Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews (Page 2): Triathlon Forum: Slowtwitch Forums

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Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews

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Jamaican

Apr 3, 12 10:53

Post #26 of 73 (3912 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [Tom A.] [In reply to]	Quote \| Reply

Tom A. wrote:

Congratulations...I don't know where to start in responding to all of this...

I was just waiting for this LOL.

I'm sorry I offended you when I called you stupid. I honestly thought you knew.

For Sale: TT Helmet, Zipp Vuka, Torhans, SRAM Force, Vision |

MTM

Apr 3, 12 11:30

Post #27 of 73 (3881 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [jackmott] [In reply to]	Quote \| Reply

jackmott wrote:

cervelo has been using an on board wind meter lately (to account for yaw ) for field testing as well, though I don't know if any of that data has been made public

Interesting, hadn't heard that before (though it seems very logical). Do you have any link for more information or where you heard/read it? I would like to hear Cerv�lo's input on usual yaw ranges for different speeds. The P4 excels at low yaw angles, I wonder how intentional this is - did they put a lot of time into getting really good low-yaw numbers or was it just easy (easy as in not super-duper hard) to get those numbers and they then just went along with it?

valdlaw

Apr 3, 12 11:57

Post #28 of 73 (3852 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [Rappstar] [In reply to]	Quote \| Reply

Rappstar wrote:

I'd be careful reading too much into the hard numbers. I.e., to say that the 25w number Specialized presents is not supported is a bit meaningless, because you don't actually measure watts in the wind tunnel. You measure change in CdA at various yaws. Even the same data could be assumed to present different wattage savings if you weighted various yaws differently. And there is substantial variance in tunnels as well. Plus, different bikes do better with different wheels. And how did they normalize geometry. Same bar height? Or same # of spacers? How was cable housing length done? Minimal amount possible?

Complete bike tests CAN BE valuable, but I generally think they are more to sell magazines (and bikes) than to be precise and informative.

DISCLAIMER: I haven't read this article. This is just based off these types of articles...

I have the issue and they used one Wheelset for all bikes, minimal cable housing , no seats or pedals. The S5 comes out about 5 watts ahead of the Venge (comparing their bikes against the S3 which won this test last year) which I think is consistent with Specialized's and Cervelos claims. However I'll go with the Tour test which had the Venge beating the S5 in the tunnel, but I have a Venge ;). Btw the Venge beat the S5 overall in the Velonews test :)

(This post was edited by valdlaw on Apr 3, 12 11:58)

Tom A.

Apr 6, 12 18:45

Post #29 of 73 (3631 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [valdlaw] [In reply to]	Quote \| Reply

valdlaw wrote:

Btw the Venge beat the S5 overall in the Velonews test :)

Ummm...yeah...I just got my digital edition delivered and took a look at the "review". Here's a few comments I had pop into my head while reading it:

- Their "scientific torsion" test is basically useless. Nice try, but they should probably look into something different. First of all, the "boundary condition" of the fork mount doesn't represent reality. Secondly, the rankings based on their measurements don't necessarily correlate with the subjective impressions of "handling", "comfort" and "acceleration". Seeing that, you'd think they'd realize their so-called "stiffness" measurements aren't exactly reflecting what they think they are reflecting. I looked at the actual measurements as well and tried to figure out how they used them for their overall "scientific" number...and, I can't make heads or tails of how they ranked them and assigned the points.

- They specifically state that the Foil doesn't handle as well as the S5 and the Venge, but then give it the same subjective handling ranking...hmmm :-/

- The S5 is a mere 0.08 lbs heavier than the Lightspeed and they ding it a FULL point (on a scale of 5) relatively speaking, that's a 20% lower score! The Lightspeed is nearly a full pound heavier than the Foil, and it only gets dinged one point on the same scale...that's just wacky.

- They mention you have to drill the frame for Di2 on a Foil if you get a mechanical version frame, but then give it the highest score for "user friendliness"...really?

- They criticize the S5 for have an "obscenely tall" head tube, and yet the stack on the 56 S5 is only 14 mm taller than the 56 Venge stack, and only 11mm taller than the 56 Foil. Mr. Fretz claims that he couldn't get his preferred position on the 56 even with a -17d stem. I have a feeling he didn't try to find a low profile headset cone. He also claims he could have sized down to a 54 and then used a -17d, 150mm stem...but, since the 54's reach is only 9mm shorter than the 56, does that mean he currently runs a 140mm stem now? I highly doubt that...Something's not adding up with this complaint

Anyway...long story short, this "review" seems to be a lame attempt at putting numbers up to justify a pure opinion. Heck, in the last aero bike test they even admitted that they were looking for reasons not to like the Cervelo just because they thought it was over-hyped. Oh well, I guess they figured out how to accomplish that.

