Originally Posted by genejockey

AX has some cool features. Shimano did really think outside the box in a number of places. First, they made some of the first aero brake levers, back in 1981, when everything else was exposed cables. They moved the shift levers from the sides of the downtube to the center, mounted on a single post. The Dyna Drive cranks and pedals placed the pedal platform BELOW the pedal spindle, with the effect of lowering the rider as much as a cm, both for aerodynamics AND for biomechanics*. They made clear plastic dustcovers for the headset, presumably for aerodynamics.

There were frames built in Japan by Tsunoda and maybe others with "aero" tubing that were designed to be used with AX, and rebranded as various other makes. I think Lotus and maybe Miyata sold them. The seat tube had a teardrop cross section, IIRC.

It didn't sell, probably because 1) Shimano was pretty new to most riders/racers at the time and hadn't built up a following, and 2) it wouldn't work on most bikes because of a few features like the shifters I mentioned and how the cables ran, and 3) it was kinda weird and honestly not all that much more aerodynamic. A complete, original aero frame with full AX might be fun to own, if you could get it cheap enough.

*The crankset and pedals actually predate the AX groupset, having been introduced a year earlier as part of the Dura Ace EX group. The huge pedal holes in the crank were because that's where the bearings for the pedals were.