Hi all, I wanted to suggest a frame builder community effort to get more included in the release of these new drivetrain products.
I am disappointed at SRAM’s embrace of the big box companies with the Transmission launch on OEM builds, getting them access to designs far ahead of us and not including builders on their new compatibility chart out of the gate. Now we are all left to scramble and catch backup. Luckily the good folks at PMW have our back and are helping to get options for us all with UDH. Why couldn’t SRAM get them what they needed months ago?
I met with our local Shimano rep this week who had no idea that SRAM did not get all this Transmission info to us ahead of time or include us. Where were the derailleur samples for us that all the magazines had? Why couldn’t we get a 3d rendering of the derailleur or a 3-d printed mockup. This above is what I talked with him about. Our local Shimano rep said he could advocate to get us those things for potential new product launches.
Learning from the Transmission launch I propose we get more proactive asking for access sooner. If enough of us do it I think we might get a result. With Shimano looking for any edge on SRAM, offering them our collective support with a product launch may be attractive to them. They tried this with GRX Limited, but they didn’t get it out to everyone, only some of us so I don’t think it took off. It didn’t seem like a big success, but I don’t think that was the product people were looking for. People will want any updated tech on GRX and they will want Direct mount Shimano MTN drivetrains at a whole other level then GRX Limited. I can’t confirm those things are coming but the rumors on the internet tell me they likely are.
So I am proposing we brainstorm a way to attract their attention enough to make it happen. Thoughts? My initial thought is to draft a letter, and then get that to our local reps and inside Shimano sales reps well in advance of any new launch we can only guess is coming. Then we would each follow that up with a call or visit with those reps and ask them to pass it up the chain.
It sounds like Shimano USA is quite a bit nicer to work with than Shimano over here in the Netherlands. I have been trying to get a regular shop account with them for 4 years, and it always stranded when they found out I didn’t have a real shop but was just working from a workshop. The Limited edition GRX didn’t change that over here, so I gave up on Shimano over here. On the other hand: We custom builders can shift much much quicker than the big brands, so for me it is not really an issue. Actually I already had a UDH compatible dropout in the works, and that matched fine with the new Transmission derailleur.
Apart from that I think we custom builders make up such a tiny part of the market that we are just not interesting enough to get us all parts or drawings. That will just increase the chance of someone blowing their carefully guarded secret…
This is a great idea. Everyone knew Sram Transmission was coming, what a year ago, and yet we really couldn’t prepare for it.
I do worry that Shimano might not want to share the info with all of us small fries. But if we could nominate one representative for our niche industry I think it makes sense to promote @mark_pmw.
If he got some early release sample derailleurs, then the PMW team could prepare to produce slider inserts and dedicated dropouts if needed. Then with production samples in hand he could reach out to builders he trusts like @Nivloc to get feedback on the designs before the official release.
PMW gets all of Shimano’s tech updates. We have access to all of Shimano’s 3D files. We have an OEM and framebuilder account with Shimano. We worked hard to get here, and signed a lot of NDAs. Our relationship with Shimano is good, and they are generous with the info we need.
All of this should help! Years ago, Shimano had a marketing person that worked specifically with small builders. The market isn’t big, but there’s a lot of innovation and clever thinking with small builders. Small builders made T47 happen, now it’s available worldwide, and is seriously challenging English BBs.
I’ll be in touch with Shimano and see what they can do for us. With previous sensitive releases (flat mount) the info was embargoed, and we signed an NDA for it. It was really nice to have the info ahead of time.
We’ll keep you posted, but if Shimano says we can’t disclose anything, we won’t.
Update: We did hear from a contact at Shimano. To paraphrase, there are no frame changes in projections as far out as 2025.
What does that mean for PMW and small builders? We will continue to make dropouts with conventional hangers, until sales are so low that it’s not worth it. We are also continuing to develop more options for UDH/T-Type dropouts. We have a solution for sliding dropouts, we’re working on one for rockers, and have designs for a titanium round dropout that is 100% compliant, symmetric and can take 7/8" CS and 3/4" SS.
We see UDH/T-Type dropouts as a win/win situation. If a rider wants SRAM, they’re covered. If a rider wants any other derailleur, they’re covered.
