11-40 is meant to be doable in the 2x rear mech without even a hanger extender. By going to 52/36 you’re reducing your front capacity to 16 teeth compared to 17t on the 48/31 chainset so should probably work from a rear mech point of view. Might want a hanger extender or longer aftermarket pulley cage depending on your setup but there are enough stories of it working without either.
You probably want to use an ultegra or DA front mech with that chainset though - just so you’re in the sweet spot in terms of spacing. But that might reduce tyre clearance so that has to be considered.
It will be a very long chain though!
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I thought 11-40 seemed like a lot too but there are numerous reports of it working fine. And not just videos from a workshop, I know of at least one person that raced the GBDuro on that setup without issue and have seen (but can’t recall) other reports from hard usage in the wild.
Are you saying you used RX800 rear or front? The rear mech doesn’t care what size your chainrings are, only the difference between them. So 50/34 is the same as 52/36 (except for chain length of course). 53/39 is a smaller jump yet again. But from a RD point of view there’s no difference between 56/40, 52/36, 50/34, 46/30, or 40/24 (even though the combos at the extreme ends of that don’t exist to my knowledge).
This is pushing it to the max. Garabuk 11-46 (11spd) and RD-RX817 (supposed to support 11-42) with a 2x up front. It sorta works, but not sure If I’d race with it as the lowest gear 31/46 is really low for gravel and makes for some gear jumps that aren’t quite where I’d like them…
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With the FD? No, but 100% cannot run a road cassette and have smooth shifting across the range. So you have to run the cassette with the spacer. If I want to run an 11-32 or smaller I have to swap back to the RX815 rear mech.
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For reference, the SRAM 11-36 is like 30g heavier than the Ultegra 11-34, and 50g lighter than the XT 11-40… So it falls right where you’d expect it to land for any of the larger manufacturers cassettes of this size. It’s been my go to on my 2x GRX setup, paired with a 48/32 up front for any terrain.
Additionally I have ran a 11-40 out back, and the stock GRX derailleur handled it fine with the same chainrings. If you’re looking to go any larger in the cassette, you’d probably want to tighten up the front chainring spacing, by going 46/34 or something similar to that as you’re asking a lot of the derailleur in regards to take up.
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Yo guys, just please open another thread to discuss that. It is not relevant to the topic at hand.
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Amen. Let’s keep this thread about the next GRX.
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What are the odds we’ll see anything before July?
Unbound perhaps?
That’s when I would launch it if it was my product! I think someone on the WW forum thread said they were told autumn though - so maybe Unbound launch and autumn availability? Or if it really is autumn for both launch and sales then perhaps they’ll align with a major CX event? Even as iconic as Unbound has gotten, there’s still more media coverage for CX at this point.
I think it’s likely to be factors like the megaphone of Unbound coupled with availability. OEMs first, then as group sets and separate components. Doing a big announcement and not having it on bikes people can buy is a paper launch that does nothing when it comes to sales momentum.
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I have delayed my race bike purchase for this release, any idea when should we expect availability?
Yeah but hasn’t Shimano announced way before consumer availability many times before? Maybe my memory is false but that’s what I recall.
My bet would be on Unbound announcement regardless of availability.
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12 spd mechanical… 
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Just in time to make my un-installed GRX Limited Edition 11-s obsolete 
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Limited edition as in the polished stuff?!?!?!
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Yup, snagged a 2x setup via good Pro Deal and have it planned for my pending gravel build. Currently aiming towards the All-City Cosmic Stallion Titanium.
Found another person who made a build very similar to where I am headed:
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When your name is Ben Delaney? 
I can cut him some slack in this regard, though…he probably shot this “on the fly” and didn’t have a lot of time to make notes, double-check everything as he was doing the vid. he at least made the corrections in the video once he released it.
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I’ll trade you a Sterzo Smart for the grouppo…
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