SHIMANO GRX RD-RX820 Rear Derailleur GG Adjustment Gauge – Y3JS9803T
Don’t just guess, use the GG Adjustment Gauge to properly set the correct gap between the upper pulley guide wheel and the cassette for flawless shifting.
Designed to work with 12-speed Shimano gravel and road rear derailleurs. The round cut-out is perfect for hanging on the home shop peg board, so you know exactly where you left it.
Aids is setting the proper distance of the upper guide wheel to the cassette
Experience shifting the way Shimano engineers intended
For use with road and gravel 12-speed rear derailleurs
RD-R7100
RD-R7150
RX-820
Original Shimano parts guarantee that all components work perfectly for optimum performance and maximum safety and longevity.