It's a silly situation.
It's a silly situation.
If 2 riders have a weight difference of 20 pounds and both race at the same level...They end up at the finish line at the same time. Does that mean that the lighter rider would be using a bike that is 20 pounds heavier... I know this sounds ridiculous but you stated that "all weight is the same in regards to climbing".. I am obviously exagerating here to make a point.
And just to recap (again), aside from the obvious exception about that which rotates, weight is weight. Ten lbs. of non-rotating weight, regardless of origin, has the same effect.
Upon rereading I see that OP was asking a somewhat different question than I answered. He was asking if two riders of identical abilities, one 20 lb lighter than the other, arrive at the finish line together, does that mean the lighter one was riding a 20 lb heavier bike? Who knows why one did better than the other. Small differences in weight give small differences in resistance to acceleration and climbing. Larger differences in weight would result in larger differences in acceleration and climbing speed. But to say that weight must make up differences between identical riders is a far stretch. There is aero both of the bikes and the bodies, there is technique and how it is applied on any given day. There is hydration or the lack thereof, and on and on. I think OP has good answers to his good questions and no real answers to his bizarre questions. IMO, that is how it should be.
You really need to ride a sub 14lb bike to appreciate the difference. Performance metrics are meaningless. I have 1 of my bikes down to 13.05lbs, ready to ride, and it's a blast, especially with the local hilly terrain. Makes my 17lb Roubaix feel like a lead sled.
You had stated that total weight (Rider and bike) was what mattered (given the fact that rotational weigh is of utmost importance). The point I was trying to make was that if that statement was correct than a rider 20 points heavier riding a bike 20 pounds lighter..given the same ability, aerodynamics etc.... would end up together at the finish line with a rider 20 pounds lighter with a bike 20 pounds heavier.. Yes. it is an exaggeration but the principle is the same.
Losing 3 pounds of body weight or losing 3 pounds of bike weight (assuming non rotational) has the same effect on the effort you have to expend.