I was wondering if someone could help me with the geometry of a two drum surface winder. I am trying to calculate diameter of the roll using the height of the Rider Roll. I know the diameter of the two drums. I know the distance between the two drums. I know the distance from the top of the Rider Roll to the surface of the roll. I have calculated this before but using the height of the core shaft. That is pretty easy. My problem here is that I keep ending up with two unknowns versus one. Has anyone done this before and how? Thanks.