It's a good thing the wind tunnel numbers tell the truth ;-)

http://bikeblather.blogspot.com/

jcd

Apr 6, 12 19:22

Post #30 of 73 (3588 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [Tom A.] [In reply to]	Quote \| Reply

They also state that their stiffest bike from "Aero Road Bikes 1.0," the Ridley, would only have ranked fourth in the stiffness test in 2.0, but as I recall they complained at the time about how it was almost too stiff. Then, yes, there's the subject of what the hell their stiffness test actually "means." With aero testing, they say they're doing it because a lower drag frame makes you faster. Fair enough. With the stiffness testing, there's this unsaid subtext that stiffer is better somehow, and seemingly on a completely arbitrary scale... And of course they can't hold back from macho statements about how wanting decent ride quality is for whining, easily-broken riders. Yep, that's what I think when I hear that Cancellara wants to ride the softer-riding Domane all year. I know everyone keeps coming back to this, but until I see a well-controlled study demonstrating real correlations between increases in stiffness and increases in performance, I'm very confused as to why people keep harping on about its importance. Cavendish seemed to do ok on the Venge. I would honestly prefer to hear just the subjective riding opinions, rather than dressing them up in this poor attempt to validate them with meaningless numbers.

p.s. I did my own rejigging of the VN conclusions, by eliminating the score for stiffness and for weight. Result: S5 first, Foil second, Venge third (just behind the Scott, and made up for by ignoring silly subjective riding scores), Litespeed fourth (edited to add p.s.).

(This post was edited by jcd on Apr 6, 12 19:26)

Tom A.

Apr 6, 12 21:39

Post #31 of 73 (3502 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [jcd] [In reply to]	Quote \| Reply

Oh yeah...one more nitpicky thing: Zinn keeps repeating this statement (he made the same one in the previous review) - "50 grams of drag force = 5W power savings = .5s/km at 30 mph". That's not exactly correct and is IMO misleading.

The correct statement would be "50 grams of drag force when tested at 30mph is approximately equivalent to 5W power savings = .5s/km at typical race speeds".

Like I said, nitpicky, but there's a difference.

http://bikeblather.blogspot.com/

damon_rinard

Apr 7, 12 3:02

Post #32 of 73 (3399 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [Tom A.] [In reply to]	Quote \| Reply

Good points both of you, I'd noticed some of the same things you pointed out.

In fact, regarding stiffness testing, we at Cervelo noticed years ago that many lab tests don't match reality. So we developed one that does. We've written about how we developed the Cervelo torsion test in the "New Tests & New Engineering Tools" tech presentation here: http://cervelo.com/.../tech-presentations/. This test includes a critical component most stiffness tests leave out - the rider!

However, I'd like to give the VN boys credit for trying. It wasn't that long ago we were all crying out for more objective testing, and while there's still plenty of subjectivity in bike test reporting (honestly, not *everything* can be quantified), I think, like TOUR Magazin, the VN crew are starting down a road that could lead to less apparently "personal opinion" pieces. At least they're going to wind tunnels these days!

Cheers,

Damon

P.S. I credit VN and TOUR for paying for making the trip to the wind tunnel and, at the same time, I also completely understand their not "giving" away the articles on the web. Wind tunnel testing can be expensive. How many of us were asking for non-manufacturer-run wind tunnel tests? And here they are. -DGR
===========
Damon Rinard, Senior Advanced R&D Engineer
Vroomen.White.Design
http://www.cervelo.com
http://www.bbright.net

redtdi

Apr 7, 12 4:07

Post #33 of 73 (3357 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [damon_rinard] [In reply to]	Quote \| Reply

VN and Tour magazine need to keep up this testing (and get better at it over time). I bought Tour Quarterly and VN digital PURELY because of the aero testing they're doing.

The wind tunnel expensive but they both have more subscriptions as a direct result.

Ken

"the trick is to keep losing weight until your friends and family ask you if you've been sick. then you know you're within 10 pounds. if they start whispering to each other, wondering if you've got cancer or aids, you're within 5. when they actually do an intervention, you're at race weight." - Slowman

Tom A.

