disk vs. rim brakes - the science
(Great hearing the variety of opinions here!)
You can't deny the laws of physics. Disk rotors add rotating weight to the wheel, which reduces acceleration,
requiring more effort to go fast. Although it is near the axle, where the effect is smaller.
On the other hand, if you compensated by using lighter rims, you might end up with a faster wheel!
But I would want a guarantee that the rim really is lighter, and "not suitable for caliper breaks" printed right on the rim itself!
I bet there's a lot of money and commercial interests involved here! Brakes don't do anything to make a bike faster, there function is to stop a bike. But I will buy them if I'm guaranteed my rims are lighter!