The key feature of the OneUp RAD (Radial Appositioned Derailleur) cage is that we’ve moved the upper pulley wheel rearward of the cage pivot to optimize the derailleur for larger sprockets. Now as the derailleur moves into larger sprockets the top pulley wheel automatically moves away to adjust the chain gap, no longer relying on just B-Screw.
The RAD cage is a 1x10 11-40/42 specific product only for Med cage derailleurs . Long cage (SGS) derailleurs are only needed for 2x drivetrains. Shorter derailleurs are preferred for 1x10 systems as they’re lower profile so less vulnerable to damage on the trail and they allow you to run a shorter chain which improves chain retention.
SGS models of the derailleurs above as well as Saint (RD-M820) and Zee (RD-M640) can be converted to use a RAD cage. This requires the purchase of a GS inner plate from one of several online retailers or your local shop. The part numbers are - Y5XC09000 (XTR), Y5XC09100 (XT, SLX) or Y50H09000 (Deore).
NOTE: Any of the three part numbers above are functionally interchangeable. There may however be material or small aesthetic differences.
NOTE: Saint (RD-M820) and Zee (RD-M640) use the XT spring mounting hole on the RAD cage.