i know you don't actually think you are the ''norm'' (who does on this site anyway), but you are DEFINITELY not the norm. NARPs want data that tells them how much faster they will be over a distance in the easiest, most direct way possible.

...and "grams of drag" does that how?

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http://bikeblather.blogspot.com/

I know what you mean, but...

NARP = Non-Athletic Regular Person

That person doesn't care about speed or distance, except maybe the distance from their car to their goddamn barcalounger, where they can sit for over six hours each evening and let the cable TV wash over them

well, it translates (for most people) into seconds/k quite easily.

yea, so everyone slower than me. right?

I think that's what he meant. (This is just a random graph I grabbed off the internet to show what eisforurgent meant).

You're nothing if not consistent, Tom. But I like the way Mark Cote handled this question in 2008, which is to simply give Tom A. the data he wants separately from most everyone else

You're joking right? The entire triathlon industry is kept afloat by NARPs.

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"One Line Robert"

Any more easily than .01 m^2 CdA ~= 1s/km ~= 10W (at a wide range of race speeds)? I'd say "no".

And that's assuming you're sure at what test speed the "grams of drag" was measured of course. And if they don't specifically say it (such as on Cervelo's R5 website today), then you can't really be sure, can you? :-/

Here's the thing...most people have to be reminded of the "rules of thumb" for conversion anyway, so it doesn't really save anything to report in "grams of drag". The advantage of reporting in CdA is that IF someone DID want to do a more detailed analysis, they're ready to go. No other assumptions about the data are necessary.

Let me ask you this...what units of drag data do you think are used as inputs into prediction programs such as "Best Bike Split" and the like?

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http://bikeblather.blogspot.com/

Christ, Tom. Most people who will see this in Triathlete Mag cant even interpret what ^ is or means. Let alone that entire stretch of numbers and other special characters. You obviously don't get it. And then you launch into all this other shit - that again a NARP or a Fred just doesnt care about. And cant interpret anyway.

You're just pissed the industry wont bend to your will on how to report on such things. Much like your personal war against disc brakes. Its sort of odd really.

FURTHER - Kiley already said he'll give you what you want. Which is more than the bike industry has done to stop delivering disc brake bikes. What more do you want?

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"One Line Robert"

Not going to put error bars on the drag charts that compare all the bikes, just because it gets too busy and you can't actually see anything meaningful. That chart in the OP is hard enough to see as it is.

But there will be a lot of and maybe even an excessive amount of information on variability

Ummm...you might want to search around some more for where he and Chris Yu agreed that data should be reported in CdA.

If you'd like, I can show you the "standard" output spreadsheet from the Win Tunnel. Wanna guess what units it's in? ;-)

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http://bikeblather.blogspot.com/

What's actually "odd" is that you aren't answering my questions...and instead just attacking me. Ummm...OK.

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http://bikeblather.blogspot.com/

I'll answer.



Yes, absolutely.

In many cases here, I am discussing very small differences in drag. 0.01+ comparisons are in the minority. So then we start getting into 0.00x. What's easier to understand, 30 grams or 0.003?

This is the choice for the body of the report and in my opinion it's the right one for the audience. All of the main charts I can easily publish in CdA -- whether that's with the published report or after the fact I can't say. But you will get it eventually, I promise.

Isn't it chainrings, chain, cassette, front and rear derailleurs, and the assymetrical dishing of the rear wheel to accommodate freehub body? Perhaps one bike does a poorer job of normalizing that difference, somehow. Or a "better" job of amplifying it. Or yeah, an assymetry in the frame design itself.

Eye catching on the graph. And interesting how the Andean is the only bike which attempts to fair the chainrings, perhaps they fucked it up and accidentally directed loads of air onto the drive chain or something weird.

Negative x axis on a yaw sweep the drive side, right Kiley?

Nowt better than a bit of uninformed speculation! :-)

Actually now I'm looking closer at the P5x it almost forms a pocket around that area. Maybe it's the p5x!

Decimal points aren't hard to move. You want it in terms of .001 m^2 instead of .01? OK, that's ~0.1s/km. .003? OK, ~0.3s/km.

30 grams of drag? (at 30mph, right? Standard atmosphere? Just checking...)

Let's see...I know that ~0.1 lbs of drag (or, 45.5 "grams") measured at 30mph tunnel speed is ~equivalent to 0.5s/km of time difference. 30/45.5 = ~2/3....2/3 of 0.5s/km is ~0.33s/km...yeah, that's SO much easier :-/

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http://bikeblather.blogspot.com/

Cervelo was 1,460

The kink in #6 tells me it's a disc bike. I'm going to go with a somewhat unpopular view:

6. P5-X
5. Diamondback Andean
4.
3.
2. P5
1. Premier Tactical

Edit: I'd like to add that there's a chance that the Ventum is #6. I've been told by two people that the Ventum "isn't great" at yaw but I can't think of why it would do well on the drive side and poorly on the NDS.

Can't edit for some reason. I mixed up DS and NDS. Also the rear wheel could contribute to the asymmetry.

I think it would be amazing if Premier came in from nowhere and not only undercut the price of all of the other bikes (they did already) but also beat them aerodynamically as well. Personally I think it's the best looking of the bunch as well.

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--Chris

I'm thinking along the same lines. The asymmetry in 6 suggests it's a bike with disc brakes and the p5x has the worst integration with brakes that appear to have been an afterthought. Then, Kiley has already suggested he's going to sell his Andean after this season and I can't help but think that the test results here may be a factor. So I'm leaning towards 6 and 5 being P5X and Andean.

I think there have been hints of the Premier Tactical being surprisingly good - there's also a fairly consistent presence of Dan on this forum which makes me think he's very excited about this. Kiley has also been very positive about the Tactical... so it must be scoring well. The P5 has always been considered to be on of the best... so I would expect it still is. So I'd agree with the top 2 as well.

It would definitely be cool to see the cheapest bike be the fastest and the most expensive bike be the slowest. That's going to create some animated discussion if that would be the case.

OMG only on ST would someone argue that "grams of drag" is easy for the masses to understand.

So the rule of thumb is valid if you are riding at 30 mph. How does one get that rule of thumb converted to say 24 or 25 mph?

What most people seem to be doing when analyzing these type of things is that they get to xx amount of watt savings. Let's say its 10 watts saved (at 30 mph) but they ride at 23-24 mph. Then they guess and say its more like 8 watts at their riding speed.

I'm with Tom on this one but I understand why it's being published in grams of drag. Sign me up on the list for someone who would like to see CdA data.

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blog

I'm saying that I hope that the measurement uncertainty around each data point is included. Otherwise, we can't make statements around statistical differences/significance from just visualizations of the point-estimate data from each bike.

Who's doing the statistical analysis? I'm sure they'll take this into account, pretty stats-101 stuff