Hello.
Id like to apologize right now. I know there are many many posts regarding this type of situation. But non specific to me! 
So I am going to throw it out there.
I am looking at buying a 56cm felt IA. 2020
I am in Thailand, and it is quite difficult to find larger size bikes.
I am 178cm tall, and inseam is around 85cm.
I normally ride a 54cm. I’ve only had cervelos. R3 and P5. Both have been quite nice.
I’m sick and tired if waiting for a good trip bike at a good price that is a 54.
I broke my tib, and tore my MCL and ACL a few months ago, and I am dying to get back on a bike, for fitness/hobbies/rehab.
I know the 56 is a little bit for me. I believe the threshold it 180 and upwards. But I know that most modern tri bikes had adjustable front ends.
Am I wasting my time and money taking this bike?
My other option is a 51 felt IA. And I know it’s easier to make a small bike larger then a large bike smaller, but my height is 6cm off the 51 threshold, but only 2cm from the 56cm.
Any help or advice all you guys could throw my way would be much appreciated. I am hoping there is someone out there who is or has been in a very similar situation to me.
Thanks in advance. Liam