Just In – OneOneUp Components Shimano RAD derailleur cage

by Brian Mullin on August 15, 2014

The RAD Cage from OneUp Components replaces the outer cage on the Shimano GS clutch rear derailleurs and is optimized for 11-42 and 11-40 10-speed wide-range cassette systems. The RAD (Radial Appositioned Derailleur) cage dramatically improves shifting performance, chain wrap and extends cassette life when used with an extended cassette setup.

The gist of the extended system is that an 11-36T 10-speed cassette is upgraded to 11-40 or 11-42 setup utilizing the OneUp Components 40T or 42T sprockets, and it’s a low-cost alternative to making a pseudo-SRAM 1×11 10-42T drivetrain. The creation of the wide-range cassette is simple and only requires swapping out a couple of cogs from the 11-36T cluster; remove the 15T and 17T, insert the OneUp 16T and add their 40T or 42T sprocket.

Here was my initial review on the system: Just In – OneUp Components 42T Sprocket

Ten speed derailleurs are designed for 11-34 and 11-36 cassettes, and when used with the 40T and 42T sized sprockets, the b-tension screw must be set to its maximum outward limit to make the derailleurs upper pulley clear the large cog. Unfortunately, this alteration means the pulley is farther away than normal in the smaller cogs, creating slower and less responsive shifting, and Shimano’s derailleur architecture exacerbates this issue.

The RAD cage design has moved the upper pulley rearward of the cage pivot to optimize the derailleur for the larger 40T and 42T sprockets. This alteration keeps the top pulley above the cage
pivot and closer to cassette in the smallest cogs while it automatically moves away to adjust the chain gap in the larger ones. The pulley repositioning allows the b-tension screw to be set to a more normal distance, and the synergy of all these changes creates crisper shifting and more chain wrap.

The RAD cage is CNC’d from 7075-T6 Aluminum, weighs 26 grams, comes in Green and Black and retails for $35. It’s meant for 1×10 11-40/42 specific cassettes, and Shimano medium cage derailleurs, including the Deore, SLX, XT and XTR models.

RAD Benefits

  • Dramatically improves shifting performance for Shimano derailleurs
  • Tuning your derailleur to achieve perfect shifting with an 11-42 is now much easier
  • Requires stock B-Screw length and adjustment (No more removing washers or reversing B-Screws)
  • Improves chain wrap and extends cassette life
  • Installs in under 15 minutes – checkout the install video for full details

Initial Impressions

My test setup on my Ibis Mojo HDR:

  • XTR cassette with OneUP 16T and 40T cogs
  • SLX Shadow Plus derailleur
  • SRAM 1051 chain
  • X0 crank with 28T North Shore Billet direct mount chainring

It was fairly simple to install the RAD cage on my Shimano SLX derailleur, and I even did it with the shifter cable still attached. It might facilitate a quicker and easier installation without the cable getting in the way, but I didn’t feel like re-doing the cable setup. Once I had installed the RAD cage, I loosened the b-tension screw to just above its halfway point, which was slightly higher than its normal positioning for the original 11-36 gearing. On the bike stand, the shifting seemed much better than before, and it rolled to the large cogs smoothly and I didn’t notice any of the previously encountered clunky transitions in the smaller cogs.

I lubed the chain and took the new setup out for its maiden voyage. I was thoroughly surprised at how well it performed, and even with purposeful poor shifting techniques, it kept great composure. After many days and miles on the bike, the RAD cage has significantly improved shifting performance, and given crisper, smoother and faster transitions in any gear, and it was especially noticeable down in the previously problematic lower cogs. In direct comparison to the SRAM 1×11 system, it lacked the exacting precision and smoothness of that drivetrain, but it wasn’t that significant in the grand scheme of things.

The RAD cage is a great addition to their 16T and 40/42T extended system, and it significantly improves shifting. The design repositions the upper pulley with the cage pivot, and the synergy of a looser b-tension, closer functional pulley positioning and chain wrap, produces greater performance throughout the gearing spectrum, from the smallest to the largest cog.


  • Low-cost
  • Improves shifting over standard 11/40 or 11-42 system – especially lowest cog
  • Better chain wrap
  • Looser b-tension


  • No SRAM version
  • No quite SRAM 1×11 precision – but very close

{ 1 comment… read it below or add one }

Lee Liu August 18, 2014 at 11:22 pm

SRAM does not need it…since it already has an offset pulley.


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