Volderke said:
The complexicity is to measure the improvement.
For sure some riders' position could be better, but how would Big Mig hold up with his equipment in these days? I would say he would be doing pretty well.
Not to mention that a lot of riders in 2013 still have lousy TT positions in terms of drag, regardless of how hard they go.
I would not dare to say that all those modern aero frames really have made an advantage. Same goes for the wheels, as early 90's wheels (e.g. Shamal + Gibli) were already pretty aero. Most advantage compared to 20-30 years ago is in frame stiffness, imho.
Aero wheels from the 90's (e.g. Campag Shamal) are closely equivalent in aerodynamic performance to today's offerings
in low yaw conditions, however improvements in wheel aerodynamic performance at the higher yaw angles more typical in road TTs have been obtained in more recent times.
There is an issue as already mentioned when comparing apples with oranges as far as bike frames go, since the rules have changed significantly over that time period.
Nevertheless, there are many professional riders who are not optimising their position and equipment choices in a W/m^2 sense. For some it's just not a priority, TT performance is not their primary job.
Position they can do something about to a degree, but equipment choice is more about what their sponsors require them to use than what's the best choice. Indeed what pros use is often a poor guide to what's optimal.
A classic example of that is aero helmet choice. Anyone that does regular aero testing knows that:
- not all aero helmets are equal in terms of aero performance (and there is quite sizeable performance difference between various models)
- no one aero helmet is the best choice for each individual
Hence when you look at what a pro team rides, the helmets used are often not the best option, and even if it is one of the better options, it likely won't be the best option for all the riders on the team.
There have also been a number of "marginal gains" in aero frame design (e.g. integrated brakes), and aerodynamics at the pointy end of performance is exactly about such marginal gains (despite the phrase having been hijacked as euphemism for more nefarious performance improvement measures).
End of the day, hard data on such items from the 1980s/90s will be difficult to come by such that sensible comparisons can be made.