Cannondale Synapse rear disk brake adaptor

carl_p Posts: 989
I've recently acquired a 2017 Synapse frame that I'm about to build up. It's my first disk build so not 'expert'. I'm planning on using TRP Spyre mechanical callipers so I can retain the Ultegra 6800 shifters I have and keep the cost down. The front brake doesn't look as though it will be a problem as the hole spacing 75mm matches the TRP post mount. The rear brake however has a strange hole spacing, around 10cm and looks as though it will need some form of adaptor to match the TRP fitment.

Can any Synapse/Cannondale owners advise me on what adaptor I need and provide a photo/part no? Would be much appreciated.
Specialized Venge S Works
Cannondale Synapse
Enigma Etape
Genesis Flyer Single Speed

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