Biking Target Speeds On a road bike what is a good target solo speed for someone who wants to be a better than average cyclist?
Like is there a certain speed where you know as a cyclist you are doing pretty good like 20 MPH+ for an extended period of time?
What is the speed and duration in time/distance one would need to be able to sustain in order to consider semi-pro racing (male rider)?
I agree with Criggie's answer, but there's another way to look at it. Speed is mostly a function of power output. And you can quantify a cyclist's fitness in terms of their power-to-weight ratio, that is, W/kg.
This article shows what cyclists of different levels can produce in terms of W/kg, how long they can maintain different levels of output, etc. There's a lot there.
You can take that information and plug it into this calculator to estimate speed based on power and other conditions. You'll note that it takes a lot of additional power to go just a little faster.