OneUp RADr rear derailleur cage review

Novel solution to crawler cog blues

Our rating 
3.5 out of 5 star rating 3.5
USD $55.00
OneUp RADr rear derailleur cage

Our review

A worthwhile upgrade if you’re desperate for a 42t sprocket but can’t afford to go 11-speed
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Adding a 42-tooth ‘crawler cog’ to your 1×10 drivetrain may make the climbs easier but it also leaves a big gap between sprockets that can cause shifting problems, or at least require painstaking set-up. Enter OneUp with the RADr cage. Designed to replace both cages on your Shimano Shadow Plus rear derailleur, it moves the top jockey wheel backwards for better shifting between the big sprockets.


It’s straightforward to fit, though you need to disassemble your derailleur – and a seized stop screw on our SLX unit meant we had to get the mole grips out. Shifting to and from the 42t sprocket is noticeably improved and seems just as slick as usual elsewhere. We can’t comment on durability yet but the 7075-T6 alloy cage has a low profile to help keep it out of the way of rocks.

Add in the cost of a OneUp 42t sprocket (US$90) and it’s still more affordable than the cheapest 1×11 option – a Shimano XTR cassette, derailleur, shifter and chain. But if you don’t need such a wide range of gears, a 40t cog offers many of the benefits with no need for a new cage.


The RADr cage ships worldwide from the US – check for more info

Product Specifications


Name RADr rear derailleur cage (15)
Brand OneUp Components

Material 7075 T6 Aluminium