As I said convention, radically dropped and elevated seat-stays would probably fall outside the double diamond UCI standard frame “boxes” and be illegal as well.
I wouldn’t be surprised if the UCI mandated max tyre diameters for road and for gravel bikes.
I’m building a MOG now, and am sticking with the XXSL and 10-52 for this exact reason. Here in the east we’ve got some real steep stuff too, just usually not as long as what you run into out west. But, definitely don’t want to sacrifice the 52 in favor of the 46.
Edit: Although, I’ve done dumber things than having the 13SP Cassette, Derailleur, and a new chain that I could swap in. Wireless makes that not much of an issue.
No, getting rid of the FD enabled new suspension designs and geometries. You can find some more details in this singletracks.com article. This is not a controversial point.
Shimano held onto the belief that there was a future for front derailleurs on the MTBs side until the previous generation (M9000-series XTR and lower). They even threatened reviewers if they converted their 2x test bike to 1x. That was way past the point where the MTB industry had already decided that mountain bikes should be 1x.
I reckon the same is happening for gravel bikes now, Shimano is (almost?) missing the boat.
Disc brakes allowed for much bigger tire clearance as rim brakes are limited to 28 mm. Yes, I know V-brakes exist, but they had been displaced by disc brakes for good reason on the MTB side.
Since aerodynamic fairings are not UCI legal, rim brakes have an aero advantage, especially if they are hidden inside the frame. (This typically compromises performance as they are exposed to more dirt and grime, and the cables have to take a more windy route.) There are some compromises you have to do for wheels with rim brakes as the rim needs to be strong enough to serve as a brake track.
This.
I really hate how slowly road bikes have evolved compared with tri bikes and mountain bikes. The way disc brakes (as an option!) were allowed into the (road bike) pro peloton was ludicrous. They acted as if this was completely new, unproven technology from Mars.
There are quite a few tri bikes that do not use a double-diamond shape. So for special applications, that might make sense.
I think looser restrictions on tube profiles and such could leave tons of room for innovation. Triathletes have had integrated hydration systems for how many years now? That seems like a pretty good idea to me, at least as an option for some riders.
No, getting rid of FDs had nothing to do with new geometries, ( its not even mentioned in that article you linked?) its all about suspension design, like I already said.
Open the article and search for (the section headers) “suspension performance”, “tire clearance” and “frame structure”.
Chain tension is a huge factor in suspension performance and a FD messes that up as you can have very different chain tension at similar gear ratios. Feel free to search for more articles on that subject.
If the Lefty works… 
I know, I’m agreeing with you!
Sure….but my comment had nothing to do with a double diamond design. It was focused specifically on the idea of removing the drive side chainstay. The chain forces are horizontal and if you remove the drive side chainstay, you are moving the primary structure resisting those forces. So you would need to beef of both the seat tube / BB area as well as any kind of seat stay structure to such a degree that it would be too heavy.
It is also one of the reasons why elevated chainstays are really that effective. Back in the 90’s, there were a number of elevated chainstay bikes and they almost all had problems with throwing the chains because of frame flex. The Gary Fisher HooKooEKoo was a prime example (combined with the stays actually breaking).
Dropped chainstays bring chainsuck into play…a really bad problem for carbon frames. 
I thought the UCI-mandated double diamond has two chainstays, so what you are proposing was not a double diamond design in the sense of the UCI. So in my mind, we were talking about the same thing.
Maybe you are arguing that removing one of the chainstays in a double diamond design is still a double diamond frame, just one that isn’t UCI legal. I don’t have an opinion on that (it is semantics to me, chiefly because I don’t know whether there is a proper term for such a design).
There are other ways to go beyond the double-diamond construction (e. g. no top tube, no seat stays), which is something you see in tri bikes. There were also Y-shaped mountain bike frames in the 1990s. These no longer exist. However, giving bike manufacturers the freedom to go beyond is IMHO important, because this experimentation can lead to bikes that are better for customers in meaningful ways. When I hear whispers of the UCI limiting tire sizes, I think this is the exact opposite. If in 20 years the TdF is won on 2.25" rubber (I’m being facetious), because that is faster, then that is what riders should and should be able to ride.
Sorry, let me clarify….I am not making any point re: double diamond frames or UCI design regulations. @JonGreengrass said that you could remove the drive side chainstay as an option to increase tire clearance. Such an idea is impractical because it would be structurally compromised. It would either suffer from drivtrain issues or be impracticality heavy.
I couldn’t cares less if it was a double-diamond frame or complied with UCI regulations.
Ah, ok. Indeed, I went along a different tangent (that UCI regulations stifle innovation).
From a technical point of view, I agree. Unless you want to use the “natural flex” as a sort of suspension (which also deflects sideways, unfortunately).
100% accurate.
That’s also a feature of UCI regulations, not a bug 
Is the front ring on 13SP Red XPLR compatible with a 12 speed chain? If so, agree that makes it pretty easy to switch back and forth if you have the cassette and derailuer.
Yes. It is reportedly the same for both.
It damn well better be, I have Red XPLR PM cranks with a 44T ring showing up tomorrow 
I’ve seen other people reportedly running this setup and Looks like the exact same ring interface as on the MTB cranks, will be able to confirm soon.
x-post for write-up:
Back to the tire discussion.
Not making a particular assumption here, but found it interesting that Brennan Wertz just won gravel nationals on a Mosaic GT-1 iAR, a bike with 40mm tire clearance. I can’t tell from the photos, but appears to be a rene hearse slick. Not sure what width.
He beat some top racers - Keegan, Russell Finsterwald, Griffin Easter, Dylan Johnson, etc.
It’ll be interesting to see some recaps. I have no idea what anyone else was running, but I’m sure we’ll see some setups soon.
Based on the 6sec gap, i bet it played out with him attacking at the end and everyone looked at eachother not wanting to pull.
Dylan is a good racer, but not a top one.
Tires are a small gain, but in road like race courses, tactics and pure power are gonna be a much bigger gain