If a seat post clamp’s size is listed in English units, is it still going to fit OK on a frame designed for it’s metric counterpart? Will it need some extra muscle/grease to get it on there?
eg-1 1/8 inch seat post clamp on a 28.6mm OD neck of a frame.
Google says: “1.12500 in = 28.57500 millimeters”
The difference between 28.575 and 28.600 is about 0.09%
Let’s put this in perspective. Say you were driving from San Francisco to New York, and by some horrible error, you missed your destination by 0.09%.
You’d only be off by about two miles… more or less, you’d still be in New York.
Short answer: you’re fine to use the 1 1/8 clamp.