Or, buy a seat tube gauge. Admittedly, it’s not something you’ll use every day and it’s not much use for anything else but it will give you the definitive size. Alternatively, take your frame to a bike shop and ask them to measure it using theirs and play nice by buying your seatpost from them.
Or, buy a seat tube gauge. Admittedly, it’s not something you’ll use every day and it’s not much use for anything else but it will give you the definitive size. Alternatively, take your frame to a bike shop and ask them to measure it using theirs and play nice by buying your seatpost from them.