Originally Posted by
paramount3
zen Thanks--46/30 GRX crankset with GRX FD would be the plug-and play solution (if I could actually buy that FD). But the 46 is higher than I need, and 30/36 is not a low enough gear. I'm hesitant to go to goatlink-dependent solutions for the RD. With the RD-RX812 that I have, any 2x system will be going beyond the stated total chain capacity (but I would try it anyway), so yes, I might have to switch to the RX400 or the RX810.
You should be able to run an 11-40 cassette w/o an extension on the GRX derailleur. Here is a video of the setup with an 11 speed GRX system using the 48/31 crank. With that setup the only caveat is not using big-big (48-40).
https://www.youtube.com/watch?v=wNeYYM9_aeM
Not trying to sway you either way (I like to fiddle with things too), but the GRX 600 46/30 crank, 400 derailleurs, and a Sunrace 11-40 cassette would most likely work well.