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  #1  
Old 08-15-2019, 12:47 PM
donalrey donalrey is offline
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Using Shimano GRX Crankset with Ultegra Front Derailleur

This is just an FYI, in case anyone was wondering on the compatibility of the new Shimano GRX crankset with non GRX FD - specifically Ultegra FD in this case. I couldn't find anything online regarding this so maybe this can help someone out.

Background story: I bought my gf the new GRX Crankset 2x11, 46/30t to replace an Ultegra 6800 50/34t for an upcoming trip. I bought it not realizing that Shimano recommends using specifically GRX FD because of the +2.5mm chainline of the new GRX 2x crankset. I decided to give it a go and installed it matching it with an Ultegra 6870 Di2 FD and it works just fine! I had to lower the FD and max out the high limit screw but shifting is pretty perfect. Alternatively, you can probably use one of these SRAM Wide Spacing Braze-on if you're worried about maxing out the high limit screw.
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Old 08-15-2019, 02:28 PM
marciero marciero is online now
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I just bought these to replace a 6700 compact with 46 large that got called to duty on another bike. I had thought these new GRX were 10 speed box has the "2x11" box checked rather than the "2x10". We will see how it works with 10 sp. Or I can just use an 11sp chain. As far as fd goes, I am not beyond bending 9 and 10 speed cages to get them to work, limit screw is a different story though. We will see.
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  #3  
Old 08-15-2019, 02:31 PM
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fa63 fa63 is online now
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Great to know; I am about to buy a 48/31 crankset for my gravel bike and was curious myself if I could tweak the non-GRX FD enough to make it work. Sounds like it is possible.
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  #4  
Old 08-15-2019, 10:07 PM
Zee Zee is offline
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Useful news!

Did you happen to weigh the piece before install?
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  #5  
Old 08-16-2019, 01:29 AM
PacNW2Ford PacNW2Ford is offline
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Another data point: I am running 11-speed 8000 STI with a Rotor Aldhu 46-30 crankset with the wide "disc" (+2.5mm) chain line and a CX70 10-speed FD. It all works great. I have a GRX FD ready to swap in, but it's hard to take apart a perfectly functional setup. Especially since the CX70 looks much sleeker.
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  #6  
Old 08-16-2019, 06:44 AM
marciero marciero is online now
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So mine is working great too with a 6700 (10 sp) deraileur. Limit screw adjusted out. The chain line is not too crazy either- The 46/36 cross-chain position is not too bad. I also do not seem to notice the increased Q from 148 to 151. This is odd since I noticed significant difference in the increase 145 to 148 on another bike going from Sugino to 6700.
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  #7  
Old 08-22-2019, 07:23 AM
weiwentg weiwentg is offline
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Adding a couple data points from this thread on Gravel Cyclist. wgscott reported using a GRX crankset with 6800 Di2 derailleurs, but had to nearly max out the high limit screw. Nebo used a GRX with 105 (presumably mechanical) equipment, and reported that the trim is now useless but it works otherwise. hbs reported using GRX with Ultegra equipment, works great, no details.
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  #8  
Old 09-06-2019, 07:00 PM
Morgul Bismark Morgul Bismark is offline
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My current set-up on my B-Road:
  • GRX FC-RX810-2 (48/31T) crankset
  • Ultegra R8050 Di2 Front Derailleur

The R8050 FD is adjusted near the limit of the low adjustment screw. In addition to making the low range adjustment, I also moved the derailleur down a touch due to the minor difference on the high side between a 50/34 and 48/31.

Everything works just fine
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  #9  
Old 09-08-2019, 12:00 PM
unterhausen unterhausen is online now
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this discussion is making me wonder how I got a CX-70 to shift a mtb crank with a 2.5mm spacer on the drive side.
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  #10  
Old 09-08-2019, 03:06 PM
45K10 45K10 is offline
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I just put a 46/30 GRX crankset on my wife's bike. I got it to work with a Athena FD without any issues. She is also running a Athena 11 speed RD with a Centuar 12-32 also without any issues.
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