um, YES, to both y’all, amazing. Sure, UDH already-compatible works, duh me, thanks PMW. And way to simplify DEVINCC! holy moly, and also the antlers. Can hold hats AND fancy-pants dropouts! Who knew?!
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That’s how they should all be. LOL
Hi Friends,
I have a question regarding the mounting angle of the UDH when attached to a bike without rear suspension. Is it necessary for the horizontal line passing through the UDH to point toward the BB? See the picture attached. 
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I’d imagine that for a hardtail you have quite a bit of wiggle room there as it works with all kinds of suspension designs around the sag point. I doubt anybody will be able to give you a qualified answer tho
The new Sram Transmission system does not have a B screw anymore, so if you want that to be compatible, I think it’s highly advisable to follow the spec.
Regarding full suspensions, even though the derailleur will rotate non-concentrically with the BB, you are generally not shifting while bottomed out. That is why in those situations, the orientation of the derailleur does not matter.
If using normal derailleurs, SRAM and Shimano give recommended specs on the derailleur location and angle. As long as you don’t stray too far from that, your shifting should be fine.
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We’re moving forward with a AXS/Transmission sliding insert. We can be 100% within the specs, but the compromise is that axle center shifts down and back 5 mm. On a typical modern mountain bike, that’s about a quarter of a degree change in HT/ST angles. While it is possible to reduce the shift some, 5/5 will give us a part we feel is robust. This really only applies to retrofits. Any new construction can account for the 5/5 shift and correct for it.
Our on-staff former XC and DH pro rider says he will be able to recognize a 1/4 degree change, but he’s special. I’ll say that changing tire pressure or size is a 1/4 degree.
We do have an AXS/Transmission drivetrain on hand. We will be doing full scale, genuine 3D confirmation of clearances and dimensions.
There will be a matching left side insert with the 5/5 shift.
Here’s the question: Are riders going to freak out, or feel that they can live with the shift to get the drivetrain they want?
VERY preliminary pics:
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I’d venture if you told zero people it moved the axle then zero people would even notice. If we spend a lot of time focusing on that as we discuss it then it will snowball into an issue that doesn’t really exist. The difference will be pretty subtle and worth it for those who are seeking the broadest compatibility, which for our customers is more important. Can I do singlespeed, Transmission, regular derailleurs etc? That’s the win. Thanks Mark and PMW for being open to this compromise and getting it done for us all!
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I highly doubt anyone will feel 1/4 deg change but that will be the tradeoff for wanting this transmission on a not-new frame. I think it’s great to even offer the option and it’s one of my favorite selling-points of Sliders and Rockers = futureproofing when stuff like this (and new brake standards) come along.
I actually made a frame for myself that had tilted sliders so i could get a ~5mm change in BB height (and the angles changed too) so i could get a little bit of compensation for smaller wheel/tire combo, similar to what EBB’s are used for with BB height but also allowed bigger tires when slid back.
If people actually do notice a change, they can swap tire sizes or fork sag to compensate, 5mm is almost not worth mentioning as an issue, IMO.
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OK, mostly in hand!
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SRAM: “Really difficult to break this thing. Like . . . REAAAAALLLLLYYY difficult.”
mark_pwm: “Whatever you say, Chump!”
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The Mark flexing on us peasants by throwing money away GIF is the best thing that has come from the SRAM launch. I will see if I can get some media outlets to post it 
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We are working on inserts and dropouts for as many styles as we can. Because of demand, the first one we’ll have ready are inserts for sliding dropouts. This version will accept the UDH. As much as possible, we intend to make all options UDH compatible, but for small round versions, we may not be completely compliant. I don’t think this is a problem, as the goal is to have a mount for SRAM T-type. For these dropouts, we can make a hanger if there’s interest.
Next on the list are Rocker inserts, but we haven’t yet confirmed that we can do it. After that, round flanged dropouts, diameters TBD. Finally, we’re cooking up a version with an eccentric to fine tune wheel position. If we can fit PolyDrops, we’ll do it, but space limitations will need to be overcome.
We recently printed some prototypes of sliding inserts. We’re really happy with the results, and want to thank Chumba (@Nivloc ) for the help. Because of geometry limitations, axle center has been moved back 9 mm. Axle height is unchanged.
Chain clearance was one of the challenges, photos from Chumba show that clearance is no worse than most current builds. The great thing about all this clearance is that these inserts will retro-fit to any existing frame with our sliders. This bike was built with the slot horizontal, angled slots may not have this much room. These are optimized for our sliders, no guarantee that they’ll fit any others. There will be a matching PM160 available for the left side.
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Thanks for all the effort @mark_pmw and PMW team!
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Thanks @mark_pmw!
The sliders look great. It’s surprising it all fit considering how massive the UDH spec is.
I decided to get my round t-type dropout 3d printed in plastic to do a test fit with the new derailleur. The part should arrive in a week or so. I’ll post photos and notes here soon after.
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Thanks mark! We’ve been getting allot of UDH slider requests, stoked you guys are always ontop of it!
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My test print arrived but the design was a flop. I forgot to account for the 14.4/15mm clearance offset in the UDH design spec, so the hooded flange restricted the derailleur’s movement 
Back in Fusion, I adjusted the outer diameter all the way up to 38.1mm. Even at that size the clearance offset would prevent the use of 19mm chainstays.
At this point, I think a hooded dropout cannot simply be made out of round stock. The T-type derailleur arm is too large. But maybe the design wizards at Paragon can figure out a tidy solution.
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We’ll do what we can. This is good info, and we’ll use it in our designs. We’re finishing up the slider insert now, when that’s done, we’re all in on a solution for this.
Thanks for showing!
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