Originally Posted by
slcbob
That's the fallacy. Cobbles don't favor a good rider who was lucky. They reward a great rider who delivers and punish those who take it easy. Sure, there's some chance on the margins, but it's amazing how much skill and effort can mitigate the impact of luck, if not eliminate it. Race to the entry point, stay at the front, power through, and it's amazing how you're rewarded. Don't do that and roll the dice. The cobbles raise the stakes on both ends of that, and they alter the kind of rider who is best prepared to step up.
Cross-winds do the same thing. Should we stay off drafty parcours? How dare they ride through the Camargue? !!
I think it was GCN I heard that cobbles favor big and heavy riders and really punish small and light riders. All presenters seem to unanimously agree on it.
As a light rider myself at 127 lbs, I definitely struggle on cobble and worse on cobbled climbs. The proportion of "sprung" vs "unsprung" weight favors heavier riders because the bikes essentially weigh the same regardless of rider weight and makes the % unsprung weight (the bike) less for heavy riders and less unsprung weight by % makes you more efficient efficient over rough surfaces.
Additionally, the bike has greater tendency to flex more under a heavy rider and that helps soak some of the bumps and makes the ride smoother under the pedals. One way this can be fixed for light riders is through full suspension with travel limiter and if possible, undamped to avoid losses as much as possible. Most likely with elastomers.
From own experience as a light rider, it isn't being jarred at the seat that is the problem but getting your feet jarred by the bumps through the pedals. So it makes little difference whether you're sat down or standing and having seat suspension won't improve power output on cobble. Seat suspension only improves comfort at the saddle but does not isolate your feet from the bumps which is more important to maintain consistent power output.
I was able to try a friend's Domane with isospeed and vs my aluminum "tank". The more flexible structure and supple tires made a huge difference to me and really helped to maintain speed over rough sections in a climb. On my aluminum tank, I'd slow down over the rough sections in a climb. If I didn't slowed down, I'd be hitting zone 5 effort which is crazy.
Perhaps, if everyone used full suspension bikes on cobble stages, it will help light riders a bit. However, the % unsprung mass for heavy riders would still be lower and favor them. Unless of course, the stage has plenty of long and steep sections, that might tip the favor back to light riders.