Pls choose the EU SIZE according to the Internal Length of Shoes that fit your Foot Length.
The Internal Length usually be Little Bigger than your Foot Length.
Your foot length is 27.5cm.Then you should choose that size of inter length is 28cm(EU 44).
And if your foot width is larger than usual,then you can choose Internal length 28.5cm (EU45).
Road Bike Shoes 271.6g/pcs( EU Size 42)