At least those tested in the latest by velonews in the North Carolina A2 wind-tunnel. What is interesting is that the S5 is only 20.5 watts faster than their control non-aero frame. The Venge says that it saves 25 watts in their marketing piece, which is not substantiated by the Velonews tests. A good read in their mag.
Correction, cervelo was 20.5 watts better than standard road bike.
Is there an online link?
only 19 watts?
lol
ONLY NINETEEN WATTS?
seriously, 19 watts is the kind of claim that people dismiss as marketing bs because it sounds so ridiculous
only 19 watts?
lol
ONLY NINETEEN WATTS?
seriously, 19 watts is the kind of claim that people dismiss as marketing bs because it sounds so ridiculous
compared to a totally unaero road frame with fully exposed cables? You get more than 19 watts from good tires and latex, you get more than 19 watts from an aero helmet. The worst in the test was less than 10 watts better than the control bike. Don’t get me wrong- 19 watts is good- but it’s a pricey 19 watts- and that is the BEST aero road frame.
19 watts is about 2x what you would tend to get from an aero helmet.
aero helmet ~30 seconds per 40k aka ~10 watts
tires, maybe, going from the very worst to the very best.
compared to a totally unaero road frame with fully exposed cables? You get more than 19 watts from good tires and latex, you get more than 19 watts from an aero helmet. The worst in the test was less than 10 watts better than the control bike. Don’t get me wrong- 19 watts is good- but it’s a pricey 19 watts- and that is the BEST aero road frame.
So why not do all the thins you mentioned plus a S5? They aren’t mutually exclusive are they?
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…
So say we take a rider with a good fit on a non-aero road bike, then put the same rider on an S5 with Aero helmet, deep wheels, and the other Aero tricks. How much faster over 40k?
Not to mention the S5 VWD actually weighs the claimed 990 grams, as opposed to the McLaren Venge coming in around 1100-1150 grams.
So say we take a rider with a good fit on a non-aero road bike, then put the same rider on an S5 with Aero helmet, deep wheels, and the other Aero tricks. How much faster over 40k?
well the frame alone would be on the order of a bit over 1 minute per 40k, if we assume the 19 watts reflects reality.
all of the issues Rapp points out could mean the ‘real’ answer is a bit more, or a bit less.
and any hills would discount the gains a bit.
I couldn’t find any info on the new issue on the web. Which bikes did they test?
Are you saying aero improvements are one for one additive? Real world results with a rider don’t seem to show that. The frame is definitely faster, but is it truly 20.5 watts faster with a rider, probably not. Zipps data with cancellera showed that with him aboard versus wheel test savings, when just testing a wheel.
Are you saying aero improvements are one for one additive? Real world results with a rider don’t seem to show that. The frame is definitely faster, but is it truly 20.5 watts faster with a rider, probably not. Zipps data with cancellera showed that with him aboard versus wheel test savings, when just testing a wheel.
For the improvements he’s talking about (i.e. helmet, tires, etc.), yeah…pretty much “one for one additive”.
BTW, the ~20W savings matches the difference between measured in the Lava mag test of the Madone vs. S5, which I “eyeball” as ranging from ~17-22W difference across yaws, so I’m not surprised by that number.
Where are you seeing this VN test? I looked online and can’t find it referenced anywhere? I get the digital edition, but didn’t log in last night and check for a new issue…
I had always thought that skin suit, helmet, wheels were worth considerably more than a frame. Is this not the case anymore? Interesting developments if true.
Do tests show a frame is 1 for 1 additive in comparing tunnel watt savings versus open road with rider aboard data? Wheel only data does not show this consistency.
Do tests show a frame is 1 for 1 additive in comparing tunnel watt savings versus open road with rider aboard data? Wheels do not show this consistency.
you are saying the word additive but I think you are asking if 20 watts saved with a bare frame == 20 watts saved with a frame+rider
and the answer is no, might be more, might be less.
the tour magazine tested with a dummy rider on board if you want some data points in that case. so did some of the cervelo data in the p4 slowtwitch article, and their s5 white paper.
Any real world data with rider aboard pedaling?
Any real world data with rider aboard pedaling?
Don’t wind tunnels exist in the “real world”? :-/
Any real world data with rider aboard pedaling?
plenty of people have used the chung method to collect such data in the field. I believe Tom has data comparing bikes like the P2k to the P3 where differences ‘in the real world’ were consistent with Cervelo’s claims
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
as for pedaling, damon has interesting remarks on that here:
http://forum.slowtwitch.com/gforum.cgi?post=3235262;search_string=pedaling;#3235262
Any real world data with rider aboard pedaling?
Don’t wind tunnels exist in the “real world”? :-/
No. The two are mutually exclusive.
The best you can do for bike+rider+pedalling is an “Aerolab” test . Take a powermeter, the most perfectly flat stretch of road wind absolutely zero wind, and ride at the same power back and forth all day. Preferably during the heat of the day, so that temperature (and thus air density) remain constant.
Even under the most perfect conditions, there is still a significant margin for error: riding on the “rut” from cars will have different rolling resistance than riding outside of it. Cars passing you will give you an extra .2 mph on the same wattage, etc etc etc.
This is why wind tunnel tests are the best we can do - things like riders pedaling add a LOT of time to these tests. It would be nice to test every frame and wheel combination for every rider position at every yaw angle, but remember that there are 10ish top-of-the-line aero frames, tons of wheel choices and riders race everywhere from in the hoods to the tops to the drops. Assume that you want to test every setup from -15 to +15 deg of yaw at 3 degree increments, and suddenly you’ve got 3,000 setups to test.
Obviously, that’s impractical, so you have to do with a few guidelines, such as faster frame = faster frame + rider.
Unfortunately, there are a few thing contrary to our guidelines: ie, a flat disc may be faster on a P3 than a lenticular disc. As such, the guideline of “faster frame + faster wheels = faster” may not hold true in all cases.
…
That said, the only money I’ve ever won is from finishing on the podium in a bike race, on my totally non-aero frame with non-aero wheels*, so none of this matters to me. I time trial on a 3rd hand P2K.
*: Externally routed square tubes with 24h 30mm training wheels … and fast tires. 