This is the main reason why we use paragon round dropouts on our production bikes: hanger support down the line. These dropouts are both easy to design around and easy to fabricate with.
However, just because this is what we do now, does not mean this is what we want in the future. The paragon stuff is great, and the company is amazing to work with, but I think there is room for an engineered hanger that is opensource (well-documented and free to use and modify).
Because the paragon hanger bears the sheer load, it needs a very precise fit:
This makes it difficult to paint. We had to strip and respray several frames that the powder coaters messed up (not the Paragonâs fault, but itâs also not an uncommon mistake).
Their snapring dropout is similar. It requires a precise bore and is not field serviceable (my biggest complaint):
I really like the standardization that UDH brings. However, the UDH standard is free to use, but not open source. Those two phrases are used interchangeably but fundamentally different. SRAM owns the patent. They can use this to lock out competitors, go after dropout manufacturers, and monopolize drivetrains. I am pretty sure they would not do this, but if the standard were open source, those scenarios could not happen.
Open Source Solution:
This is why I am in favor of creating our own open-source hanger architecture for metal bikes:
The hanger can be designed to look good and work well with all sorts of dropouts
1.125in round, 1.5in round, sliding, 3D printed, plate, etcâŚ
The hanger dimensions and dropout design will be well documented
Open source allows people to freely use and remix the design
Hangers will be standardized and readily available
Hangers could be produced by anyone
Paragon/BFS will still be able to make and sell their dropouts and hangers
If itâs not compatible with the coming direct mount Sram mechs itâs a dead end. Customers for custom frames are going to want to hang the latest and greatest drivetrain off it.
Once SRAM releases its drivetrain, I will let the market decide.
However, I am not too concerned:
If customers truly wanted the latest and greatest, they would just buy a carbon full suspension (and most do). They wonât be buying a $6000 steel/titanium hardtail
UDH is only for mountain bikes. Custom frames encompass road, gravel, cross, commuter, urban, etcâŚ
There will always be backward compatibility or older parts avaliable
My perspective is based on our existing customers. Not to say that this market will stay the same, nor should that prevent people from trying the UDH standard for themselves!
@Daniel_Y your use of graphics is above and beyond
Totally agree on the tight tolerances of the PMW hanger on their round drops. Itâs been a peeve of mine too having spent way too much time cleaning up the powder after getting a frame back just to put the hanger on it. Itâs not been an issue with bike painters but most normal powdercoaters will coat it or not tape it off well. I also am not super fond of the Bobi hanger systems but i live with it until I find a flat mount dropout I like better (and is readily available).
I mostly now use the Syntace style when using hooded dropouts. I love the hanger and shear-bolt design, and makes it easier to prep after powder. I like how even though itâs a Syntace product, Paragon had started making all the dropout bits including the axles in all the various sizes since Syntace doesnât.
The tight tolerance thing is likely a design compromise since they make the same dropouts in ti and steel. Itâs great for Ti to have the tight tolerance but not in steel. Happens with several other items that in a perfect world would have separate designs for Ti and steel.
I donât have much to say about the UDH since I donât know enough about it, I wonât adopt it until itâs proven necessary. I just wish if âweâ are going to start a new standard that everyone that makes parts has to be on board. Otherwise weâll be making Shimano specific MTB frames or SRAM UDH MTB frames?
With the Shimano DM derailleur at least one can use it on a normal hanger or use a DM hanger. With Eagle 12 spd it was a different cassette driver but could still use the same wheel and dropouts if the frame was first built with Shimano. So it should be open source like you say @Daniel_Y . I really donât want it to go the way of what happened with BB shells several years ago. That was nuts. Everyone manufacturer had their own and expected everyone to follow since they thought theirs was the best.
Thanks mate. Those first ones were hand cut but am about to order a bunch of laser cut ones in 4130. The insert will be out of 304 so the bare surfaces for the UDH and the through axle remain corrosion free.
Yes, on these I spaced the NDS the 7mm as per the UDH insert. Purely so the rear end was symmetrical. Will be revusuting that though as it put the seat stay possibly too far out to mount the brake efficiently. It works for now though.
The snap ring hanger does not require the snap ring. Even with the axle removed and a heavy ass mtb derailleur installed - the hanger will not fall out.
Patents are purposefully left vague to draw lines around competitors. I know, because I have been involved in that process and have several stupid patents (not bike related).
There are already precedents that SRAM enforces its patents. They have to, otherwise, they lose their right to their patent.
Instead of guessing, Ill just put SRAM on the record and ask what is allowed and what isnât!
I donât think the claim matters. Based on the UDH website, SRAM believes they have a patent on the design, and that is enough for their lawyers to come after any dropout manufacturer or builders, no one is going to have the resources to defend the claim.
In the end, both sides filed documents with courts in Colorado and Illinois last Thursday saying they were dismissing claims and counterclaims, with no admission of liability by either and with each side to bear their own costs and attorneys fees. Industry titles are speculating that the costs, which are believed to have spiralled into the millions, simply became too high for either party to continue pursuing the matters.
In the narrow wide case, they had a pretty explicit patent, but that was not enough for the legal system to make a decision for either side It was ultimately decided by a game of financial chicken between the lawyers.
Again, I will reach out to SRAM directly to see whatâs up. This may not matter to the individual garage builder, but it matters to the community as a whole.
The irony of the âuniversalâ derailleur hanger is that it will result in a universal dropout interface. This dropout interface will become the standard, and derailleur hangers could be designed to be compatible it(and no longer identical to the original UDH). This could result in a better UDH(or UDH variants!).
For example an improved UDH could discard the fin feature, which may not be necessary. A small pin behind the hanger could instead limit rotation without a fin. This would allow the âimprovedâ universal derailleur derailleur hanger to be more compact, while still replaceable with the original UDH.
All that is really necessary is a universal dropout/derailleur hanger interface. If a standard interface is adopted then it does not matter what features the dropout or derailleur hangers have. They will be compatible.
@incepi welcome to the forum! That is a great point. Universal becomes âonlyâ very easily.
I have tried a few designs with the fin shaved off. It solves the SS issue, but IMO, the dropout was still too bulky due to the 20mm bore.
I realized if I was going through the trouble of shaving fins and creating a new âstandardâ, I might as well just accept the compromises and make it fully compliant!
If the ultimate objective is to eliminate derailleur hangers entirely, and replace them with a coaxial mount, then the UDH will only be necessary for making new frames compatible with old derailleurs. There is no guarantee that the coaxial mount standard will succeed, as other component manufacturers may not offer compatible derailleurs. Consumers may also reject the ânew standardâ mount. In that case the industry returns to existing with a variety of hangers, including the UDH.