Smallish orders can be pricey, because the set up time for 10 pieces is the same as for 100. If it’s similar to something we already do (like most bike parts), we can usually figure out a way to do it. Send a drawing, photo or napkin sketch over, and we’ll take a look!
The last update from @mark_pmw was there were no frame changes until 2025. Well we have almost arrived and it appears Shimano is cooking something up.
There have been several teasers to the new Open Upper Concept and in some of the now deleted copy there was mention of “a new, as of yet unannounced Shimano derailleur standard.”
Of course the first thought is that it would be some sort of adaptation to the UDH interface (which it still could be) BUT it looks like Shimano is actually working on new FRONT Derailleur Mounting Standard. Who’d have thought.
I found this spy shot of the new Upper Concept Frame deep on a discord channel.
I think it’s more likely that there will be some sort of adaptation to the UDH dropout to allow for a b screw adjustment (54) shown in their patent drawing. So there might be ANOTHER anti rotation design requirement
It’s actually not unneccassary. Its design to catch chains if they drop of the bottom sprocket and not jam into carbon frames when a non Transmission der is used. A moment happened to me where I put on a new XT derailleur and forgot to adjust the outer stop screw. Mid race I’m in the smallest sprocket and the chain drops onto the fin and just runs along rather than jamming against the frame. If it was just a rotation stop it cound be done so much smaller than they have. I think you’ll find the Transmission derailleurs don’t allow the chain to go that far across, the system is designed to excat dims, which is why they don’t have the fin but they do have the space for a chain to fit in there on the rare chance it does drop off.
…and I’ll say it again. I will bet my house that the new direct mount Shimano derailleurs will install into the open source frame end specification. They don’t have a choice in this case.
There are some leaked KTM mtb bike shots floating around with the drivetrains partially blurred out and the spec sheets indicate new xt and xtr di2 groupsets for 2025. Must be getting closer to a launch.
It looks like Shimano may be sticking to a standard hanger mount rear derailleur for this generation at least. Here’s the link to the rumor mill for those interested.
To be perfectly fair, the UDH/T-Type specs have been available on the dedicated UDH site, including 3D models with the clearance envelope very well defined, since it was first launched a few years ago. It has all the info needed to make a dropout/frame design that is compatible with both the replaceable hanger and the “full mount” derailleur as they call it.
Having a 3D model or even a 3D print of the actual part is just a “nice thing to have” for visualisation purposes and not strictly necessary to achieve a compatible design.
In my experience it’s much more difficult to get info out of Shimano. I’ve only just recently managed to get in touch with the right person who can grant me access to the official tech docs and even 3D models. Will be good to not have to scrounge around on the Internet to try to find outdated PDF documents with their tech specs.
I know there’s this certain very opinionated engineer out there who is staunchly against the fin. Let’s not fall into the trap of thinking he’s correct even though he insists he’s always right about exactly everything and all other opinions are invalid…
The fin on the hanger serves two purposes. Anti-rotation (on some, but not all) dropout designs, and as @DEVLINCC mentioned; frame protection against the chain dropping due to poorly adjusted standard derailleurs. This can certainly be a big problem for carbon frames. Maybe less so on steel frames, but you can still mess up a nice paint job or kill a chain that would otherwise be undamaged or at least salvageable in the case of a chain drop/jam.
An anti rotation feature could be less obtrusive than the current UDH fin. That would allow for a more compact dropout design. A feature than protects against incorrect derailleur adjustment is beneficial, but not if it increases the overall dropout dimension.
Like I mentioned, the fin is not necessary for all dropout designs.
An example is included in the offical SRAM UDH spec availble for download on the Universal Derailleur Hanger website.
So if the tiny little tip of the fin is so bothersome, it can be eliminated using a dropout design that restricts the rotation by hitting the back of the hanger tang (example #5 in SRAM’s “Possible Hangerless Interface design variants” document).
The fin stop on the dropout is not necessary but the fin remains on the ‘universal’ hanger. The fin(and the clearance required for rotation of the fin) forces the location of seat stay attachment points away from the axle. This results in less compact dropout designs.
