Hollowcage® Shimano 9250 Carbon Ceramic Oversized derailleur pulley cage

Does it bother you when you ride in a really quiet scenery but you can still hear your bike’s chain engaging the pulleys? This familiar clunking noise has been accompanying us on every ride for decades. It’s time for a change.

Common polymer pulleys are fairly loud, this has always been a norm. Aluminium pulleys are even worse as the material radiates the sound more than any polymer, making them louder. We are introducing a completely new generation of pulleys, which are able to reduce the sound level by 5-7dB when compared to stock Dura Ace pulleys. This corresponds to roughly 40% of the noise reduction. Practically speaking, the cage becomes very silent.

We use a patent pending solution, our special xring rubber suspended bands, that dampen the chain impact on the guide pulley teeth, therefore eliminating the engagement noise, which is the single biggest contributor to overall drivetrain noise. From now on, your ride is going to be more silent than it used to be and you will hear sounds that you haven’t noticed before. It's the new era of derailleur cages

*It is super silent (over 5dB noise reduction vs stock).
*The shifting is as good as with the original Dura Ace cage.
*One of the lightest oversized cages on the market.
*First mono plate construction of its kind.

Our bearings are full ceramic. In technical nomenclature, it is a bearing with inner and outer race as well as balls, made of ceramic material. The seals and the cage however, are made of polymer. Other common types of bearings are steel bearings and hybrid bearings. The latter is often mistakenly called "ceramic" bearing but only the balls are ceramic, races are still made of steel. Hence there is a term "full ceramic" indicating that not only the balls are made of ceramic but both races too. Our bearing races are made out of 100% Zirconia Oxide ceramic and balls are made of Silicon Nitride ceramic. The cage and seals are of course made of low friction polymer.

Please refer to the video instruction below. For Sub Compact (<34/50t) and Compact (34/50t) chainring combinations, you can use the lowest spring tension setting (First hole from left). However, If you ride on roads with potholes, cobbles, etc. it is recommended to set the HOLLOWcage to the high spring tension (First hole from right). If you have 52t chainring or bigger, use high spring tension setting.
For service / maintenance instructions please refer to our FAQ page.

In the video below you will also find how to determine the correct chain length for your HOLLOWcage. Following this tutorial is crucial for the proper functioning of the drivetrain.

We offer 4 year warranty on bearings* (for more information please refer to our FAQ page)