I find it helpful to have a set of digital calipers, especially when building up old frames. I had the same issue with my recent Hardrock build but just took several measurements of inside the seat tube and took the average.
@Haggis started
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I find it helpful to have a set of digital calipers, especially when building up old frames. I had the same issue with my recent Hardrock build but just took several measurements of inside the seat tube and took the average.