Headset Frame Cup Standards
 

Measuring my inventory of frames and headsets to match up some future builds and looking for advice on mixing ISO and Italian frame cups.

According to Mr. Brown's cribsheet, ISO frame cup diameter is 30.0mm while Italian is 30.2mm. 0.2mm is less than some measurement variances I get so I'm assuming I can interchange these without consequence. What say ye?

Sheldon Brown's Bicycle Headset Dimension Crib Sheet