That does put it in better perspective. And, it makes it much easier to resist the aero frame bug. So, I (and my wife) thank you!
Now, do one for the aero wheel graphs and save me even more money!!!
Steve
I’ve noticed that theres always “that guy” that complains that a graph is squished too much this way or that, or that a graph doesn’t start at 0.
Graphs are not required to start at zero, and theres no official rule about how to scale an axis.
The two graphs say exactly the same thing to me, one is just awkwardly long.
If you can’t handle the actual numbers being presented in the end, probably not best to look at graphs at all =)
No, what you need to do is stretch out the bottom about 7X to show the differences in drag over the entire bike/rider system, which is ultimately what counts…
the differences are exactly what the drag numbers indicate.
If a P4 saves you 25 grams at a certain yaw over a p3, it remains that whatever the centurion frameset does.
Since nobody intends to ride a Centurion frameset, I don’t see how thats useful.
the chart is intended to help dealers make informed sales pitches to customers about bikes on the market, so bikes on the market are included.
it is not intended to communicate a philosophy and history of aerodynamics, though such a chart would be interesting.
the message I read from longchart
is theres still a long way to go to reach 0!
Naw–kinda of missing the bigger picture, I think. By zooming out on the graph, what one might conclude is that while there are real absolute values that separate the frame samples, it is possible to assume that once one gets into a certain range of well-designed frames that the differences might not be all that huge in the broad scheme of things. What would make this graph complete is the inclusion of data on, say, a circa 1981 Centurion frameset. This would provide useful comparison data.
I think “negate” is the wrong word.
If Bad Position Bob gets on a P4, he is still faster than he is on his Centurion. His bad position is a constant, the frames sweet, sweet tubes are aero either way 
But yes, anyone spending money on a frame to go faster should remember there are lower hanging fruit to be addressed first.
But, if Bad Position Bob has a bad position because of some medical problem, and he is doing his best, he would still be quicker on a trek/specialized/cervelo than a centurion, even with a bunch of spacers.
Not disagreeing with you on one level, but Jens has it right. It’s possible to negate a good amount of the aero advantage of P4 through poor positioning or component selection, while it also could be possible to transform an early steel, round tube frame into a veryfast ride. The key is to remember that frame selection is only one part of a much more complex equation…
I think “negate” is the wrong word.
If Bad Position Bob gets on a P4, he is still faster than he is on his Centurion. His bad position is a constant, the frames sweet, sweet tubes are aero either way
But yes, anyone spending money on a frame to go faster should remember there are lower hanging fruit to be addressed first.
But, if Bad Position Bob has a bad position because of some medical problem, and he is doing his best, he would still be quicker on a trek/specialized/cervelo than a centurion, even with a bunch of spacers.
Not disagreeing with you on one level, but Jens has it right. It’s possible to negate a good amount of the aero advantage of P4 through poor positioning or component selection, while it also could be possible to transform an early steel, round tube frame into a veryfast ride. The key is to remember that frame selection is only one part of a much more complex equation…
We're still in agreement, actually ;) (assuming that the other variables for BP Bob are identical from frame to frame)
Is “BP Bob” the same as “Smiling Bob”?..I think I might know why he can’t get lower on his bike…
This data graph is really helpful on the performance of the bikes, so tell me again, where were the low drag bikes in the TDF this year?
Yeah but, if a Centurion frameset was displayed it would come in above the graph lines, not below, so why are we extending the axis to the floor?
As a guy that looks at spreadsheets and graphs a lot, I had the same takeaway as Jack.
wow. that’s a deep observation. or rather, an observation i’m ashamed that i missed.
nevertheless, the point could still be applied: if you added the centurion and then showed it as being “way out of range”, when in fact the better graph shows the range of Bad Position Bob across a range of positions on a range of frames, its still a bit misleading, no?
well one of em won the tour
one of em won the prolouge
they did pretty well
This data graph is really helpful on the performance of the bikes, so tell me again, where were the low drag bikes in the TDF this year?
