine, installing this system is a bit more involved than replacing pulleys. Rest-assured, it is more straightforward than you fear. You’ll need a set of Allen keys. You can perform the installation on the bike or off, though on makes the installation a bit easier. You’ll probably also need a few more links in your chain, so starting with a new chain might be the easiest way to begin.  They kit also comes with their own Pulley Wheel Oil.

The CeramicSpeed OSPWS for Shimano 9100/9150 rear derailleurs takes Shimano’s top-of-the-line changer that much higher.