Having a 1x mountain bike, I always considered a one-by for the gravel bike as well, but the range on available systems was somehow limited, as I use the bike also for some road riding, so the 11-42 range available on the GRX 11 speed was a no-go. (New post coming up with the "science" of 1x).
With the launch of GRX 12 speed, the rear-derailleur was "updated" (basically it's a M8100 mountain bike derailleur with a tweak on cable pull), which means a 10-51 cassette was possible.
Upgrading to GRX 12 speed would however be... expensive, as it would be necessary to replace shifters (super expensive), wheel hub to microspline, basically with the exception of the chainset, everything.
With the launch of the Deore 11-51 11 speed cassette, this made things very tempting.
Basically all information out there is that using the 12spd rear derraileur on a 11 system would NOT WORK.
However, I saw a youtube video of a guy claiming it DOES work.
Looking at the comments, most of the people that tried it mention it does not work, however I had to try.Got a 50% deal on the RD, the cassette can always be used for the mountain bike, so let's go.
Installation was simple enough, but ... spend some time trying to get the thing to work, to the point it "almost" works, but not.
I can get about 9 of the 11 speeds to work correctly, but it misaligns with each click of the lever, so ... basically a different pull-ratio. Close, but no cigar.
After some time tweaking it, it looked good on the stand.
Took it out for a ride and... nah.The 13t cog clicks and jumps, and the 51 and 45 "tick" and I had to constantly hold the lever on a steep ramp so it would not jump out of the '51.
basically this protrusion |
Removing that, one can pinch the cable BELOW the bolt, so it gives it like a 5mm longer lever of action for the same cable pulled. This should be enough to move the derailleur the extra bit it needs to shift an 11 speed cassette. ( The spacing of cogs on 11 speed is slightly larger than 12 speeds, so it all makes sense).
I grabbed the dremmel, and cut it off, grinded it to make it smooth so the cable does not fray, and gave it a try.
Now I'll just put some nail polish, or touch up paint or whatever there and here we go !
If you try it, let me know how it went !