Apr 7, 12 7:26

Post #34 of 73 (3275 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [damon_rinard] [In reply to]	Quote \| Reply

damon_rinard wrote:

Exactly! It certainly does make sense to actually measure the loading (like was done with the strain gage bike) and then design a test to replicate that loading as a starting point, rather than just come up with some sort of load test based on assumption...but, maybe that's just the engineer in me talking ;-) Have you guys ever considered making your "inertial torsional load case" test public? Or, would that be potentially giving up too much IP?

damon_rinard wrote:

However, I'd like to give the VN boys credit for trying. It wasn't that long ago we were all crying out for more objective testing, and while there's still plenty of subjectivity in bike test reporting (honestly, not *everything* can be quantified), I think, like TOUR Magazin, the VN crew are starting down a road that could lead to less apparently "personal opinion" pieces. At least they're going to wind tunnels these days!

I agree...but, if one is going to go through the bother of trying to quantify these things, then I would rather they did a better job of defining the tests. They're getting pretty good at the wind tunnel side of things, but they have some good "resources" at the tunnel helping them in that regard.

I would rather they did no test at all and just relied on subjective comments if it ends up that the tests don't correlate to the subjective observations very well...that just means that they're not actually "testing" what they think they are testing.

It's sort of like in their wheel tests where they spend a lot of time measuring the rotational inertia of the different wheels (and give them fairly significant weightings in their evaluations) but then their impressions of "acceleration" don't match those measurements (e.g. having one of the highest rotational inertia wheels rated the best in subjective "acceleration"). That should give them pause about their test protocol and rating weightings, along with an analysis of what the actual "drivers" of acceleration are...and yet it doesn't seem to do so. It almost seems as if it's a case of "We spent a lot of time and energy making a wheel inertia testing device, and by God, we're going to use it!" :-/

http://bikeblather.blogspot.com/

RChung

Apr 7, 12 7:49

Post #35 of 73 (3249 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [Tom A.] [In reply to]	Quote \| Reply

Tom A. wrote:

Things would be a lot simpler if people would just standardize on reporting out the CdA, eh?

Tom A. wrote:

It almost seems as if it's a case of "We spent a lot of time and energy making a wheel inertia testing device, and by God, we're going to use it!"

One-trick ponies of the world, unite!

(This post was edited by RChung on Apr 7, 12 7:50)

Tom A.

Apr 7, 12 7:53

Post #36 of 73 (3242 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [RChung] [In reply to]	Quote \| Reply

RChung wrote:

Things would be a lot simpler if people would just standardize on reporting out the CdA, eh?

Ding! ding! ding!....winner, winner, chicken dinner! :-)

Exactly...then one wouldn't need that qualifier of "tested at 30 mph" and you could have nearly the same ROT, i.e. "at typical race speeds, .005 m^2 of CdA = 5W = 0.5s/km"

http://bikeblather.blogspot.com/

Tom A.

Apr 7, 12 7:55

Post #37 of 73 (3239 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [RChung] [In reply to]	Quote \| Reply

RChung wrote:

One-trick ponies of the world, unite!

Well...except not all pony tricks are as useful as others ;-)

http://bikeblather.blogspot.com/

Power13

Apr 7, 12 8:12

Post #38 of 73 (3220 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [Tom A.] [In reply to]	Quote \| Reply

Quote:

the stack on the 56 S5 is only 14 mm taller than the 56 Venge stack, and only 11mm taller than the 56 Foil.

"only" 14mm? That is ~5/8". In an area where the smallest differences can make a significant difference in position and feel, that is not "only" - that is a substantial difference.
__________________________________________________
�I want to tell the world of cycling to please join me in telling Pat McQuaid to f##k off and resign." - Greg Lemond

jcd

Apr 7, 12 8:13

Post #39 of 73 (3220 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [damon_rinard] [In reply to]	Quote \| Reply

I too am very glad that VN are doing this testing. I'm pretty embarrassed by how quickly I dashed out to get my copy this month.

I think what I'd like to see is a page of these tests dedicated to a "right to reply" from the manufacturers concerned, to give us some better context for how the engineers and designers view the various results, rather like you're doing here Damon. I'm fairly sure, for instance, that Cervelo could have made the S5 "stiff" enough in the areas tested by VN to come closer to the Foil, and I also suspect that Scott could have made the Foil a bit more compliant. The fact that neither company did is interesting to me, and speaks to the various interpretations of how to deal with the various forces acting on the bike/rider combination in various forms of riding. I was very interested in the concept of the Foil because I hoped it would give Scott the ability to tune for lateral stiffness and vertical compliance, and the fact that they appear not to have done this is disappointing to *me,* but I suspect not to everyone. I want aerodynamic performance, good handling and compliance. If improvements in "stiffness" in certain areas can help achieve these things then I agree with VN that stiffness is important, but it has to be stiffness in areas and in directions that matter, and VN need to be able to articulate why and how the areas they have chosen to test matter.

