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Cervelo P2C vs P2SL/P1 drag data? How do they compare?

Ryon

Oct 27, 09 18:25

Post #1 of 16 (654 views)

Cervelo P2C vs P2SL/P1 drag data? How do they compare?	Can't Post

Hi Everyone

I'm looking to upgrade my frame from a Leader 720TT (alu, all round tubes minus the downtube) to either a Cervelo P2C or Cervelo P2SL (now known as the P1).

I'm curious to see if there is any hard drag data out there comparing these two frames, or on the P2SL in general. I know there was a thread comparing the P2K and the P3C a while back via an outdoor velodrome and a power meter. Through that thread was interesting, it was riddled with caveats, and it's difficult to establish any hard comparisons.

For me:

$$ is an issue.
Comfort is NOT an issue.
Speed is THE issue.

The selling point for me will be how closely (or not) the two frames would perform.

Thanks for reading! I'd appreciate any input you might have.

Ryon
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What Would Jens Do?

RChung

Oct 27, 09 18:50

Post #2 of 16 (636 views)

Re: Cervelo P2C vs P2SL/P1 drag data? How do they compare? [Ryon] [In reply to]	Can't Post

In Reply To:

I know there was a thread comparing the P2K and the P3C a while back via an outdoor velodrome and a power meter. [Though] that thread was interesting, it was riddled with caveats, and it's difficult to establish any hard comparisons.

If you think that comparison was riddled with caveats and difficult to make conclusions from, well, good luck with what you do find.

Ryon

Oct 27, 09 19:31

Post #3 of 16 (608 views)

Re: Cervelo P2C vs P2SL/P1 drag data? How do they compare? [RChung] [In reply to]	Can't Post

not to knock that test too much (perhaps I was a little harsh), but I was hoping to find something like this:

or something similar. But hey, I'm a PhD student. It's my job to analyze data and design experiments. (and is also why $$ is an issue. lol.)
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What Would Jens Do?

(This post was edited by Ryon on Oct 27, 09 19:32)

Cat6

Oct 27, 09 19:34

Post #4 of 16 (599 views)

Re: Cervelo P2C vs P2SL/P1 drag data? How do they compare? [Ryon] [In reply to]	Can't Post

The P2sl is the same as the P1 and as far as aerodynamics go...the P2C is probably a little more aerodynamic...but the P2SL/P1 is WAYYY cheaper.

RChung

Oct 27, 09 20:07

Post #5 of 16 (577 views)

Re: Cervelo P2C vs P2SL/P1 drag data? How do they compare? [Ryon] [In reply to]	Can't Post

In Reply To:

not to knock that test too much (perhaps I was a little harsh), but I was hoping to find something like this: [snip]

or something similar. But hey, I'm a PhD student. It's my job to analyze data and design experiments. (and is also why $$ is an issue. lol.)

If you think those conclusions are clear then you haven't been following the reports on wind tunnel comparisons.

But hey, I'm a professor who teaches PhD students and it's my job to teach them how to analyze data and design experiments.

Ryon

Oct 27, 09 20:17

Post #6 of 16 (563 views)

Re: Cervelo P2C vs P2SL/P1 drag data? How do they compare? [RChung] [In reply to]	Can't Post

I owe you an apology. I wasn't aware of this thread:

http://forum.slowtwitch.com/...t_reply;so=ASC;mh=50

I was referring to another field test.

I admit that I am fairly new to slowtwitch and I am not up to date in the latest wind tunnel comparisons. Hence why I started this thread.
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What Would Jens Do?

RChung

Oct 28, 09 7:02

Post #7 of 16 (458 views)

Re: Cervelo P2C vs P2SL/P1 drag data? How do they compare? [Ryon] [In reply to]	Can't Post

In Reply To:

I owe you an apology. I wasn't aware of this thread:
http://forum.slowtwitch.com/...t_reply;so=ASC;mh=50

I was referring to another field test.

I admit that I am fairly new to slowtwitch and I am not up to date in the latest wind tunnel comparisons. Hence why I started this thread.

No apology necessary (though, for future reference, it's really not too wise to write stuff like, "But hey, I'm a PhD student. It's my job to analyze data and design experiments.")

Wind tunnels may be more precise than field tests (and, of course, they let you test at controlled yaw) but they still require some interpretation -- and sometimes the interpretation is both demanding and subtle. And, as has recently been demonstrated in another thread, cross-tunnel comparisons of the same items ain't a piece of cake. I'll repeat what I wrote above: if you think that the field tests comparisons discussed on ST are riddled with caveats and difficult to make conclusions from, well, good luck with what you do find.

jackmott

Oct 28, 09 7:15

Post #8 of 16 (440 views)

Re: Cervelo P2C vs P2SL/P1 drag data? How do they compare? [RChung] [In reply to]	Can't Post

look, its simple

the p2c has aero seat stays

the p2sl does not

thats gonna cost you thousands of milliseconds per 40k

;)

and the non formed head tube, another thousand or two
----
Sunglasses: http://www.framesdirect.com/sunglasses
Tri Gear: http://www.atctrishop.com
rear wheel disc ALWAYS http://www.wheelbuilder.com if poor front wheel whatever torodial rim wheel you want, or H3. deeper if yer faster shallower if yer slower tires - http://www.biketechreview.com has crr data, use it frames - position trumps aero trumps weight trumps paintjob trumps stiffness water bottle between your arms or not at all if its a sprint swimget some swim lessons, its cheaper than buying bike speed train more and HTFU

Andrew Coggan

Oct 28, 09 8:40

Post #9 of 16 (416 views)

Re: Cervelo P2C vs P2SL/P1 drag data? How do they compare? [RChung] [In reply to]	Can't Post

In Reply To:

If you think that comparison was riddled with caveats and difficult to make conclusions from, well, good luck with what you do find.

