GRX RX600 shifter with Deore XT rear derailleur ok?

[TonyM]

My wife wants a bike that has the 1x11 GRX groupset but the gears are 40/11-34 and she would most probably need a 1:1 ratio or even more.

I am thinking of replacing the GRX rear derailleur (GRX RX810 GS. Max 34T) with a Deore XT (RD-M8000 GS. Max 46T in 1x11) so that she can have a 40, 42 or even 46T together with the 40T in the front.

I am assuming that the Deore XT RD-M8000 GS rear derailleur works with the Shift-/ Brake Lever GRX RX600 (both 11 speed)......Am I right???

[Orbital]

I’m running the GRX 810 long cage rear derailer with CS-M8000 deore cassette 11-42t on my 1x setup. There’s also an 11-46t option but I think 42t is max for the GRX 810.

According to Shimano, GRX is compatible with dura-ace, Ultegra and 105. No mention of Deore derailers.

[TonyM]

Yess you might be very right, I think that I can recall that GRX was compatible with the road group and not with the MTB group (I have a Di2 Dura-Ace/ XTR combo but that works only with Di2).....

But the GRX 810 is officially only compatible with max 34T??
https://bike.shimano.com/en-US/product/ ... RX810.html

The GRX 812 is however officially compatible with max 42T.
https://bike.shimano.com/en-US/product/ ... RX812.html
...Is this maybe the one that you have ?

[Orbital]

Yes I have the 812. Just went back and checked.

[TonyM]

Thanks!!! That makes sense.

now let’s see if someone has done this combo GRX/XT....

I can remember that Wolftooth made an adapter road/mtb. I will check that now.

[TonyM]

found it:


https://www.wolftoothcomponents.com/col ... cts/tanpan



« The Tanpan makes Shimano 10- and 11-speed road shifters work with 10- and 11-speed mountain bike rear derailleurs. »


and that Wolftooth also sells 36T chainrings for the GRX:
https://www.wolftoothcomponents.com/col ... grx-cranks

so I could get 36/11-42 with a new 36T chainring, a RD-812 and a 11-42 cassette.....That sounds the most homogeneous combo compared to GRX/Tanpan/XT.