Originally Posted by Clem von Jones

Your touring bike is a converted mountain bike with 26" wheels I assume. I think 21" measuring from the center of the BB to the center of the top tube is probably a bit large but unfortunately I don't know what the ideal frame size is for you. Since it's being used for touring you could set it up for a more aero stretched-out position with lowered bars and perhaps it would still fit okay. With a frame on the too-big side you might have difficultly getting the bar low enough for a roadie position. I am biased towards a roadie position even on my mtb but I'm pretty tall and thin so that works for me.