How far above the head tube does a typical IRO threadless steerer extend? I'm planning my BFFGSS group buy build. I think I'll start with the bars mounted high. My current stable of bikes has 1 inch threaded forks and not so tall stems. I have replaced the drop bars on both my current road bikes with moustache bars because I can't reach the drops comfortably. So, I'm thinking I'll try drop bars again. This time with the stem mounted high. I'll experiment with different heights for a while by changing the stack configuration. I want to know how much steerer tube extends above the head tube so I know how many stack spacers to buy.