Had a weird idea for a setback version but it turned out pretty wacky looking. I’ll need to refine it some more. I don’t love the hidden bolt head.
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It’s been a second since I posted an update on this, but I’ve been iterating away at a design. I decided to abandon the Thomson hardware because I just couldn’t get it to look nice with any degree of setback. In my search for an easily source-able replacement, I found the Ritchey 1-bolt system. The saddle rail clamps are available directly from Ritchey or QBP at a pretty low price.
This is what I ended up coalescing on. It’s a touch less than 60g and I’m sure I could pare that down further if needed. I ditched the weld-in seat tube topper in favor of just 3D printing all of it. As far as I can see, there’s no need for 2.3mm wall thickness there. I’m not in love with the drillium windows, but they get the job done! I have a Ritchey post in the mail and will be mocking this up with a plastic 3D printed prototype to make sure all the angles and spacing align.
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Ii don’t know if the windows are a great idea. I don’t have firsthand experience, but this article mentions issues they had with the metal warping slightly during printing leading to some finish quality and dimension issues. It could have been the design, the print orientation, or some other problem causing the issues, but the issues were still there.
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I’ve been talking to Spencer a bit about this project! My thinking is I can slightly undersize the seat mast hole and ream it to fit like a normal seat tube. Though it might destroy my very nice Silva reamer 
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I feel like you’re always just one step ahead of me. lol. Also, as a completely off topic remark, I share my name with a lot of cool people.
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Eva that design looks beautiful! I know Speedvagen used to just paint the Ritchey Topper and it actually turned out really nice! If you’re looking to reduce cost that could be a good route! Maybe add some fancy drillium?
I’ve always thought about making a topper/seatpost around the Schmolke Setback Post design. They use the classic ultralight pin design synonymous with most weight weenie brands with a slight twist for setback. The pin design could allow for the topper to also be made out of carbon. Bond the Darimo Carbon Seat Clamp to the bottom and It would be wicked light!
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Aw thanks!! I’m using a 27.2mm mast so the Ritchey one is out unfortunately. It does look pretty slick. If this one doesn’t work, I’ll give the Woodman version a shot which is almost certainly lighter but not haute custom titanium.
The Schmolke stuff kind of terrifies me tbh. I’m sure the more seasoned weight weenies wouldn’t think twice about it but dang there’s just not much material there!!
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Ah that makes sense. Perfect opportunity to bring the custom Ti hautness!
I see where you’re coming from with the setback hardware but all the straight versions from Darimo, MCFK, Tune, Schmolke, AX Lightness and Woodman offer a fair bit more rail support.
Are you wanting to run a setback so the bike can get tukt? Is the 2022 Best Couch Bike Award Winner going tukt on 2024?
Partially that, partially just making sure I don’t design this bike into an un-fit-able nightmare. I’m trying to squeeze a straight seat tube with 2.1" tires and 425mm chainstays which is pretty tight. I discovered that I like racing this past year and short chainstays have a bit more pep in their step! But that’s a topic for another thread 
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Sorry to derail, but I’m very interested to hear what you have to say about this!
This isn’t as good of solution for a carbon ISP but I always admired the Custom Thomson Wedge Design Rob English uses for many of his ISP Bikes.
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It turned out pretty good! I made a few modifications from the design I posted above and sent it off to be printed. It did end up needing to be reamed, but I was expecting that. Got the printed bit down to 46g, the Ritchey hardware is 54g, and the bolt closure I stole from Wolf Tooth is another 4g, so just a hair over 100g for the complete set. I’ll take the 14g penalty over the Woodman topper for the ease of adjusting saddle angle without having to fiddle with a bolt hidden underneath the saddle.
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