I think the 50mm aero wheels made me a bit faster...
Usually do a long mixed ride around san francisco hills to the golden gate bridge and get 12mph or so due to some really steep gradients. I decided to try some flats.
I got 19mph average but only for about 7 miles..the longest flat I know that is enjoyable to ride. There were a few hills and some down hills, and stop lights/stop signs too but mostly flat. I felt like I was pushing myself, but there were stretches where I was admittedly coasting. If I was going 23-25mph on the flat, I would allow myself to coast until it would go back to 19 then pick it up again. Not sure how long I could keep it up. i think I could of gone 20 miles total at that pace possibly but too out of shape to try. Think next time I'll just do laps on that flat area and see if I can keep up the 19mph pace for longer. I'm a bit upright with a very tall steerer tube. I think when I drop the bars 20mm soon I'll see a slight improvement.
I do wonder if the aero 50mm carbon wheels are helping me. I read an article where test showed that aero wheels increased speed about 1.2mph compared to regular spoked wheels even when at under 20mph. That's a significant gain if true. I do feel faster on these 50mm carbon wheels versus the ksyrium sls that I got rid of.