Also worth noting that the increase in pro racing speed has been fairly linear since the 1920s. Even during times when bicycle technology has gone essentially unchanged, speeds still increased at about the same rate. Of course, the nature of wind resistance tells us that the 0.7 MPH increase from the 90s to the 2000s was a lot more significant than the 1.1 MPH increase from the 50s to the 60s, so I don't believe that bicycle technology has had no impact whatsoever. It's just that that impact is nowhere near what some people seem to think.