My regular ride is a Kuota Kredo from 2005 with Chorus 10. Sizing keeps changing over the years. But now that you say it, I'll have to check as I've owned it that long and haven't really thought about it much. It could be a 50. The Cannondale in the pic is a bit small for me but still comfortable. And it is hard to say if I could ride it all day or not since I have a meniscus tear in my knee and can't ride it all out although it felt OK doing the ride that I did. And it is a woman's frame so it is a short top tube. I think the seat is at the high end of where you'd want to be though. I did a good job on the build though if I have to say so myself. No creaks, clicks, shifts perfectly both front and back, dead silent. It's been on 3 rides and the tape is already dirty.