Based on my initial testing, the P3C is worth more than 10 watts over the P5. The bikes are set up almost identically, with one major difference: the P3C has a 1X setup with a q-factor of 121 (vs. 149 for the P5).
That brings my legs in nearly 3 cm closer, an aero advantage that overwhelms the P5’s enhancements over a stock P3C. I hope to improve on this by eliminating the R. Derailleur cabling with e-tap and by switching to a more aero rear brake.
When all is said and done, I’m hoping to see a ~15 watt advantage for the P3C. I’ll be putting my P5 in the classifieds in the next few weeks.
To make this all work I had to find this puppy:
It is an extremely rare 150 mm Campy track crank. Even a slightly longer crank would not clear the chainstays:
With a narrow BB, I do have to accept a slight asymmetry – the drive-side crank is about 8 mm further outboard than the non-drive side. So far this has not been a problem – maybe because it compensates for a slight leg length discrepancy I have.
So you’re attributing a massive swing from P3 to P5 (the P5 was originally stated as being what…10w faster than P4 or P3?) to a narrower Q factor and an Omega X front brake?
So you’re attributing a massive swing from P3 to P5 (the P5 was originally stated as being what…10w faster than P4 or P3?) to a narrower Q factor and an Omega X front brake?
Looking at the bottom picture makes me wonder how your heels clear the chainstay and rear skewer. Are you super pigeon-toed? I set my cleat spacing to be almost as narrow as it will go with the short axle SpeedPlays and my heels would hit both the stay and the axle on your bike.
So you’re attributing a massive swing from P3 to P5 (the P5 was originally stated as being what…10w faster than P4 or P3?) to a narrower Q factor and an Omega X front brake?
How much frontal area area does a frame have?
How much frontal area do your legs have?
his q factor doesn’t really seem to be influencing his FA as it relates to his quads and hips.
his q factor doesn’t really seem to be influencing his FA as it relates to his quads and hips.
Forget about that specific photo. Just compare the width of your calves and ankles to the width of your frame. **Each **of my skinny calves is 3-4X wider than my frame. Multiply that by an average length of 26 inches and it’s significant.
Are you super pigeon-toed?
Well, moderately. The narrower q-factor actually has an ergonomic benefit for me because of that.
Cool Jens. It reminds us that the number one most important feature of the bike frame is how your body fits to it.
Question from someone who doesn’t know much about the P3C: what makes this possible on a P3C and not possible on the P5?..something about the BB?..or maybe frame clearance for the crank?
The P3 has a threaded BB, which allows him to run an older-design, narrow square-taper BB. The P5 has a press-fit BB that only works with modern, integrated-axle cranks.
One of the of the other improvements I’m planning is to switch to a USE tula bar or aero-or-die. Neither of these would be possible with the P5 – unless I replaced the Magura brakes, which would be a big pain.
