Nate's ideas about W/kg and size

Point being descending like that is also considered a feat in cycling. All this talk of weight reminds me of a few posts on reddit a couple of years ago.

TLDR: lighter riders win Lombardia, heavier riders win Roubaix and lighter sprinter types win MSR…well duh

Edit: I realise none of this really addresses the W side of the equation but interesting anyway.


Add fuel into the mix. It has to be harder to fuel a higher wattage rider over multiple cat 1s and the final HC climb. And to have that fuel be used quickly enough at the higher burn rate.

Of course these heavier, higher wattage riders train all their systems for this but fuelling has to have a smaller margin of error for them than smaller, lower wattage riders. It at least seems like one factor for long and multiple days in the mountains.


That’s sort of a different question though, isnt it? Caloric expenditure and calorie consumption is not really related to the question of watt/kg.

Well it isn’t if you don’t think about just FTP (w/kg) and starting thinking about power curves more broadly. Being able to fuel adequately surely has an impact on the watts in the power curve at 2hr+ durations.

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Oh sure of course…it’s just we’re then talking about just being fast in general…not how physics affects humans going up hills on bikes.

watts and kgs are the only things that truly matter if you’re just pedaling (ie…taking skill out of the equation). Everything else …fueling, nutrition, training, sleep, aligning the stars, etc, works to change either the watts or the kgs.

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Its widely mentioned that fuelling is a big factor for big engines going long. The likes of ganna burn way more carbs than the smaller riders and the ability to absorb carbs doesnt scale as much as power.

I don’t know if anyone is asserting that a higher BMI correlates to better performance. I think the (perhaps unstated?) assumption is that weight is correlated to height and that the riders have roughly the same body composition.

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It’s hard to argue that for the same w/kg the heavier rider is going to be faster. But of course the best climbers in grand tours are pretty light guys….never 180+ pounders…so theory and reality are not in agreement.


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The problem is the assumptions… sure if you hold W/kg constant, the larger rider has the advantage… but… only very light riders going to achieve extremely high W/kg… I’d imagine you’d be pretty hard pressed to find very many 200 pounders pushing 5+W/kg.


In the real world, a lighter rider has an advantage over a heavier rider with equal watts/kg in terms of FTP because:

  1. super steep hills are about watts/kg above FTP
  2. the lighter rider will almost always have better watts/kg above FTP

That said, in theoretical scenario in which watts/kg is equal across the power curve, the heavier rider will always win. But this is not realistic in terms of physiology, in my opinion.


I’m not sure W/Cda is correct. From my tri days, it was usually thought that a larger rider has a higher cda (or needs to work harder to achieve a certain cda).

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It is correct. Larger riders have higher cdas but tend to have higher watts per unit cda. Hence why they tend to be better on flat time trials. Of course, that’s not a hard and fast rule, you get small riders like Remco who are very aero dynamic - but typically a large rider with the same w/kg as a smaller rider will have higher watts/cda.

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I don’t think that’s the case. Above ftp muscle’s relatively more important. MVDP and Van Aert are probably relatively better at shorter efforts. (Note whether you can go above ftp depends more on the climb length than than the steepness).

Probably what you’re seeing the real world is a smaller rider with better power to weight and than the larger rider, but they only have an advatage from this on steeper grades.

Theory and reality are in agreement - the 180 pounders have lower watts/kg

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Yup, smaller people do tend to have better power/strength to weight across most activities. But just on average, plenty big guys have higher watts kg than small guys - I’m 67kg but I’m never beating wout van aert up a hill! (Nate’s points about two people with equal watts kg.)

On the flat watts/cda wins. This typically favours those with the higher pure watts, but not necessarily.

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Your muscle mass is correlated with your body ‘frame’, and that is constant regardless of body fat%. Watts are definetly correlated with body ‘frame’ (bigger frame → bigger watts).

Muscle mass is not the limiting factor, FTP and VO2max are limited by oxygen uptake, the reason that bigger( really taller riders) can have a higher FTP is that there is more room inside their chest for heart and lungs.

This. Most people getting this wrong are mixing up absolute power and w/kg. The question is talking about w/kg so the gradient is irreleant. At same w/kg the heavier rider will go faster up the climb due to higher absolute power, counterintuitively. Of course they will have to put out far more power on steeper gradients.

It’s practically impossible as a big rider to reach the w/kg level of the likes of Vingegaard at sub-60kg; you’d have to have an FTP of well over 500w at 80kg. Even if you reach that level, eating enough to fuel that incredible amount of work is near impossible over the course of a mountain stage with multiple climbs.


Is this correct? Ventilation volume and “lung size” could have a minor impact, I would think it is rather oxygen-carrying capacity and delivery to the tissue, and oxygen use at the tissue.

This was mentioned earlier in the thread, too. On a hot or warm day a smaller rider would be able to sustain a harder effort for longer due to better cooling. Broadly, heat generation is a function of mass and cooling is a function of surface area. Smaller riders are going to have a better surface area : mass ratio, at least for a mild to hot race.