Originally Posted by
merlinextraligh
this would be true without UCI weight limits.
But with a mandated minimum 14.9lbs weight, you can build a disc brake at the limit.
So there's no weight penalty for a UCI legal disc brake bike.
Not how it works. Regardless of the weight limit, you always attempt to shed rotating mass, even if you have to add weight to the rest of the bike. You can add useful weight by making the frame more 'aero'.
Besides, my bikes are not limited to UCI weight limits, nor do I suspect are the bikes of any of the posters here. Why would I want to add an anchor to my bling carbon bike with a pound of unnecessary weight? That is like converting a $8k road bike to a $4k road bike.
Second downside of road discs: the stigma when you show up on a group ride; it screams: 'newb'. Lessee, two such riders showed up on our last group ride. One got ejected off the front of his bike at the first hard stop. The second disappeared on the first climb.