Hi,
I am probably missing something, but… - I have allotec c82 dropouts. How to align them? I thought that their bottom straight edge should be paralel to the line going to BB? But can’t find any document stating that I’m correct 
When I put a hanger in them aligned in this way - slots for the axle dont align, and it made me investigate it.
You have to look at the derailleur hanger specifications for the correct alignement.
Hi,
I might want to mill custom udh insert,
I know that it’s left-handed but what’s the outer thread pitch on the udh bolt?
If it’s a custom UDH insert just use whatever you want unless you intend to use the existing fixing bolt.
I just use an all alloy UDH hanger (IE not the sram co-molded plastic one) as a sacrificial holder. That way I know the width is perfect and I’m too poor to have a machine shop.
Yeah, it would be nice to make it compatible with the original bolt. From my measurements, it’s something around M17×2.0, but I need to test it out
I’ll try to remember to measure one when I get home as a validation for you. Still travelling from the show.
Actually, it doesn’t make much sense. I could ignore UDH and design my own solution, given how they’ve made it. Reusing the bolt doesn’t change much… I’m trying to avoid creating new standards and to limit the number of parts as much as possible. Solutions like Surly’s “DUH” might actually be the closest to be the simplest (the right side)
Unfortunately, if I want to use UDH, I’ll need to add some kind of lock ring to keep the hanger in position.
SRAM didn’t think about sliding dropouts at all when designing it.
Allotec makes UDH inserts for their sliding dropouts. These are basically copies of the Paragon design except that the bolt distance is 44mm vs 30mm.
They did it in a weird way that puts the UDH inside the right slider, so this pushes the right dropout out by 10mm. I don’t think there is a good alternative unless you radically redesign the dropout.
Personally I don’t think it’s worth it and prefer the standard hanger inserts.
You could make Item 1 wider so when the bolt, item 8, is done up it clamps the whole shebang. I do that on my personal frames as I’ll will most likely never use Transmission (no hate, just prefer Shimano) . I like the hanger locked down. If I ever use Sram I can just trim it up to get back to spec.
Just did this yesterday. I used an M4 bolt to limit the hanger’s angle and keep the part as thin as possible. Just curious, why do you keep it only for your frames? Is it because of cost or something else?
I don’t think the limiter bolt or tab (M4 in your design) is really that crucial on a UDH dropout. Once you tighten the insert in place it won’t pivot. It helps define the angle, but I don’t think it’s worth adding a bunch of material and design work.
Well, I’m not sure if it’s worth making sliding dropouts compatible with UDH in the end. If I need to make an additional part anyway, I could make the whole insert as a single part and design it better. There isn’t much sense in using a derailleur on sliding dropouts anyway, as you would have to change the chain length and set up the derailleur every time for it to work properly.
The accessible replacement argument also doesn’t seem to work if there has to be an additional part anyway.
So why am I even trying? Haha.
Surly’s solution with interchangeable interface between udh and sliding is probably the best for this but is it worth complicating the design and user experience that much… not sure.
I would just make a mark for the alignment and not bother with a bolt.
I think it’s a worthy endeavor to make some good UDH slider dropouts, or at least a clean thru axle slider. It’s on my list to do. I think Prova made a really nice looking set at one point.
That’s almost identical to what I designed and had printed for my latest personal hardtail.
It has been flawless.
Details here:
For customer frames I stick to the SRAM specification so they can use the Transmission derailleurs if that’s their choice. It’s only 0.5mm of material which is easy to remove from the printed frame ends.
On my frame ends I don’t use the post to create the forward rotation stop. I’ve modelled in a small step the front edge of the derailleur stops against. I gave a little printed in stop for the rear rotation on normally ( this is the DH frame end. Will only ever have Saint on it so locked hanger)
None of what I’m showing really helps with a solution to sliding UDH
Jester frame end below
Really nice design. Any issues with the dropouts slipping or creaking?
Zero problems with slipping or noise.
I’ve got forward-facing M5 tensioner grub screws that keeps the assembly from sliding forward even if other parts of the assembly are loose.
That plus the combined holding power from the torqued hanger, M5 bolt holding the front of the brake mount in place, plus the torque on the thru-axle keeps it all nice and snug.