The S5 is significantly stiffer than the S3 in the VN test, but a number of Garmin riders have been on the S3 for years, including power houses like Hushovd and kit-obsessives like Millar. I'd be interested to hear if they were complaining about the "lack" of stiffness in the S3 (I know it was hard to convert some of them away from the R series, but not Millar), or whether they didn't notice or care about the difference, and if these ride opinions corresponded with actual data gathered by Cervelo. Er... that's quite a lot of proprietary information, but what the hell.

Tom A.

Apr 7, 12 8:28

Post #40 of 73 (3202 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [Power13] [In reply to]	Quote \| Reply

Power13 wrote:

Quote:

the stack on the 56 S5 is only 14 mm taller than the 56 Venge stack, and only 11mm taller than the 56 Foil.

"only" 14mm? That is ~5/8". In an area where the smallest differences can make a significant difference in position and feel, that is not "only" - that is a substantial difference.

Well...to put it in perspective, on a 120mm length stem, going from a -6d stem to a -17d stem nets an additional 22mm of "drop"...let's just say that if he wasn't using a -17d stem on the Foil or Venge, then he should have been able to get the same position with a -17d stem on an S5.

And that's not even considering if he tried using a lower profile headset "cone". The pic in the article shows a fairly tall one...

Like I said, something's not adding up about this complaint.

http://bikeblather.blogspot.com/

valdlaw

Apr 7, 12 8:48

Post #41 of 73 (3203 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [Tom A.] [In reply to]	Quote \| Reply

Tom A. wrote:

valdlaw wrote:

Btw the Venge beat the S5 overall in the Velonews test :)

I thought it was kind of amusing that they called their winning bike, the Foil, a "Boneshaker" - not exactly a convincing selling point.
BTW Tom I tend to agree with the tunnel data in this test based on Specialized's own information, but how do you account for the disparity with the Tour test? Cables?

justkeepedaling

Apr 7, 12 9:05

Post #42 of 73 (3182 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [valdlaw] [In reply to]	Quote \| Reply

There were a few issues with the Tour test, heck, look at the size of the error bars... They were larger than the actual gap between many bikes.

What I'm interested in, which level S5 and Venge did they use? It makes a small difference for the weight and value category, I guess.

(This post was edited by justkeepedaling on Apr 7, 12 9:06)

Power13

Apr 7, 12 10:41

Post #43 of 73 (3129 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [Tom A.] [In reply to]	Quote \| Reply

Tom A. wrote:

Power13 wrote:

Quote:

the stack on the 56 S5 is only 14 mm taller than the 56 Venge stack, and only 11mm taller than the 56 Foil.

"only" 14mm? That is ~5/8". In an area where the smallest differences can make a significant difference in position and feel, that is not "only" - that is a substantial difference.

Whether his position issue is valid or not was not really my point - dismissing a 14mm difference as a minor difference was the point I was making. A 14mm HT difference is a substantial difference in frame geometry.
__________________________________________________
�I want to tell the world of cycling to please join me in telling Pat McQuaid to f##k off and resign." - Greg Lemond

jackmott

Apr 7, 12 14:28

Post #44 of 73 (3035 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [Power13] [In reply to]	Quote \| Reply

Yeah, and taller makes the bike stiffer, and requires only finding a way to bring your bars down 14mm to make the position the same. which for *almost* everybody is easily accomplished.

Power13 wrote:

"only" 14mm? That is ~5/8". In an area where the smallest differences can make a significant difference in position and feel, that is not "only" - that is a substantial difference.

Memorial day sale at ATC and Meet Pro Triathlete Matty Reed - Sat May 25 - Captex!
The newest tri shop in Austin - ATC 360
Freelance sports & outdoors writer Kathryn Hunter

jackmott

Apr 7, 12 14:31

Post #45 of 73 (3030 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [Power13] [In reply to]	Quote \| Reply

Power13 wrote:

in what sense is it substantial?
it makes the bike no different or better for 99.9% of people and impossible to fit on for the remaining 0.1%

dissscuss!
=)

Memorial day sale at ATC and Meet Pro Triathlete Matty Reed - Sat May 25 - Captex!
The newest tri shop in Austin - ATC 360
Freelance sports & outdoors writer Kathryn Hunter

Tom A.

