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Re: Does anyone really think a frame saves 9 watts? [damon_rinard] [ In reply to ]
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damon_rinard wrote:
Thanks Mark, I see it now:

"(and when you factor in sitting in a pack, where wind resistance is reduced 30-40%, that 4-5 watts becomes 1-2 watts)."

Hate to pick nits but those aren't Gerard's words or numbers, and the math isn't even right. Yeah, a Watt or two here and there isn't super important in the big scheme of things, so it's easy to see why Gerard would overlook it, but I can see where this small error lead to your misunderstanding it's now "10 times" what it was. It's not that big a difference.

Does that clear things up?

Clear as mud, as he qouted it and replied back to it. Can you guys put that tipping point presentation on the wehsite again and post a link? Thanks.
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Re: Does anyone really think a frame saves 9 watts? [damon_rinard] [ In reply to ]
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damon_rinard wrote:
Interesting. What might the Cervelo range look like if we followed your thoughts?
Damon:

Ignore him.

Tom:

Shut up.
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Re: Does anyone really think a frame saves 9 watts? [rickn] [ In reply to ]
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rickn wrote:
As in perhaps the bike rides like piece of wood. Aero is only the end all be all if bicycle racing was a math equation, which it is not.

Far from that. I have ridden it and it rides like the S3, but a little more comfortable. The S5 is stellar bike. I guess I have to wonder, "why wouldn't you want a faster bike, if it was available?"
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Re: Does anyone really think a frame saves 9 watts? [road2tri] [ In reply to ]
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Dig through the threads its been discussed. Of course everyone who races would want a faster bike, but people have different perceptions and aero is just one of them. Comfort, fit, handling stiffness, etc is in some ways in the eye of the beholder.

I'm not even sure how to define comfortable when it comes to bikes, but just like seats, shoes, shorts helmets etc I'm pretty comfortable with assuming that some frames just feel better to one person vs another. That combo of handling, fit, stiffness etc that gives you more a bit more confindence in a tight corner of sprint to go all out.

Look at cars. In the 50s-70s comfort mean trying to make riding in a car like sitting in an easy chair in your living room. It turns out that a lot of people like to have a bit of feedback a bit of noise, a feeling that they are driving. Some prefer the dead silent living room feel. Thats OK, its a hobby, nothing wrong with someone actually enjoying how there bike rides no matter how they define it.

Styrrell

Styrrell
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Re: Does anyone really think a frame saves 9 watts? [RChung] [ In reply to ]
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RChung wrote:
damon_rinard wrote:
Interesting. What might the Cervelo range look like if we followed your thoughts?

Damon:

Ignore him.

Tom:

Shut up.

Yeah...I know...I wasn't sure about actually mentioning it, since I actually like the idea of being able to get a world class performing frame at a baseline price ;-)

All I'm sayin' is that manufacturers shouldn't wonder why people value weight or stiffness over aero when that's how the pricing structure of bikes typically works out...

http://bikeblather.blogspot.com/
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Re: Does anyone really think a frame saves 9 watts? [damon_rinard] [ In reply to ]
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Damon, wouldn't riders that prefer the R5 (or R3) over the RS, and who need to use -17° stems (as in below) would prefer an S5 with a shorter headtube?









Thanks beforehand for your expert comments,

Sergio

-------------------------------------------------------------------
Note: English is not my first language. Please read this translated post considering that.


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Re: Does anyone really think a frame saves 9 watts? [mlinenb] [ In reply to ]
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Apparently you did not notice me pointing this out all week :) the only one who will respond is Tom a and his opinion was the first numbers were wrong. So if those numbers were wrong and there has been no explanation why, you better not question these numbers!

Ride Scoozy Electric Bicycles
http://www.RideScoozy.com
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Re: Does anyone really think a frame saves 9 watts? [Sergio Escutia] [ In reply to ]
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Hi Sergio,
Yes, some riders prefer a shorter head tube.
Also, as you know, some riders prefer a longer head tube.
We've chosen the stack and reach that fits the most riders the best.
Anyone can choose the equipment needed to get as close as they like to their preferred position.

Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)
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Re: Does anyone really think a frame saves 9 watts? [styrrell] [ In reply to ]
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styrrell wrote:
Dig through the threads its been discussed. Of course everyone who races would want a faster bike, but people have different perceptions and aero is just one of them. Comfort, fit, handling stiffness, etc is in some ways in the eye of the beholder.

I'm not even sure how to define comfortable when it comes to bikes, but just like seats, shoes, shorts helmets etc I'm pretty comfortable with assuming that some frames just feel better to one person vs another. That combo of handling, fit, stiffness etc that gives you more a bit more confindence in a tight corner of sprint to go all out.

Look at cars. In the 50s-70s comfort mean trying to make riding in a car like sitting in an easy chair in your living room. It turns out that a lot of people like to have a bit of feedback a bit of noise, a feeling that they are driving. Some prefer the dead silent living room feel. Thats OK, its a hobby, nothing wrong with someone actually enjoying how there bike rides no matter how they define it.

Styrrell

I think this was in response to my post. If not, ignore.

Everyone is assuming that because this is an aero frame that it rides like a TT rig. I can tell you firsthand that it doesn't, and I can compare it against more bikes than most (Pinarello Dogma, Pinarello Prince, Cervelo S3 and S2, Ridley Noah, Blue AC1, Scott Addict R1, Look 595, Look 695, Orbea Ordu, many aluminum frames, and many, many steel frames).
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Re: Does anyone really think a frame saves 9 watts? [msuguy512] [ In reply to ]
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drag force vs power and a guy who can't let it go that gerard said "10 points" when he shouldn't have.



msuguy512 wrote:
Apparently you did not notice me pointing this out all week :) the only one who will respond is Tom a and his opinion was the first numbers were wrong. So if those numbers were wrong and there has been no explanation why, you better not question these numbers!



Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter
Last edited by: jackmott: Jul 4, 11 5:01
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Re: Does anyone really think a frame saves 9 watts? [jackmott] [ In reply to ]
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jackmott wrote:
drag force vs power and a guy who can't let it go that gerard said "10 points" when he shouldn't have.
Maybe he meant 10 points out of 100.
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Re: Does anyone really think a frame saves 9 watts? [RChung] [ In reply to ]
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I think the S5 has just validated itself...
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Re: Does anyone really think a frame saves 9 watts? [justkeepedaling] [ In reply to ]
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Re: Does anyone really think a frame saves 9 watts? [jackmott] [ In reply to ]
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That's what I meant, Thor was unbelievable
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Re: Does anyone really think a frame saves 9 watts? [damon_rinard] [ In reply to ]
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damon_rinard wrote:
1. The 1.5% difference you quote is drag force (or CdA, they're linearly related), not time, not power, not speed. Percent difference in power isn't the same as percent difference in drag force; power and drag force are not linearly related (see the "Total" curve on Figure 4's chart in the white paper; it's not a straight line). So differences in power have different percent results than differences in drag force; the 5.2% (your calculation result) is a difference in power, not CdA.

Hi Damon-

After some more thought- the 1.5% doesn't tell anyone all that much- as (I think most riders) want to boil numbers down to watts saved or at least grams of drag saved. What was the total force in grams of drag for the 2009 tests for the S2 and for the R3?

Thank you-
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Re: Does anyone really think a frame saves 9 watts? [mlinenb] [ In reply to ]
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Hi Mark,

I agree with you. We discuss grams of drag internally because that's what the wind tunnel measures, but grams sometimes don't mean much to typical riders; what if you're taller or smaller, faster or slower?

Like you, I'm leaning towards Watts as the common currency. But that requires a lot of assumptions - tunnel test speed, rider size and riding speed, etc.

Then there's time saved - but also requires assumptions about race conditions like distance and duration, and how much climbing and drafting there is.

Its not easy to describe aero effects simply.

All of which I guess is an argument in favor of CdA... Dang, would that make Tom and Robert right again?

Nevertheless I think I can look up the data that should answer your question.

Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)
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Re: Does anyone really think a frame saves 9 watts? [justkeepedaling] [ In reply to ]
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Actually, it is never the bike, do not kid yourself.

justkeepedaling wrote:
That's what I meant, Thor was unbelievable
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Re: Does anyone really think a frame saves 9 watts? [road2tri] [ In reply to ]
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It was in response to you, but it wasn't inresponse to the S5 in particluar just the more generic question of why a rider would choose any less aero frame vs a more aero one. I think how it fits, feels, and handles is a perfectly valid reason.


