With disc brakes, it’s still non-trivial to hit 6.8 kg in a fully kitted-out racing bicycle. You need to make some tough choices to get there.
Thankfully we’ve moved away from the weight obsession anyway, such that even pros care less about this than they used to. The new obsession is drag reduction, something that is complex enough that almost any claim can be supported by cherry-picking the evidence (modelling assumptions, wind-tunnel set-up, yaw angle, time versus speed versus power versus drag force saved over different distances, times, etc., etc. You can’t even get experts to agree on these things and yet Specialized – to pick the worst offender – is happy to boil down everything to a single figure of merit that fits in a clickbait title).
This new environment is a marketing windfall, and the American companies that excel at this haven’t been shy to hit us
with unlikely claims.I can’t point you to drag tests beyond the advertisements for the Propel Disc or Venge ViAS Disc. But from what I’ve read from reputable or knowledgeable sources – excluding the manufacturers’ propaganda – disc brakes have slightly more drag.
Kittel’s Venge ViAS Disc from last year
weighed 7.95 kg.