I want to see your data and your method.
In my blog post I have at least described method and sample sizes. I am convinced that I can replicate the results. And now I’m tempted to.
I will also go through the below, the “theory”, again for the umpteenth time:
Outdoors the lighter rider has an advantage in climbs. It is not as large as one would think and there are studies that show this. (I can’t quote references from memory but I can look it up and come back if you like.) Rather, the studies say, climbers excel at climbing through a combination of relatively low weight AND high VO2Max AND high recovery rate (they need all three). They deliberately and sadistically kill other riders uphill, that’s their only available game. TT pace uphill alone simply does not give enough advantage against the heavies. But yes, there is an advantage for lighter riders on average. Outdoors.
So why isn’t there an advantage in Zwift too? In general terms, outside of Zwift races, maybe there is. There should be, seeing as Zwift seems to use the “standard” model (there isn’t just one but probably something like this).
But then comes the W/kg cat system and destroys everything we thought we knew about cycling. In races you can’t take just any two cyclists and compare. You need to add the racing context. You need to look at the competitive end of each category, the podium takers, because nobody else will ever matter in the races.
What do they look like, the contenders? In Zwift they come in all shapes and sizes but they have exactly one thing in common. They can all produce a W/kg at or near the upper limit of their cat. (Actually, many of them can do better still - many are cruisers or at least have a small cruise potential they can utilize.)
So let’s take two cat C riders as an example, two contenders. They can both do 3.2 W/kg, on the flat and in a climb. If they couldn’t, then they wouldn’t be contenders. Someone else would who could would take the podium instead. They also can’t do more than 3.2 W/kg. Well, maybe they could when freeriding, but they can’t do that here or they would get a DQ. So they will both stay at 3.2 W/kg.
We also assume that they are both smart and experienced racers. They know to draft when possible and they can do it well. And now they are both participants in a race on Road to Sky.
Now, on the flat you say there is “some correlation” with weight on the flat. This is ridiculous. Any light participant in any group ride led by a heavy ride leader can attest to that. There is just not “some correlation”. There is a clear speed difference at the same W/kg and this I also shows in my trials. In group rides the leader is almost always in draft and the light participant will have to produce noticeably higher W/kg than the leader to keep up. Races are no different.
But what if the heavier racer is already at the 3.2 W/kg limit and in draft on the flat? Then the lighter rider will have to go above 3.2 W/kg to stay with him. But he is not allowed to! So how can he win in a theoretical super flat race with no changes in pace? He can’t, not without getting DQ’d. This has absolutely nothing to do with the physiology of the riders. This is all about the artificial W/kg rule set.
So on Road to Sky the heavier rider has an advantage in the approach. It can go either way. Either the heavier rider can hang with some sandbaggers while still not going over W/kg limits (the lighter rider couldn’t), so that he gets a head start in the climb, or he sits in the same group as the lighter rider but exerts less effort and is fresher when the climb starts.
But let’s forget about the approach. Let’s assume both start the race at the foot of AdZ, both equally fresh, both contenders in the sense that they can both keep 3.2 W/kg uphill, only with different weights. Now what will happen? Well… they will both start climbing at 3.2 W/kg. And keep at it. The heavier rider is faster at that effort on the flat, but what about at an 8% gradient?
They will be going at the same speed!
Well, to be correct, if you look at cycling models/Newtonian physics and only take the riders in isolation into consideration, the lighter rider will have an ever so small speed advantage (we’re talking less than a tenth of a kph). A minuscule speed advantage more than offset in the approach. But as @Aoi_Niigaki pointed out recently, you also have to add bike weight to the equation, which ruins everything for the lighter rider who has to carry a relatively higher bike weight compared to his body weight and Watts than the heavier rider. So the advantage is nullified. This is not opinion. This is physics. Don’t argue with me. Argue with Newton.
This is not to say that the heavier riders has a clear advantage uphill. He doesn’t. Both will climb at roughly the same speed. But the heavy rider is not disadvantaged.
So all in all the heavy riders who are contenders, who are actually in any position at all to win a race, are advantaged on the flat and not disadvantaged in climbs. The light contenders have no advantages at all. The only way to compete against heavier opposition is to produce higher W/kg, but if a light rider is already at the 3.2 W/kg limit then he is not allowed to because of an idiotic cat system that should never have existed. Who do you think comes out on top in races? It’s a nobrainer. It really is. Only people seem to have such a hard time grasping this.