Here's some laps I did at 230w at an outdoor velodrome, on my road race bike with normal kit and helmet, in the drops.

It was not a completely calm day, but the wind wasn't a major factor. The average speed came out to 22.9mph but I would expect that was a bit high due to wheel circumference issues. Bet on 22.5

I do have a rather small frontal area though. Some folks have big shoulders that are just impossible to hide. I am not one of them. I also have a pretty aggressive position on the road bike.



the faster part (where my speed is sitting above the average line) is around 250w and 23.5mph indicated (actual maybe 23.2)

It would not surprise me at all if a larger rider would be at 21mph for the same power for the overall 12 minutes, since I have large teammates who show similar numbers. It also would not surprise me if a rider with a higher handlebar position would have similar numbers to the larger rider.