I'm guessing he was confused about the percentage basis part. I'm no aero geek, but my understanding is if you had two identical riders with identical overall cda, the one who is slower will save more time (since they are on course longer) but the percentage would be equal. Would it not?

It was my understanding, which is limited since I have only been into the sport 3 seasons and just started thinking about aero this year, that slower riders DO benefit from things like an aero helmet more so than fast riders, in over all time differential.

Not that I would say equipment is MORE important for slow vs fast guys. But slow guys would get a bigger jump in TIME right?

If you double your speed, you triple the wind resistance, e.g. someone riding 14mpg only has 1/3 the drag to overcome compared to someone going 28mph. Since aero bikes, helmets, skinsuits, wheels, are all designed to decrease drag, the more drag you generate, the more benefits you will derive. To get the same overall drag reduction benefit, the 14mph rider would have to ride three times as long as someone going 28mph.

http://www.cervelo.com/en/engineering/thinking-and-processes/slow-vs-fast-riders.html

He is actually correct
http://www.cervelo.com/...-vs-fast-riders.html

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I think if you do the maths he is actually wrong. he saves more overall time, but as a percentage basis, it is actually a bit less savings. just look at the link you included and calc the % saving for the two.

fast = 86 sec in 30 min
slow = 107 sec in 40 min

for same %, slow needs to save 114.67 sec, which he does not

Technically, the guy was NOT correct. For example, in the link you posted, the slower rider has a greater absolute time savings (1:47 vs. 1:26 over 20K) for a fixed distance, according to those numbers the faster rider actually saves a slightly higher percentage of the original time (4.8% vs. 4.5%, faster vs. slower, by my figgerin' ).

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http://bikeblather.blogspot.com/

I would say, "Actually...that's not quite correct. On an absolute basis, aero equipment is more important to the slower riders than the fast ones. On a percentage basis, it's fairly equivalent...with a slight advantage percentage-wise going to the faster riders."

No smart-ass-ery required ;-)

edit: Oh...and you really aren't getting into any compressibility effects at ~29mph.

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http://bikeblather.blogspot.com/

Aaaaactually:

On a percentage basis he is not.

1:26 savings = 1.4333/30 = 4.78% quicker
1:47 savings = 1.7833/40 = 4.45% quicker

>If you double your speed, you triple the wind resistance

Aero drag is proportional to the square of speed.

You'd have to be going just a little bit faster for compressibility to be an issue...say...another 200mph, maybe 250mph just to be safe.

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I tweet!

What the fuck is 29+mph air compressibility?

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they broke my brain, I am going to ride my bike now.
wondering if I should take my road bike and regular helmet, because fast people dont need that aero stuff.

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Swim with swimmers, bike with cyclists, run with runners. Train with those who are hard to keep up with. Soon you will be hard to keep up with.

The drag force is proportional to velocity squared if you assume all other variables are the same. Cd(slow) would have to be quite a bit lower than Cd(fast) to make up for the exponent on v.

Well I definitely wouldn't steer him here for advice.......you sound like a pompous, egotistical dicktard! If I was at a race and you came up to me and started regurgitating that incoherent drivel, I would either challenge you to a 10k, or ask you if you are seeking counseling for being beaten as a child!

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"I would definitely smell her seat after a century ride"

I would let him continue his thoughts and research it further for my own sanity. The ONE thing that I DO know without a doubt....is that I dont always know without a doubt:)

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A really badly constructed, poorly thought out sentence; that's what that is.

Talking to a prominent bike fitter here in the NY Metro area some time ago, he shared his dismay over the "Super Aero Everythingness" craze that has swept through, as opposed to intelligently applied training (i.e., power based training under the guidance of a knowledgeable coach) as a way to get faster. He mentioned that that reason that Pro Cyclists obsess over aerodynamics is because the combinations of factors (drag, wind resistance, etc) really become serious when you're moving at speeds of 29mph & up. But of course, I mangled his words, & now I can't find his article I remember reading to be able to get it straight.

I'll keep looking for it.

Brian

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Why would a bike fitter know anything about this? IMO pro cyclists don't obsess about aero enough... because they usually don't understand it either.

Maybe this will help you understand. Aero drag is by far the greatest force you have to overcome whether you are going 20mph or 30mph. So if you reduce drag by 10% it has a similarly large effect regardless.

>He mentioned that that reason that Pro Cyclists obsess over aerodynamics is because the combinations of factors (drag, wind resistance, etc) really become serious when you're moving at speeds of 29mph & >up.

He's right in a sense. Aero drag as a proportion of total drag starts taking off about 20MPH and by 29MPH is totally dominant.

But he's wrong if he think you need to be a pro to obsess over aerodynamics. Even at 20-29MPH aerodynamics have a very significant effect. And, as has been noted several times, since the slower people are out on the course much longer (over a fixed distance) the total gains from reduction in aero drag are integrated over a longer time.

The pros, as a whole, should really obsess *more* than they do.

Aero matters to everyone, all the time. Whether you only care about beating your PR, or winning your AG, aero matters.

I spent years on group rides getting spit out the back on every hill and eventually riding home alone.

Against those same guys in races, I would finish right up there in the FOP. My 190 watts at Oceanside produced the same bike split as a friend who rode about 240 watts (actually, I was 4 seconds faster. So there.).

I once matched bike splits in a duathlon by riding 230 watts to another guy's 310.

Aero matters. A lot.

All this nonsense about bike position and producing more power is hooey for a triathlete. We ride triathlons at sub-maximal power anyway. Our power output is a conscious choice to keep it limited, not something limited by bike position.

Not sure if someone mentioned this on a previous post in this thread, but, I'd think the slower folks would benefit from aeromajiq EVEN MORE on a windy day, say a weaker cyclist doing their 1/2 Ironman pace into a 15 mph headwind would be pushing it a lot harder

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Thanks for the graphic, that was one of the things I was looking for.


He does *not* think that. He was simply expressing dismay over how "Aero Everythingness" (my term, not his) was getting trumped up in the periodicals more than the importance of solid training. 'Aero won't help you all that much going up on the big hills' was more his point.

Thanks again,

Brian

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Welcome to the Church of Briantriology!

Thing about hills though, you normally get to come back down. Providing the road allows it, aero could help you outdistance them, without even pedalling.