I'd love to know how much lead time some of the riders are given prior to getting some of the frames before they debut for the public at the Tour. I can see any sprinter using a new frame after a 20 minute ride in aparking lot, but I wonder if a couple of days will do it or a couple of weeks. I'm sure it varies by riders and of course below the star level you likely have to use what your told to.

Styrrell

Styrrell
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Re: Does anyone really think a frame saves 9 watts? [damon_rinard] [ In reply to ]
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damon_rinard wrote:
Hi Mark,

I agree with you. We discuss grams of drag internally because that's what the wind tunnel measures, but grams sometimes don't mean much to typical riders; what if you're taller or smaller, faster or slower?

Like you, I'm leaning towards Watts as the common currency. But that requires a lot of assumptions - tunnel test speed, rider size and riding speed, etc.

Then there's time saved - but also requires assumptions about race conditions like distance and duration, and how much climbing and drafting there is.

Its not easy to describe aero effects simply.

All of which I guess is an argument in favor of CdA... Dang, would that make Tom and Robert right again?

Nevertheless I think I can look up the data that should answer your question.


Thank you for looking it up and sharing what you find. I assume it would be very useful to the end user. Of course there can there can be many differences- but I should assume that you made the above differences identical on both frames- hence a valid comparison is yielded.
Last edited by: mlinenb: Jul 4, 11 10:14
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Re: Does anyone really think a frame saves 9 watts? [damon_rinard] [ In reply to ]
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damon_rinard wrote:
Hi Sergio,
Yes, some riders prefer a shorter head tube.
Also, as you know, some riders prefer a longer head tube.
We've chosen the stack and reach that fits the most riders the best.
Anyone can choose the equipment needed to get as close as they like to their preferred position.

Thanks.

I reiterate that the geometry of the S5 is the best choice for >95% of their potential customers. A longer headtube was a smart business decision, but I will keep my fingers crossed hoping that Cervélo produces an S5 model with a shorter headtube in the future.

And I don't think in these times it would be wise (besides the inherent weakening) to tease the UCI commissaires with this modification (as Cadel did) <smile>.



Best wishes to all the team.

Sergio

-------------------------------------------------------------------
Note: English is not my first language. Please read this translated post considering that.


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Re: Does anyone really think a frame saves 9 watts? [damon_rinard] [ In reply to ]
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damon_rinard wrote:
societies who were more open to innovation

Excellent point! Part of the cultural resistance to change (in my experience) is that those who are currently winning are much less likely to adopt new strategies. Why should they? In some cases it may only be those who are getting pommeled who are willing to take a chance on a new paradigm.
Back the data vs. belief issue. Way back in the mid 90s I was writing an article on time savings for aero equipment and positioning. All the predicted time savings were based on a model and I knew that for some base cases the model was accurate. When I got to the section on aero wheels vs. standard box section 3x type wheels I simply did not believe the model's predicted time savings. So I called my buddy K.C. Willis and we went out to a closed loop course and rode as close as possible to constant power (SRM) with standard wheels and with Specialized Tri Spokes. The data for the two of us matched the model prediction almost exactly. This was not a formal study but it did give my additional confidence in the model.
Cheers,
Jim
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Re: Does anyone really think a frame saves 9 watts? [yme] [ In reply to ]
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Re: Does anyone really think a frame saves 9 watts? [Bio_McGeek] [ In reply to ]
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Bio_McGeek wrote:
damon_rinard wrote:
societies who were more open to innovation


Excellent point! Part of the cultural resistance to change (in my experience) is that those who are currently winning are much less likely to adopt new strategies.
Read Diamond's follow-up: "Collapse: How Societies Choose to Fail or Succeed." He discusses both societies that are "winning" and "failing" that adopt new strategies, and winning and failing societies that don't.
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Re: Does anyone really think a frame saves 9 watts? [jackmott] [ In reply to ]
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Huh?

Ride Scoozy Electric Bicycles
http://www.RideScoozy.com
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Re: Does anyone really think a frame saves 9 watts? [msuguy512] [ In reply to ]
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