SHIMANO's GRX Di2 12-speed rear derailleur features a built-in wireless connectivity unit and charging port, ensuring fast and reliable shifting for mixed-terrain riding and easy recharging. Integrated SHADOW RD+ technology prevents chain slap and ensures precise shifting even on rough terrain. Thanks to built-in ON/OFF switch, wheel removal is easy too. The RD-RX825 is compatible with 11-34T and 11-36T 12-speed cassettes and supports Full or Semi-Synchronized shift modes, enhancing rider customization.
Compact design with integrated wireless unit, charging port, and switch
Fast and reliable shifting on rough terrain
Adjustable chain stabilizer prevents chain slap
Gravel-tuned clutch tension
Switch stabilizer ON/OFF to match terrain: ON for gravel, OFF for smooth roads
LED status indicator
Battery indicator, pairing, adjust mode, etc.
Attributes
Max Front Difference
17T
Maximum Cog
36T
Minimum Cog
11T
Primary Color
Black
Cage
GS
RD Capacity
40T
RD Spring Type
Shadow Plus
Speed
12
Mount
Standard
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Specs
Size
Metric
Imperial
This is a size chart.
Geo
Metric
Imperial
Geometry of this bike.
Reach
Horizontal measurement taken from the middle of the bottom backet to the middle of the headtube.
Stack
Vertical measurement taken from the middle of the bottom bracket to the middle of the headtube.
Effective Top Tube
Horizontal measurement taken from the middle of the seatube to the middle of the headtube.
Actual Top Tube
True length of the top tube taken from the seatube along the toptup to the headtube.
Standover Height
Vertical measurement taken from the ground to the the middle of toptube.
Seat Tube Angle
Angle of the seatube.
Seat Tube Length
Lenght of the seat tube taken from the bottom bracket to the top of the seat tube (the measure is taken alongside the seat tube)
Headtube Angle
Angle of the headtube.
Headtube
Vertical lenght of the headtube.
Chainstay
Horizontal measurement taken from rear axle to the bottom bracket.
Wheelbase
Horizontal measurement between the two wheel axles.
BB Height
Vertical measurement taken from the ground to the bottom bracket (Never taken at sag).
BB Drop
Vertical measurement between the height of the axles and the height of the bottom bracket.
