Index Rear Derailleurs and set Front Derailleur limits using E-Tube Project
Learn how to set up your di2 front derailleur electrical limits and index or micro-adjust your di2 rear derailleur using E-Tube Project 4.
Rear Derailleur (2x)
GRX RD-RX815
If you've been looking at GRX Di2 components you may have seen that there are two rear deraileurs. This RD-RX815 and the RD-RX817.
While the RD-RX817 supports a greater cassette range of 11-42T, that specific derailleur is not meant to be used with a front derailleur. It is the 1x-only GRX rear derailleur.
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So if you want to use GRX Di2 and run a front derailleur, this RD-RX815 is the way to go. It has a total capacity of 38T, with a top sprocket max of 11T and a low sprocket max of 34T (min 30T).
Both GRX rear derailleurs feature a clutch mechanism, just like the Ultegra RD-RX805 and the mountain bike rear derailleurs. Shimano call this the chain stabiliser. It can be adjusted and prevents chain slapping (or worse, dropping your chain).
Specifications
- Model code
- RD-RX815
- Series
- GRX RX815
- Weight
- 287g
- SD50 ports
- 1
- Max front difference
- 17T
- Total capacity
- 38T
- Low sprocket max
- 34T
- Low sprocket min
- 30T
- Top sprocket min
- 11T
- Top sprocket max
- 11T
- Pulley teeth
- 13
- RD Type
- Shadow RD+
- Clutch
- Yes
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Installation Guide: RD-RX805 / RD-RX815 / RD-RX817 Di2 Rear Derailleur
Stuck installing your new Di2 rear derailleur? Read how to install the RD-RX805 / RD-RX815 / RD-RX817 Di2 rear derailleurs.
Understanding Di2 derailleur specifications
What is a rear derailleur's total capacity, really? Why is there a top sprocket minimum? And what about front derailleurs? Chain line, total capacity, Top gear teeth? This page explains all of those, and more.