.
wow. that’s a deep observation. or rather, an observation i’m ashamed that i missed.
nevertheless, the point could still be applied: if you added the centurion and then showed it as being “way out of range”, when in fact the better graph shows the range of Bad Position Bob across a range of positions on a range of frames, its still a bit misleading, no?
Yeah, it would be interesting to see the drag numbers of the top 5 lowest drag bikes from 1970, 1980, 1990, 2000 and today.
“interesting”, but it wouldnt mean that I didnt want the fastest bike my money could buy.
And the Lotus would still be pretty quick (me want; though mine wont have the funky handlebars)
http://i179.photobucket.com/albums/w289/plasticorange/scan0003.jpg
Yeah, it would be interesting to see the drag numbers of the top 5 lowest drag bikes from 1970, 1980, 1990, 2000 and today.
No, I want more than that. I want to see the top 5 lowest drag bikes plus 2 or 3 others that are clearly suboptimal, measured with a rider in a variety of positions.
Then the $/unit-of-Cda cost will become much more clear. My guess is that you can better results from the right size bike, and that once you’re on the right size bike with the right fitting, the difference of the aero frame is small. Not small enough that those with disposable incomes won’t see it as a reason to spend on the aero frameset, but not large enough for it be compelling.
The only value in doing this would be if you were to look at TT or Tri leg finish times in the same manner. By only looking at the small portion of the graph, you visually remove the very large fixed bias.
What you’re saying is that differences between these frames is fairly low as a percentage of the total. Fine…but, so are finish times. They don’t award placings on percent differences though…they award them on absolute differences.
The plots look like they look because it’s the absolute difference that counts.
Yeah, it would be interesting to see the drag numbers of the top 5 lowest drag bikes from 1970, 1980, 1990, 2000 and today.
No, I want more than that. I want to see the top 5 lowest drag bikes plus 2 or 3 others that are clearly suboptimal, measured with a rider in a variety of positions.
Then the $/unit-of-Cda cost will become much more clear. My guess is that you can better results from the right size bike, and that once you’re on the right size bike with the right fitting, the difference of the aero frame is small. Not small enough that those with disposable incomes won’t see it as a reason to spend on the aero frameset, but not large enough for it be compelling.
and I’d like to know who shot JFK
I disagree that a properly fitted Centurion would be faster than a P4 that’s not perfectly optimized for your body type.
They don’t award placings on percent differences though…they award them on absolute differences.
I don’t believe that human athletics at the pointy end ever involves absolute differences. I was just reading Carl’s comments on his 2nd place masters at world’s TT … lots of remarks about how variable his power output is from day to day. The tiny gaps between the podium spots happen to match the kinds of gaps that could be caused by equipment differences. That doesn’t mean they are actually caused by them. Noting that a given athlete would be faster on bike X than on bike Y, all other things equal, is meaningless - no two passes through the event are the same at this level. Even at sprint distances (100m etc), world class athletes will report a range of experiences across several repeated attempts at the distance. Attempting to pin the 8 second gap that 1st place had over 2nd on his/her bike frame is ignoring a much simpler explanation: 1st place was generating more speed, regardless of the effect of the bike.
They don’t award placings on percent differences though…they award them on absolute differences.
I don’t believe that human athletics at the pointy end ever involves absolute differences. I was just reading Carl’s comments on his 2nd place masters at world’s TT … lots of remarks about how variable his power output is from day to day. The tiny gaps between the podium spots happen to match the kinds of gaps that could be caused by equipment differences. That doesn’t mean they are actually caused by them. Noting that a given athlete would be faster on bike X than on bike Y, all other things equal, is meaningless - no two passes through the event are the same at this level. Even at sprint distances (100m etc), world class athletes will report a range of experiences across several repeated attempts at the distance. Attempting to pin the 8 second gap that 1st place had over 2nd on his/her bike frame is ignoring a much simpler explanation: 1st place was generating more speed, regardless of the effect of the bike.
So you’re saying that a TTX, P3C, P2C Shiv etc, are all so close in drag numbers that it doesnt really matter which bike (among those) you choose?
