OneUp RAD Cage Hacks Shimano Rear Derailleurs to Better Fit Oversized Cogs
OneUp Components has introduced a few firsts in the oversized cog game, namely the 16T replacement cog. Now, the RAD Cage boosts derailleur performance at the top end of the cassette without having to reverse or extend your B-Screw.
Made for modern, clutch equipped 10-speed Shimano Deore, SLX, XT or XTR medium cage rear derailleurs, it repositions the upper pulley to improve tooth and chain clearance over 40 and 42 tooth cogs. I installed it on my Niner RIP 9 RDO, which was already running their 40T and 16T cogs. When originally setup with those two parts, I had to bury the B-Screw all the way, which just barely left enough room between the pulley and the largest cog. There was no way OneUp’s (or anyone else’s) 42T cog was fitting in there without more drastic measures. Until the RAD Cage, anyway…
The RAD Cage kit includes the outer cage and a new mounting screw since you’ll use the original to bolt the pulley to its new location.
The big hole in the middle is the original location of the pulley. On the RAD Cage, it’s simply where you’re reattaching the cage to the derailleur. The pulley gets bolted to the smaller threaded hole just behind it (not the one showing silver threads in this pic, the other one that’s showing green threads).
Size is virtually identical, and marks are clearly etched on the outside face so you know where to reinstall the clutch’s tension spring. XTR uses a different hole than SLX and XT.
Before and after shows the pulley slightly higher and rearward. It’s not just improving the position on the big cog, it allows for a bit more chain wrap on the smaller cogs, too.
The only downside? It adds about 11g.
Well, that, and good luck getting this little C-clip back in place. I haven’t had enough trail time on it yet to see if the bolt comes loose, so look for the long term report in the future. Shimano’s known for doubling up on security measures for bolts and parts elsewhere on the bike, so hopefully this is just redundant.
The installation requires disassembly of the clutch mechanism and removal of the cage. It took me about 20 minutes including photography and running back and forth to computer to watch OneUp’s install video. So, pretty quick and straight forward with standard tools most folks already own.
The pic above shows how much the pulley is offset from center line, and this diagram illustrates it in action:
On the small cogs, the pulley sits up a bit higher, wrapping the chain around the cog just a bit more. As you run up the cassette, it shifts downward to create more space.
On the 40T cog, it allowed me to back out the B-Screw about 1/8th an inch, which improved chain wrap on many of the cogs.
OneUp sent a 42T cog that I’ll be swapping in to test clearance, but the pic above shows how much room is gained by burying the B-Screw. Which is the secondary benefit of the RAD Cage, you don’t need to flip your B-Screw or get a longer one and lessen chain wrap for the rest of the cogs. More chain wrap means better performance and longer cassette life.
Trail time coming up soon, stay tuned. In the meantime, the RAD Cage is available now for just $35. Also available in Black.
20 Second Promo Video: