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Absoluteblack Hollowcage: new 'silent', monoplate oversized pulley cage

20 Jul 2021

'Revolutionary' new rear derailleur cage is claimed to save watts and weight while reducing noise by 60%

Absoluteblack has released the Hollowcage, a new oversized derailleur pulley cage that the brand says is 'the dawn of a new era for rear derailleurs'.

The British manufacturer, best known for its oval chainrings and Graphenlube wax lubricant, claims that while rear derailleur cages haven't changed for almost 70 years, the Hollowcage's carbon mono-plate designed 'changes everything' with its oversized, full ceramic bearings and 'the most advanced silencing pulleys ever created'.

Silence is carbon

The Hollowcage features what Absoluteblack is calling the Silent Xring Pulley, which uses rubber suspended bands that dampen the chain's impact on the pulley teeth, minimising the sound from engagement.

As a result, the brand claims that the noise level is reduced by 12-14dB, around 60%, compared to standard Shimano Dura-Ace pulleys.

Stiffness has also been refined, with a flexible cage and a stiffer guide pulley. Absoluteblack says having a flexible cage allows for better alignment with the higher gears and reduces friction, thus saving watts, as the pulley isn't fighting the chain.

Alignment is helped further by removing a part of the cage and making a mono-plate cage that is more adaptable to different angles.

To increase the stiffness of the guide pulley, the Hollowcage uses oversized, full ceramic bearings, which are said to bring superior shifting to other pulley cage systems. Absoluteblack explains: 'Most oversized pulley cage systems use very small bearings, with a lot of lateral play at the teeth, which in turn provide poor, sloppy shifting.'

For further shifting improvement, the Hollowcage's upper pulley has tall teeth that help to boost the precision of the shifting when compared to the shallow teeth of its competitors.

Watt's in it for me?

Aside from sonic and textural improvements, Absoluteblack says the Hollowcage is actually more aerodynamic than both the Dura-Ace cage and the 'market leading' competitor, though it admits the differences are small enough that there aren't any 'meaningful watt losses' between the options.

It says the biggest saving comes from the spring tension and the cage's adaptibility to the chainline, which, thanks to the tall teeth and mono-plate design, gives the Hollowcage an advantage on the rest of the market.

It's apparently also one of the lightest oversized cages you can buy, weighing in at 71g.

Options and price

Whle the Absoluteblack Hollowcage isn't cheap, setting you back £519, it is available in rainbow, titanium, red and gold as well as the slick black.

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