If it was very simple, then so many in this thread wouldn't be wrong. CdA matters as long as you're moving forward. On a 3% gradient, if rider A weighs 70 kilos and puts out 280w with a CdA of 0.3, they will travel at 28.2 kph. If Rider B weighs 70kg and puts out 265w with a CdA 0.25, then they will also travel at 28.2 kph. Obviously this diminishes as the gradient gets steeper but for many, 3% grade can be considered uphill, even if moderate.
Yes. I’m a light rider with a low absolute power. I have a hard time riding against heavier and more powerful riders on shallower grades, because I lack the absolute power needed to overcome wind resistance, even when I’m drafting behind them. Once the road kicks up I leave them in the dust. As a small rider I also do poorly when climbing with a headwind. Again, I lack the absolute power needed to overcome the wind resistance. A heavier and more powerful rider is more likely to do better on a windy climb than a lighter and less powerful rider. I do very well on a steep climb with a tailwind. When the aero drag is zero then my superior power to weight ratio really shines.RyanH wrote:If it was very simple, then so many in this thread wouldn't be wrong. CdA matters as long as you're moving forward. On a 3% gradient, if rider A weighs 70 kilos and puts out 280w with a CdA of 0.3, they will travel at 28.2 kph. If Rider B weighs 70kg and puts out 265w with a CdA 0.25, then they will also travel at 28.2 kph. Obviously this diminishes as the gradient gets steeper but for many, 3% grade can be considered uphill, even if moderate.
Sent from my iPhone using Tapatalk
exactly lol this guy has no idea what he is talking about.
My 20 minute power is 360w. I weigh 67kg. My Watts per kilo is pretty strong, but unless I am dealing with a decent grade I am not at a huge advantage compared to guys that can put out 400w which is typical once you get to cat 1 and 2
And if someone is matching your watts per kilo, whoever is doing more actual wattage is probably going faster.
Watts/kg or Watts/CdA matter to a certain degree, but even in a 3km or 4km pursuit on a closed velodrome things like pacing, the line you ride and your technique still influence the outcome (notice I didn't once mention watts, kg or CdA). There are plenty of different ways to 'average' 300w, or 5w/kg or whatever w/Cda for an effort. By definition there's only 1 fastest way.
Can I just add that, 'simple maths' is almost surely wrong. Especially when the systems we're talking about are 'unstable'. In fact, I wouldn't even call it maths, it's more like 'a rough guess at basic physics'.
Ok, I felt like I needed to get that rant off my chest, please continue
Disclosure: I'm sponsored by Velocite, but I do give my honest opinion about them (I'm endorsed to race their bikes, not say nice things about them)
If I race with you I'd lose on the uphills, flats, and downhills. I'm old and slow. But that's beside the point. There's a group that I ride with occasionally that consists of heavy riders. They are probably closer to 200lbs or 90kg. They are more powerful in absolute watts but have subpar W/KG than me due to their high weight. Although they have lower W/KG than me they can still give me trouble on shallow climbs when the speed is high. That's because when the speed is high I'm at a disadvantage in terms of W/CdA. And even with my higher W/KG I still lose on shallow grades because of my W/CdA disadvantage. That's why the gradient level is very important when we talk about W/KG because the gradient also determines how fast one is moving and hence how much air resistance there is.
Cannondale Supersix 2008 (weight: 7.3kg)
B'twin Triban 540 (in bits)
Vitus "Benotto" 979 (weight: )
- Similar Topics
- Last post
- 17 Replies
- 2508 Views
Last post by Colt501
Sun Mar 25, 2018 4:55 pm
- 9 Replies
- 997 Views
Last post by wiRIDEfast
Tue Mar 13, 2018 9:30 pm
- 3 Replies
- 572 Views
Last post by Marin
Thu Dec 28, 2017 11:27 am
- 6 Replies
- 685 Views
Last post by dino0204
Sun Mar 11, 2018 11:06 am
- 20 Replies
- 2149 Views
Last post by jfranci3
Sun Jan 07, 2018 3:03 am