An experiment from a few years back repeated in 2017 for a race in the park, Meppen, Germany.
A carbon 209 equipped with a carbon 24’’ front fork, 24 ‘’ front wheel with 24 aero-spokes, Ertro 571 rear wheel with 24 aero spokes and narrow fast high pressure tires.
The result is a beautiful rowingbike, a tiny bit faster than the regular 209 but very much less comfortable.
The more reclining position makes my back to hurt and the vibrations of the bike with the narrow tires are very uncomfortable.
The gain of speed is not much perhaps 1 or 1,5 km/h on a one hour time trial.