Originally Posted by
CliffordK
Anyway, let me know
So there was an Argon 18 hanger on eBay that looked like it might work, but the supplier couldn't be bothered giving me any info on it.
After a while I caved in and gambled on it, and it fit perfectly. Countersunk lower bolt, upper one a button head through a curved slot for angle adjustment, very neat. And the main thing is, it's beefy billet, so I was able to use the Sensah fd without fear of breaking the hanger again.
So yeah, for posterity: Specialized Tarmac from about 2008, 15mm bolt centres on the front derailleur hanger (the type with the mounting bolts behind the fd mount), Specialized dealers couldn't help, but Argon18 hanger worked.