For some reason the C-Dale sizing guide for a carbon Synapse suggests a 54 which is for 5’-7” to 5’-11”, where the 56 is for 5’-9” to 6’-1”, so I’m not understanding their logic. I’m 5’9” with a 83cm inseam, but long torso and am perfect on my Topstone with a 56 ETT. I can’t see you in a 54.

As well, I would not get mechanical disc, I would pay more for hydraulic. Worth the money and really very little maintanence other than disc pads. My 2019 has only been bled once, has never needed fluid changes.