Ineos are running XTR for Roubaix it looks like.
But using a road cassette?
I’m really curious if it works with a road cassette without any further modification (asking for a friend…)
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Maybe @Dave_Rome can let us now on geek warning 
Short answer is no.
Road and MTB are designed for different cassette geometries. Even the mid cage XTR is too long for for a typical road cassette (eg. an 11-34). The upper pulley will sit very far away from the cogs and lead to some very sloppy shifting.
Road and MTB are also designed for different chain lines (45 vs 55mm) and chain angles (boost vs non-boost), though you could probably spacer your way around that.
Road and MTB have a slightly different shift ratio that cumulates across the range (ie. How far does one click move the chain over).
As mentioned in my original comments, a system/combination that gets around those differences is kick ass and very common in gravel and on the road (see Ineos) these days. I personally have extensive experience with XTR Di2 (9250) SGS, with 12 speed MTB cassettes (native/non-native, 9-45 and 10-51), paired with GRX Di2 wireless shifters and a single chain ring. I swap cassettes depending on topography and/or course design. The 9-45 allows for very efficient chain lines and lovely, almost linear gaps around the mid block for flat-ish courses for example. The 10-51 is much more “jumpy” around the mid section.
Hope that helps.
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Last year at Spoken - when wireless XTR was really new - one of the Shimano guys had the long cage RD and 10-51 on his gravel bike and said it was fine. IME Shimano RDs will always work with a larger or smaller casette than the specs say, but I’ve no idea how much tolerance there is with this generation; I’ve not had a chance to experiment. (I wouldn’t be at all surprised if 11-34/36 worked fine, but who knows?)
The one thing I’m confident about is that the specs only ever list things in the same group as compatible, which is untrue and unhelpful.
Really interested how Ineos, Total Energies etc. did this at Roubaix. Looks like a road 11-34/36 cassette. Would be a great setup for crits, but 10-45 and a big chainring is a safer bet I guess, I just hate the 10-12 jump.
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The 9-45 cassette is 9, 11, 13, 15, 17 and so on. If you mashed it together with the 10-45 cassette you could have single tooth gaps from 10 (or 9, if it fits on your bike) up to 19. Requires buying two cassettes, but XT level isn’t all that expensive.
Before anyone buys anything to sttempt this I suggest they look at the EVs (Exploded Views) of the casettes at si.shimano.com - it’s almost certain to be impossible, but even if it was none of the shift ramps would line up. Most of the larger cogs are on a spider too, so there’d be a horrendous gap at some point, to go along with the terrible shifting.
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That is a good point about the ramps not lining up, I didn’t think about that!
The largest loose MS cog looks to be 19T after which there are large spiders 21-45T), so while it might be possible to cobble together a 9-19 cassette somehow, I think that’d be it. An 11-23 or 12-25 11 speed cassette plus an Ultegra RX RD would make more sense, assuming no low gears are needed. And no, the RX RD isnt rated for <11-28, but works fine with 11-40 & 2x so should be fine. (There are third party close ratio 12 speed cassettes too, for instance 11-26 from E. Dubied, Recon, etc.)
The bike has finally come together, I bumped up the chainring to 58t and after much consideration I went with the 10-45 rather than the 9-45. It’s only added about 200g overall to the bike weight (was about 7.5kgs before the changes).
The weather around Sydney hasn’t been too nice so haven’t had a chance to take it out on the road. But on the rollers the shifting and overall performance was just as fast as the Duraace.
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What a weapon, looks amazing.
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I’m wondering if XTR RD with Classified 11-34 cassette would work.
Van der Poel is running XTR and road cassette on some stages of this years tour. I was trying to post a link but I’m sure it’s been reported on escape collective and elsewhere.
No input on the gearing. Just want to say that bike looks absolutely insane. Can’t believe that frame is 7 years old, holds its own against today’s bikes imo!
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What are the wheels on the Venge?
Also kudos for choosing the Black Inc. handlebars—their angularity really matches the bike’s!
and that’s to say nothing of having two adjacent cogs that are both threaded for a locking lol. I’ll just tell myself he was taking the piss…
Do these rattle? I had to get rid of my trek RSL cages and bottles that came with my madone as I couldn’t stand the noise
Resurrecting this thread because I’m considering a 1x road setup with a XTR short cage RD and 11-34 cassette as run by a few teams during Roubaix and the Tour. Has anyone tried this?
I’m running a Classified 48T chainring with an 11–34 cassette and 12-speed GRX Di2. It works great, but I have no experience with XTR Di2. I’d guess it works just as well as GRX, though.
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