Actually, it would appear that Ryon was referring to this thread:

http://forum.slowtwitch.com/...post=1344248#1344248

in which case I would say that he is right. As he later discovered, though, Tom A. subsequently performed a more formal comparison, as did I:

http://forum.slowtwitch.com/...post=2072602#2072602

Ryon

Oct 28, 09 10:22

Post #10 of 16 (365 views)

Re: Cervelo P2C vs P2SL/P1 drag data? How do they compare? [Andrew Coggan] [In reply to]	Can't Post

In Reply To:

If you think that comparison was riddled with caveats and difficult to make conclusions from, well, good luck with what you do find.

That's thread that I saw! My main criticism would be the slightly different gear use, like the helmet and shoe covers, etc... Not everyone has a velodrome nearby, but it was pretty cool to see.

Like I said, I'm fairly new to slowtwitch, so I'm not really up to date on all of the independent testing that people have done here. Curious, has anyone looked at how the Equinox compares to the TTX or to one of Cervelo's frames? I've been told that the Equinox has a very similar drag contribution as would be for the TTX. Depending on how much you like the wind tunnel testing, the TTX seems to stack up pretty well. So, it makes me wonder regarding the battle of the aluminum frames. Equinox vs. Alu P1 (p2K, P2SL)?
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What Would Jens Do?

Andrew Coggan

Oct 28, 09 10:52

Post #11 of 16 (339 views)

Re: Cervelo P2C vs P2SL/P1 drag data? How do they compare? [Ryon] [In reply to]	Can't Post

In Reply To:

That's thread that I saw! My main criticism would be the slightly different gear use, like the helmet and shoe covers, etc...

Keep in mind that it wasn't a planned experiment, but a post hoc comparison of data collected 5 y apart.

In Reply To:

Not everyone has a velodrome nearby

Unfortunately, neither do we (if we did, my wife would probably still be racing).

In Reply To:

Curious, has anyone looked at how the Equinox compares to the TTX or to one of Cervelo's frames?

I don't recall seeing anyone post any independent data here (or elsewhere) for the Equinox.

TheDC

Oct 28, 09 11:18

Post #12 of 16 (316 views)

Re: Cervelo P2C vs P2SL/P1 drag data? How do they compare? [Ryon] [In reply to]	Can't Post

I think most will agree that the P2 is "faster" than an equally equipped P1. The question is: does the price difference between the P2 and the P1 justify in your mind the aero advantages. Also could the money you save buying the P1 be better spent elsewhere like a wheel cover and a deep front wheel and an aero helmet. What you lose in aero between the two frames you may end up recouping more in better accessories on the cheaper bike.
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�The Edge... there is no honest way to explain it because the only people who really know where it is are the ones who have gone over. �

"When the going gets weird, the weird turn pro."
Hunter S. Thompson (1937-2005)

Ryon

Oct 28, 09 11:53

Post #13 of 16 (282 views)

Re: Cervelo P2C vs P2SL/P1 drag data? How do they compare? [TheDC] [In reply to]	Can't Post

In Reply To:

That's very good advice. I probably should have mentioned in my original post that I have a rear disc (renn575) and an 88mm deep front wheel (easton knock-off). Or better yet, i should have posted a pic of my ride...

context: San Diego TTT

Granted, I'll also be looking to get a more slippery aero cockpit as well. I've got about $1K to spend on improvements on my TT setup for next season. Which is why an aluminum Cervelo or perhaps an alu Equinox frame are fairly attractive to me.
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What Would Jens Do?

Ryon

Oct 28, 09 13:13

Post #14 of 16 (258 views)

Re: Cervelo P2C vs P2SL/P1 drag data? How do they compare? [Ryon] [In reply to]	Can't Post

essentially, I'm pretty sure most frames would be faster than the one I have.
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What Would Jens Do?

Boudreaux

Oct 28, 09 13:25

Post #15 of 16 (244 views)

Re: Cervelo P2C vs P2SL/P1 drag data? How do they compare? [Ryon] [In reply to]	Can't Post

Yer seat's too high....

"you know, aero trumps training ;-) "
R10C 10/09

bikerbrian

Oct 28, 09 17:16

Post #16 of 16 (189 views)

Re: Cervelo P2C vs P2SL/P1 drag data? How do they compare? [Ryon] [In reply to]	Can't Post

you should be in your aerobars instead of sitting up. Until you fix that stick with your current frame.

I'd get the P2c just because I like fact that it has a down tube mounted water bottle mount and I think it looks nicer:) That said, I have a P3c and love it.

"Oh you hate your job? There's a support group for that, it's called EVERYBODY and they meet at the bar."