Sat on a 50 at one of my usual shops and it felt a bit small off the bat. They didn't have a SS in 52 but did have a left over 2015 52 CAAD10 Ultegra 3(in team colors no less) and I didn't feel stretched out on it at all, felt pretty good - dare I say better than my current ride - for the few laps around the lot I did. I need to go back with pedals and kit and take it on a proper ride.