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Re: The official Cervelo P5 thread [damon_rinard] [ In reply to ]
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Hi Damon,

Thx for the swift reply, P5 is already ordered but in march or so i'm on the market for that power meter Sram Red Quarq.

About which Sram Red group it'll be, it prolly has to be the Sram Red 2012 Yaw group.
As Sram Red Quarq power meter is only compatible with the Sram Red 2012 Yaw front derailleur.

Do correct me if i'm wrong ;-)

Greetz

2016 Schedule:
IM South Africa - Challenge Roth - IM 70.3 Zell am See - Marathon Valencia
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Re: The official Cervelo P5 thread [Axolotl] [ In reply to ]
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Hi Axolotl,

SRAM Red is only "officially" compatible with the Yaw front derailleur.


Slowtwitcher "veryoriginal" has installed the SRAM Red Quarq crank on his BBright Cervelo S5 with Di2. Photo above from his post:
http://forum.slowtwitch.com/...rum.cgi?post=3992861

For Yaw compatibility, see VeloNews: http://velonews.competitor.com/...compatibility_209270
Basically, the chain rings work with other front derailleurs too.

It's definitely compatible with BBright. This crank is the "BB30" variant from SRAM. It's natively compatible with BBright; just replace the left side threaded adjuster with a single wave washer (and maybe a few very thin plastic washers).

Cheers,

Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)
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Re: The official Cervelo P5 thread [damon_rinard] [ In reply to ]
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Thx Damon,

Seems quite good!
The only thing i'm wondering now is which Sram Red it'll be on the P5, and which shifters it'll use.
Propably upgrading these to the new R2C shifters if they aren't provided.

2016 Schedule:
IM South Africa - Challenge Roth - IM 70.3 Zell am See - Marathon Valencia
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Re: The official Cervelo P5 thread [Axolotl] [ In reply to ]
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Hi Axolotl,

Good news: The P5 will come with the newest SRAM Red, 100% compatible with Yaw chain rings.
Also the shift levers are R2C.

Enjoy your new P5!

Cheers,

Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)
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Re: The official Cervelo P5 thread [damon_rinard] [ In reply to ]
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This news made my day!!!

2016 Schedule:
IM South Africa - Challenge Roth - IM 70.3 Zell am See - Marathon Valencia
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Re: The official Cervelo P5 thread [damon_rinard] [ In reply to ]
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Damon

I have a 56 with the x-low installed.

I now am unable to get my bar into uci legal position to far from center of BB

Is there a shorter stem version of the 3T bar?

Thanks for the help and info.
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Re: The official Cervelo P5 thread [MaxApp] [ In reply to ]
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Hi max,

I assume you're talking about the 75 (or 80) cm rule for the extensions?
Should work with straight, J-bends and other shape extensions, but not always with S-Bends.

We accept this exclusion based on wind tunnel testing a bunch of pros, including comparing performance of different extensions.

Does this answer your question?

Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)
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Re: The official Cervelo P5 thread [damon_rinard] [ In reply to ]
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Damon:

I use Hed Lazy S this in wind tunnel tested.

So there is no second size stem?

thanks again
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Re: The official Cervelo P5 thread [MaxApp] [ In reply to ]
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Hi Max,

No sorry, only one Aduro base bar.

I'm really happy to hear you've gone to a wind tunnel! Which one? At Cervelo we always acknowledge the rider is the biggest drag, and a good wind tunnel can make almost everyone faster.

I assume you've already considered cutting the length? We use this rule of thumb: the shifter axle should be near the knuckle of the middle finger. This is shorter than a lot of people; it puts most of the lever inside your hand. Maybe it could bring your bike into comformance?

Cheers,

Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)
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Re: The official Cervelo P5 thread [damon_rinard] [ In reply to ]
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Damon

Its the stupid rule for the return to center shifters.

UCI is killing our sport...........................................
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Re: The official Cervelo P5 thread [MaxApp] [ In reply to ]
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Ah. Yes.

Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)
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Re: The official Cervelo P5 thread [damon_rinard] [ In reply to ]
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Damon:

I posted my best TT ever on my P5 the first race after getting it.

I posted a 29.28 MPH on 319 watts. I've just got to figure out the over 80 cm issue so that I can compete at nationals. Of course my best friend won the 45+ national TT on his P5 this year.

This is an amazing tool for speed. I had the P3, P3C, first gen P4, P4 Evo which is the most under rated frame ever and now the P5. You guys have offered great support all along the way.

Keep it up!
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Re: The official Cervelo P5 thread [damon_rinard] [ In reply to ]
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Damon,

Can you comment some more on the drag comparisons between the S5 vs P5 from the white papers. It appears at first blush that the S5 is faster, if one set it up in TT mode.
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Re: The official Cervelo P5 thread [jeffp] [ In reply to ]
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Hi Jeff,

You might be thinking of when we compared an S5 versus a P4.

Of course the different stack & reach between a road bike and tri bike are best suited to different riding positions. So to compare the *bikes,* not positions, for this comparison we kept the same riding position: bars as low as possible on the S5, and the same fit coordinates on the P4 (higher bars than most folks would ride a P4).

In this comparison the S5 was essentially tied with the P4.

Of course, with a better riding position (lower bars), the P4 was faster than the S5.

And later we developed the P5, which is faster than the P4.

So we've never actually made a direct comparison between the S5 and P5, but if you're willing to use the P4 as a "link" between the two then the P5 is faster than the S5.

