ljsmith
I just watched this on GCN.  I have always loved light wheels because they make me feel fast.  However GCN claim wheel weight doesn't matter.  Although this is based on simulations, and GCN often uses some questionable pseudo-science, I suspect there is at least some truth to what is being said here.  However I think for moutain biking where you are on the brakes a lot, and you can't really get aero wheels, the lighter wheels are probably better.  At the very least its an interesting watch.

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leggett24
Angular momentum makes aero king. It still feels counterintuitive to say rotational mass is a non factor in a climb though.
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mosinglespeeder
I call this myth...and pseudo science.

Just look at the PRO peloton, and yeah, that's why every racer out there is using wheels that weigh over 2kg....and tubulars that weigh more and.....yeah, that's just not what we see eh?

Plus, having ridden both, and raced, pulling the trainer wheels off and running light tubular carbon wheels buys speed faster and easier than anything else going out there

But an honest assessment and science has always revealed wheel/rotational inertia to be an exponentially most impressive force (IMHO) more than all other considerations on the bike if your looking for speed and improving performance
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leggett24
Rotational inertia is a big factor in acceleration but not at constant speeds. Pros go light because it takes less power to accelerate a light bike and less power to gain elevation on a light bike. The moment of inertia of the wheels only matters in changing speed. It's easier to speed up on lighter wheels and harder to slow down on heavier wheels. For the most part we all, especially me, try to avoid too much acceleration. I can't afford the matches anymore.
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Fett
I agree with most of above. Weight matters most when climbing and accelerating. At a constant speed and lesser elevation changes, aero and rolling resistance are the more important factors. 
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chas
Quote:
Just look at the PRO peloton, and yeah, that's why every racer out there is using wheels that weigh over 2kg....and tubulars that weigh more and.....yeah, that's just not what we see eh?


Actually it is changing.  Pros are switching from tubulars to tubeless because Its not Aero (for gravel) and its not weight so much as it is rolling resistance.

What struck me - a pro team was blind testing tires.  They all disliked the tubular tires and gravitated towards the heavier clinchers (GP5000 tubless style) because they were just faster.  Sure, they might be 100 grams heavier, but rolling resistance counts.

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mosinglespeeder
I would agree, I definitely notice it with speed changes/accelerations and climbing (although I am no climber)...BUT I would add another place I have noticed benefits of less wheel weight is toward the end of a long ride/race, when your coming in and keeping pace in a race or whatever and either hanging on or attacking, and when you have that 'little extra' its definitely easier to maintain and keep speed/break away with the lighter hoops....and however, don't get me wrong, I and we may well be adding in the benefits of aero with weight together because we are taking our subjective experience and trying to speak from the objective/scientific position....and I just don't have/keep data on this like the GCN cats up there
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ccand51997
Finally someone who explained why the rotation weight advantage is such a myth.  I've tried to tell people much the same thing and laughed when they said they know they can feel it.  And they can feel 'something' but that something is the quick spin-up with less stored inertia.  GCN has some odd stuff on its sight that can be laugh-able at times, but interviewing the Swiss stop guy was gold.  Doing the math tells you what you need.  
Here is a second opinion from another smart math-cyclist if you are interested:
http://biketechreview.com/reviews/wheels/63-wheel-performance
Willett does a similar thing and takes a ride file and applies the math to it with an even larger differential in weight but similar conclusions.  
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