Speed difference for a 40k between P2 and P3? (Page 2)

If you have to ask... you can't afford it.

This type of question usually stems from, "should I shell out the extra green for the P3 or is the P2 sufficient?"  If you're not shopping for a top-end QR or Felt or Scott or P3 because you have the green to buy ANY of those bikes - don't ask.  If money is an issue, then I would say the obvious answer to your question is, "not enough time savings to warrant the extra cost of the P3.  Go with the P2."

But if you're always racing for the podium and need every ounce of speed you can squeeze from your equipment, then you just have to decide if you're willing to pay for it.

It has actually more to do with how well the bike fits. The P3C has a longer top tube and lower front end that is more evident in the larger sizes, better for riders with a longer torso. The P2C is more proportionate with a higher front end. So for the same rider on the same course, he might actually be a little faster on the P2C if that bike fits him better. It makes no sense to only take the frame into consideration because when you race it's always you on the bike, so frame + fit is the way to go. The latter being more important.

Check out this review for the P2C:

https://www.bikesportmichigan.com/reviews/cerveloP2C2008.shtml  

I'm looking for a new bike so this is a great post.

I talked to John Cobb a few weeks ago and he said since  I didn't have good flex then a short headtube would be better for me and as Michael said the P3C had a shorter head tube than the P2C. While others are saying that you need to be more flexible for the P3C. Sounds like some mix information. Where is Patel when you need him ?

But how aero is the coconut?

I have never heard that you want a shorter head tube if you have less flex.  That is totally counter intuitive to everything that I know (I am no expert so please put me in my place if I am out of line here).

I just got fit for my new P2C and left the stem all the way up (spacers under the stem, longer head tube).  I have good power, good aero position and my neck doesn't hurt too much on long rides.  As I get more flexible (neck feels comfortable looking forward and my legs can still create power up near my gut) I will lower the stem (shorter head tube).  As I get more and more flexible and can create power with my knees all the way up in my gut I will continue to shorten my head tube by removing the spacers.  I have no idea how far I will be able to go or how long it will take (time will tell).

The P3C with the shorter headtube wouldn't let me start as high as I am currently and I might find that I couldn't stay in the aero position as well or as long because my neck hurt from looking forward and my legs didn't have the power being right up in my gut.   This is a more agressive position but not one that my body is ready for yet.

Michael