Hi Boris,
since no one answered your question yet I'll do my best. Please forgive me if I'm wrong here but you seem to do some guesswork concerning the size of that AL DH bolt. Why don't you ask Proprain directly which size allen key you need to install a new hanger?
Their hotline should work or just send an email.
Once that's solved you can start coming up with solutions. A very simple one would be to pack the correct size allen key along with your multitool. Thats a lot cheaper than buying a second hanger for spare parts if you ask me.
I hope I was able to help. Please share your solution with us once you've managed to come up with one.
Hey Twmtb,
Thanks for answering.
I don't want to ask Propain for two reasons - because I know how much work they have (way more important than my question) and because I will (hopefully) find soon what the exact size is.
Packing an extra wrench will be the solution at the beginning, at least until I make some modifications. You are totally right - I am guessing about the size of the key. But looking at photos and knowing that the axle is M12, I don't see how the wrench key can be smaller than 15mm having in mind that nut that holds the hanger has even bigger than M12 thread. And a full size 15mm wrench key is something that is not light and you don't want to carry on long trips in your backpack. An option might be to search for some small wrench key.
As for the price of the new CF hanger - I will buy it, take the bolt and sell the hanger it self for lower price (like 15 EUR). Or another option is to buy the SRAM UDH as it can be found for as little as 10 EUR. The problem with the Sram one is that I don't know if the thread pitch is the same as the Propain AL one. My biggest concern is if it will actually work. But buying a second hanger will fix at least one thing for me - the ugly hole thats left with the AL frames.
In any case I will write when I have done something.