Wednesday, February 03, 2010

Cervelo: P3 vs P2K

I moved all my components over from the P2K frame to the P3 frame and did another round of Chung testing.  I'm not surprised at the results - the frames are identical except for the seat tube and seat stay shapes.

My average of three Chung test days on the P2K was CdA=0.231.  My CdA on the P3 was measured today at 0.232 in perfect, calm conditions - very clean data.  At least I'm finding the method consistent; and apparently I did a good job of getting my setup the same on the P3 as on the P2K (most drag is the result of body position).

Any changes from here on out will be with body position.

8 Comments:

gregclimbs said...

that doesn't sound right... typo?

g

Robert Jordan said...

Yes - typo - thanks for pointing that out. I didn't think I was dyslexic, but....

gregclimbs said...

I still have a hard time finding that the p3 tested slower than the p2k unless the position transfer was not 100% correct :D

g

Robert Jordan said...

Well, I'm not saying the P3 is slower; but it appears that my testing results, which seem to have a CdA standard deviation in the 0.004 range, did not measure any discernable difference. It's always possible that there was some significant frame drag improvement and that it was drowned out by some unknon body position difference between the two. But there is so little difference between those two frames that maybe measuring it is just beyond the capability of my Chung testing. I'll probably never know.

Robert said...

" I'm not surprised at the results - the frames are identical except for the seat tube and seat stay shapes."
Is this a new P3?

Robert Jordan said...

No, the P2K and P3 I'm comparing are both 2002 or 2003 aluminum frames.

Robert said...

Ah! OK, I thought you were comparing a P2K with the new P3.

Anonymous said...

Like Greg, I am also surprised that you couldn't detect any difference between a P2k and a P3.