Apr 7, 12 14:47

Post #46 of 73 (3006 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [Power13] [In reply to]	Quote \| Reply

Power13 wrote:

Well, actually...14mm is pretty minor. One can easily accommodate that sort of a difference with various equipment choices (as I detailed above).

The point I was making is that if that 14mm was truly a "deal breaker" for him, then something is really amiss with the reviewer's claim that his only other option was the next size down frame and a 150mm stem. I'm not buying it.

You know, I'm not necessarily known as having a "sit up and beg" road position, and I had no difficulty replicating my position on the S5 even without resorting to a -17d stem...then again, I'm also not using the stock 25-30mm tall headset "cone" either...

http://bikeblather.blogspot.com/

Power13

Apr 7, 12 19:08

Post #47 of 73 (2879 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [Tom A.] [In reply to]	Quote \| Reply

Tom A. wrote:

Power13 wrote:

Well, actually...14mm is pretty minor..

OK...we'll have to agree to disagree.

I never said it couldn't be accommodated through different stems, etc. But a 14mm difference in a HT is substantial.
__________________________________________________
�I want to tell the world of cycling to please join me in telling Pat McQuaid to f##k off and resign." - Greg Lemond

bobby11

Apr 9, 12 12:49

Post #48 of 73 (2658 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [mlinenb] [In reply to]	Quote \| Reply

I've got a few minutes to spare so I want to share this funny (to me, anyway) story. This past Saturday morning in the wee hours (around 5 am) I stumbled onto this thread while eating my Cheerios before heading out for the 90 minute drive to Monroe, GA for a century ride I'd never done before. I have a Venge I got a few weeks back. It's a great bike, but it IS stiff ... and harsh at times on the chip and seal roads around my home. I almost decided not to take it for the century, but changed my mind after I found an old set of Michelin PR3s I felt I could run at 100 psi comfortably. So the car was packed with my fancy new aero bike and I was fixin' to be off to my first century of 2012 and I stumble onto this thread saying my Venge is inferior to the S5. Crap! I was bummed. I happen to know mlinenb. We've met at a few time trials over the years. This morning I was kinda pissed at him for spoiling my Cheerios before a big century.

Cut to about 10:30 am and about half way through the century. I've been in a fast lead pack of roadies and we've got nearly a 25 mph average going. But there's been this one tri guy who's been patroling the pack ... sometimes taking the lead and driving the pace, sometimes just rolling up and down on the yellow line as if trying to see who he's hurt and who he hasn't. So here at around the 50 mile mark he settles in next to me. At first, I admire his awesome aerobars (Felt Devox bars which I've ordered since I got home from that ride). Then recognition hits. "Mark? Are you Mark?" He looks over, and "BOB!!!!!" It's mlinenb! So I tell him how he spoiled my Cheerios and how he's given me a complex about my brand new bike.

But the long and short of it is that, despite my 56 years, I was in the final six who rolled in at the pointy end out of 650 starters after 99.4 miles. It was the fastest century I've ever done and it was on my "inferior" new Venge. (Owe a lot to mlinenb who took many really nice pulls on a nicely aero P3/Devox setup.)

I've been riding for a lot of years and I ride between 12,000 and 15,000 miles per year. I've owned a lot or road and TT bikes. Perhaps the S5 is a thimble full of watts better in a straight line. I can't imagine it could handle better than the Venge. This bike is astounding me. When I want to go, it goes. Telepathic! I'm a sucker for marketing and media studies like the VeloNews article. But if you offered me a straight-up trade, my Venge for an identically equipped S5, I'd laugh you off. No way, Jose!

jackmott

Apr 9, 12 12:51

Post #49 of 73 (2650 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [bobby11] [In reply to]	Quote \| Reply

Bob your story is obviously untrue. An aero road bike like that would have pounded your old bones to submission after 100 miles. I read that here on ST ;)

Now how the hell did I do 11 hours on an aero road frame this weekend and feel fine? IT MUST BE MAGIC?

Memorial day sale at ATC and Meet Pro Triathlete Matty Reed - Sat May 25 - Captex!
The newest tri shop in Austin - ATC 360
Freelance sports & outdoors writer Kathryn Hunter

(This post was edited by jackmott on Apr 9, 12 12:57)

bobby11

Apr 9, 12 13:37

Post #50 of 73 (2559 views)

Re: Cervelo S5- King of the Aero Bikes (in the windtunnel)- Velonews [jackmott] [In reply to]	Quote \| Reply

It's the shorts, man ... it's the shorts!

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