The 2010 Tour de France winner's average was 39.585 kph.
Do you have a new, lower average winning speed in mind?
Now subtract the actual winner's average speed in the 1960 Tour de France from your number. BTW, that 1960 average winning speed was 37.210.
The difference left is your estimate of the difference that 50 years of improved bicycle technology has provided.
Yes. Thanks. Hugely well said. I wasn't trying to be serious, just saying that at my tiddly little level I find my newer bike easier (if not faster. My most frequent 40 kms, not much difference between steel/carbon "Best", lugged steel "ol'reliable" from 1990, and the Xootr folder. I just work the same, which is well short of the parameters at which techy differences would show a difference)
I'd love to be whupped by Fausto Coppi on a postie's bike with a full load of parcels