Rear Derailleur (1x)

Rear Derailleur (1x)


If you've been looking at GRX Di2 components you may have seen that there are two rear deraileurs. This RD-RX817 and its lightweight cousin, the RD-RX815.

The RD-RX817 was developed by Shimano specifically for use in 1x bikes. This means that running this rear derailleur with a front derailleur is officially not supported. There are reports of users installing a front derailleur anyway, like this user on If you do, keep in mind that this is not Shimano approved and your shifting quality could suffer.

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