I don't think it is the calipers that cause the added drag, it is the discs themselves, particularly when they are on the sheltered side f the bike vs wind direction.

That said, they didn't fill in the seat cluster (which seems to be a current "best practice") and the down tube cable routing is infuriating.

Through axles: I love it. Totally unnecessary, I know, but I'd like to have them on every bike I own.

Saw this pic of a new aero disc brake road bike on bikerumor. Cool looking bike, but that saddle to bar drop looks kinda crazy.

Not sure (have not seen any data), but I wonder if the shimano direct mount disc brake standard (used on this new bike) significantly reduces aero drag vs conventionally-mounted disc brakes. Another interesting thing, the zipp decals on the wheels go almost right to the edge of the rims ...

Curious, what do you see as the issue with the downtube cables?

For the rear maybe. But for the front, a through axle add considerable security, as the forces generated by a front disc caliper try to force the wheel out of the fork dropouts.

There coming.

All I see is an oxymoron.

Stop me if I'm going off-topic here, but I'm wondering if disc brakes can eventually be more aero than rim brakes. My thought is that there could be gains by using a smaller diameter, solid disc. Another area could be the rim itself. Since heat management of a brake surface near the bead of the tire is no longer a concern, perhaps that area could now be thinner or made to integrate better with the tire to make it more aero. I dunno - just kind of thinking out loud...

On another tangent, in-hub drum brakes seem to have aerodynamic potential in theory, but implementation would be another story...

I have an idea...what if we make the braking disc even LARGER?...and then, for the best aerodynamics, integrate it into the rim?

Think about it...then the calipers could be centrally located within the frames for even better aero, and the spokes could be made lighter since they no longer have to transfer the braking loads to the tire (not to mention the forks and frames could be lighter since less reinforcement is needed)...and, since the braking diameter can be SO large (leading to massive braking torque) the braking surface could be made lighter by switching from steel to a lighter aluminum alloy...possibly with a machined and hard coated surface for better all-weather performance.

Boy...if only we could skip this current awkward separate braking disc phase and proceed directly to THAT technologically advanced stage...if only someone made something like THAT...

I have an idea...what if we make the braking disc even LARGER?...and then, for the best aerodynamics, integrate it into the rim?

Think about it...then the calipers could be centrally located within the frames for even better aero, and the spokes could be made lighter since they no longer have to transfer the braking loads to the tire (not to mention the forks and frames could be lighter since less reinforcement is needed)...and, since the braking diameter can be SO large (leading to massive braking torque) the braking surface could be made lighter by switching from steel to a lighter aluminum alloy...possibly with a machined and hard coated surface for better all-weather performance.

Boy...if only we could skip this current awkward separate braking disc phase and proceed directly to THAT technologically advanced stage...if only someone made something like THAT...

Of course, totally agree, with current technology with AL rims (not carbon rims), the right caliper brakes with the right pads are fine, and the best solution currently available for TT and tri.

That said, for rain or wet weather, the story changes completely. I've put in a lot of miles in the rain with caliper brakes and also (mechanical) disc brakes. And at the current technology, there is no comparison. Disc brakes, even with all of their drawbacks, leave even the best caliper brakes in the dust. And by a huge margin.