Cheers,

Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)
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Re: The official Cervelo P5 thread [damon_rinard] [ In reply to ]
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No, Tom A mentioned that, but I was just referring to the tunnel data(albeit from different tunnels it seems)for the P5 and the S5 in their respective white papers on your website. I assume it is the different tunnel that is the reason why the S5 looks better in road position than P5 does in TT position, or is one of the plots wrong?
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Re: The official Cervelo P5 thread [jeffp] [ In reply to ]
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Hi Jeff,

Thanks, I see what you mean now. Yes, as you mentioned the different tunnels mean the data can't be compared directly.

Cheers,

Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)
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Re: The official Cervelo P5 thread [damon_rinard] [ In reply to ]
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so a 48 with an 11 or 12 stem, saddle slammed all the way forward and I have my current TT bike sans horizontal dropouts :)

my 51 non-cervelo frame runs a 7cm stem (S-R 515-391) just thinking out loud(bad idea for me in general)
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Re: The official Cervelo P5 thread [damon_rinard] [ In reply to ]
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damon_rinard wrote:
Hi Jeff,

Thanks, I see what you mean now. Yes, as you mentioned the different tunnels mean the data can't be compared directly.

Cheers,

Since the guys at the LSWT told me that they typically DO NOT subtract the fixture drag, I'm thinking the reported P5 drag values are slightly high? Do the S5 numbers taken at the UW tunnel include tare or is it subtracted?

So tell me...aside from whether or not the fixture tare is included or not, it would be easier to compare between tunnels if the results were reported in terms of CdA, no? ;-)

http://bikeblather.blogspot.com/
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Re: The official Cervelo P5 thread [jeffp] [ In reply to ]
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jeffp wrote:
so a 48 with an 11 or 12 stem, saddle slammed all the way forward and I have my current TT bike sans horizontal dropouts :)

To be honest, I don't miss the horizontal dropouts of a dedicated TT/Tri rig :-)

http://bikeblather.blogspot.com/
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Re: The official Cervelo P5 thread [Tom A.] [ In reply to ]
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they are easy enough to deal with if you know what you are doing, which you do. one wheel change is 10sec, the other 15 relatively speaking
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Re: The official Cervelo P5 thread [jeffp] [ In reply to ]
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jeffp wrote:
they are easy enough to deal with if you know what you are doing, which you do. one wheel change is 10sec, the other 15 relatively speaking

Understood...and I know the technique...however, I did find that SRAM derailleurs were less "amenable" to the manipulation required to get a wheel out of a horizontally dropped bike. I had NO issues at all with Shimano rear derailleurs BTW.

I'm just sayin' I don't miss struggle with the horizontal dropout/SRAM combo...and I don't think I'm really "giving anything up" by not having it on the S5.

http://bikeblather.blogspot.com/
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Re: The official Cervelo P5 thread [Tom A.] [ In reply to ]
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appears not

never had sram RD, so I kno wnot of that which you speak, but will take your word for it.

how about the S5 as a track pursuit bike :)

oops, wroong thread for that
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Re: The official Cervelo P5 thread [Tom A.] [ In reply to ]
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Hi Tom,

Good guess, but it's not the fixture drag per se, as we tare and subtract that; there are probably slightly different fixture interactions though. This is another plus for us when using CFD: Just like in real life, there's no holding fixture in CFD. (Unless we want to include it.)

There are many small but significant differences between any two wind tunnels. Like Chuck Zimmer used to tell me when I was a young associate engineer at GKN Aerospace: "As usual Damon, it's more than one thing!" So far it's just been easier for us to compare results from the same tunnel.

As for CdA, point taken. But the balance actually measures the drag force, and we report the drag force; CdA would be subsequently calculated from that, so I'm not seeing how it would allow us to compare results from different tunnels any better. Drag force is just what we work in; my mind is more used to it (I hope that doesn't mean I'm getting old! LOL).

Cheers,

Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)
Last edited by: damon_rinard: Nov 9, 12 10:00
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Re: The official Cervelo P5 thread [damon_rinard] [ In reply to ]
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damon_rinard wrote:


Good guess, but it's not the fixture drag per se, as we tare and subtract that; there are probably slightly different fixture interactions though. This is another plus for us when using CFD: Just like in real life, there's no holding fixture in CFD. (Unless we want to include it.)


Yeah, if only someone made a real-time wind sensor (speed and direction) so that these measurements could be taken outside ;-)

damon_rinard wrote:
As for CdA, point taken. But the balance actually measures the drag force, and we report the drag force; CdA would be subsequently calculated from that, so I'm not seeing how it would allow us to compare results from different tunnels any better.


Except, drag force alone means little without the context of air density and wind speed. In other words, reporting CdA is taking that context into account and giving you a single number.

Here's the thing...if the CdA of an object isn't consistent across tunnels, then doesn't that play to the arguments of those who say that wind tunnel measurements don't reflect "reality"?

damon_rinard wrote:

Drag force is just what we work in; my mind is more used to it (I hope that doesn't mean I'm getting old! LOL).


Of course it does :-P ...and your reasoning is the same one that is going to prevent the US from switching over to the metric system. I just saw an article on this subject just this past week...no generation wants to be the one to have to do the conversions in their head! ;-)

edit: found the blog post http://www.mobilehydraulictips.com/...the-imperial-system/

http://bikeblather.blogspot.com/
Last edited by: Tom A.: Nov 9, 12 11:30
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Re: The official Cervelo P5 thread [7summits] [ In reply to ]
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Hi,

Great looking bike. I was wondering if you would share more on your preference of the new Sram Red w/R2C shifters over mechanical DA. I've got a P5-three on it's way and I'm trying to decide which mechanical group to go with--can't quite swing Di2 in the budget.

If it's easier, please send a pm with your thoughts.

Thanks!
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