Shopping in person will let you try before You Buy.
Why is the steerer tube measured in inches, and the handle bar diameter in mm?
It Just Is , get used to it! .. Its a Tube and tube standards are Inches and Fractions ..
but metric equivalencies seem to be how the Bike Biz speaks 31.8 is almost 1.25" ( 1.25196850394 )
There was a French Metric tube spec for a while , but they Lost out in the market place
and now buying a french frame creates multiple Problems .. 25 vs 25.4 and so forth.
They wanted the 0 Prime Meridian to be Paris , but the British Navy was Dominant even 300 years ago
so it has been Greewnwich Mean Time .. England where the Prime Meridian is for Time and Navigation.