700c is not the same as 27, but they are very close. 27 in is 630mm and 700C is 622 which will explain the tightness you are getting. How wide are the rims and what size size tire are you running?
__________________
Brian | 2023 Trek Domane SLR 7 AXS | 2023 Trek CheckPoint SL 7 AXS | 2016 Trek Emonda ALR | 2022 Trek FX Sport 5
you should learn to embrace change, and mock it's failings every step of the way.