OR are you saying you’d be faster on the Centurion?
They don’t award placings on percent differences though…they award them on absolute differences.
I don’t believe that human athletics at the pointy end ever involves absolute differences. I was just reading Carl’s comments on his 2nd place masters at world’s TT … lots of remarks about how variable his power output is from day to day. The tiny gaps between the podium spots happen to match the kinds of gaps that could be caused by equipment differences. That doesn’t mean they are actually caused by them. Noting that a given athlete would be faster on bike X than on bike Y, all other things equal, is meaningless - no two passes through the event are the same at this level. Even at sprint distances (100m etc), world class athletes will report a range of experiences across several repeated attempts at the distance. Attempting to pin the 8 second gap that 1st place had over 2nd on his/her bike frame is ignoring a much simpler explanation: 1st place was generating more speed, regardless of the effect of the bike.
The point is that for a given power output on a given day, the “faster” equipment will make the rider faster than he would be otherwise. Those differences very easily can determine podium placings. You don’t need to have “two passes through the event”…that’s a total red herring.
If the positions and conditions are the same, a different bike or a different wheel or whatever isn’t going to change the power output. As one of the posters here on ST likes to quote me in his sig line: “Sometimes it’s about making the most speed out of the power you have.” Those absolute differences in equipment drag are a big part of what accomplishes that.
The point is that for a given power output on a given day, the “faster” equipment will make the rider faster than he would be otherwise. Those differences very easily can determine podium placings. You don’t need to have “two passes through the event”…that’s a total red herring.
I am not saying that your point about the effect of the frame is wrong. I am saying that there is a lot more noise in the data than is typically acknowledged, and the differences between the frames is small compared to the noise caused by the differences in power output, and position-dependent Cda. Ergo, you cannot get a fast frame and expect to be fast(er). You will be faster if you generate the same power with the same Cda, but the chances of you doing that (especially in non-test conditions) are small. You might get to a better watts/Cda spot, or a worse one, and the differences in that value likely dwarf the difference created by the frame. This means that the frame is helpful, but not predictive.
I’m saying that all those new bikes are so close in drag numbers that it doesn’t really matter which one you choose. I’m also saying that if all the bikes are correctly fit, even including the Centurion, that the variability of your performance will outweigh the variability of the bike’s impact on your Cda. Meaning, as I said to Tom, the bike is helpful, but not predictive. If you always ride XXX watts and maintain your Cda to within a very narrow margin, then the better bike will make you faster. Otherwise (which means most of us) you’re just going to have put in a better performance, whether by training, motivation, mental preparedness or whatever else gets you to the next level.
Oooooo…Biopace chainrings!
Anyway…I think gabbiev’s view is informative. While not any more or less valid than the original chart, it presents a different perspective on the data that may be useful if the variables in a particular athlete’s selection criteria. The engineer in me agrees that absolute differences are absolute. No argument there. But the racer in me knows also that it is absolutely impossible to say with certainty that an 8 second difference in performances corresponds exactly with an 8 second measured difference in frame aerodynamic drag performance. In other words…buy a frame (and other equipment) that gets you into the game…the rest is up to you. Don’t sweat too much over a frame that gives up a few seconds on some other frame. That isn’t going to cost you the race, particularly in multisport where it is a race to the finishline, not simply against a clock (as in TTs).
I think the inclusion of a reference bike such as the Centurion pictured…would provide additional perspective. And I suspect that it would not fall much appreciably over the other frames pictured, if at all. Some of the frames in the chart simply aren’t very aerodynamically effective.
I think gabbiev’s view also points out what a monumental effort the P4 is, if the data is indeed correct (and we haven’t seen anything to say otherwise). It has a clear advantage on the other grouping of frames. The other non-listed new designs like the Shiv, Giant, etc…may also be in that area with the P4. If so, the graph would then show a clear generational demarcation where frames DID get significantly more aerodynamic. If this is the case, then using my logic above…one might conclude that purchasing one of the “new generation” frames would be required to “get into the game”.