Originally Posted by
FBinNY
Until fairly recently Campagnolo RDs used a 10mm x 26tpi thread.
Originally Posted by
jimmuller
And what did the rest of world use? That is the question.
The rest of the world used 10mm x 1mm which would be 25.4tpi. Very close, but not quite the same. Over the short depth of the derailleur hanger, it works ok.