R10 000 upgrade for your Shimano gears

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The hollow lower pulley wheel, is embedded to the derailleur cage’s structure, instead of centre-bolted.
The hollow lower pulley wheel, is embedded to the derailleur cage’s structure, instead of centre-bolted.
  • Engineers at AbsoluteBLACK know all about customizing drivetrains
  • The company is a global leader in oval shaped chainrings
  • But its latest product innovation, is a futuristic rear derailleur cage, that whisper smooth

AbsoluteBLACK is a component company, that is obsessed with the tiniest of gains.

Despite being based in England, the brand’s roots are Polish, where the founder, Marcin Golec, is from.

Exhaustive data analysis and computer-aided design are what AbsoluteBLACK does best. Although mostly known for oval chainrings, AbsoluteBLACK has expanded into ridiculously expensive low-friction chain lubricants.

For AbsoluteBLACK, everything is an effort to reduce friction and optimize power transfer. The latest product that promises to help you lose fewer watts of pedalling effort, is the HollowCage.

The HollowCage works with Shimano Dura-Ace R9100/R9150 & Ultegra R8000/R8050 components (Photo: AbsoluteBLACK)

Making your drivetrain more aero

It might look a touch too big, but that’s the secret. Engineers have realised, that oversized pulley wheels can turn more efficiently, reducing slack in the chain of a bicycle drivetrain.

AbsoluteBLACK has taken this concept to the extreme with its HollowCage design. It features a monocoque structure and massive lower pulley wheel, with a noteworthy hollow centre (hence, the name).

What is the idea behind it? Lightness. As a start. The HollowCage weighs only 71g, which is much lighter than a conventional road bike rear derailleur from SRAM, Shimano or Campagnolo.

Beyond saving weight, it also features a dimpled finish, similar to that of a golf ball. The reason? Aerodynamics. Dimpled surfaces, on a specific shape, create less aerodynamic drag than a perfectly flat surface and AbsoluteBlack’s industrial designers have integrated this idea, with the HollowCage.

bicycle gears
The HollowCage design is a study in functional minimalism (Photo: AbsoluteBLACK)

So quiet, other riders won't hear you coming 

Unlike traditional derailer cages, which have a twin-spar structure, the HollowCage is single-sided.

How much greater is its efficiency than a conventional premium rear derailleur cage? AbsoluteBLACK is not putting an exact value to that, in watts. What they will confirm, is that the HollowCage derailleur cage and pulley wheels, run two decibels quieter, compared to any rival component.

Less noise does equal less mechanical drag. But the cost is extreme, for this new bit of AbsoluteBLACK magic. The HollowCage derailleur cage retails for R10 000. 

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