Friday, July 4, 2008

PCs, day 2

Did a quick 30 minute "easy" ride this morning. Was planning to do 60 minutes, but I noticed my perceived effort was way too high. I'm planning on racing track tonight so I didn't want to wear myself out. The PCs really force me to push, so recovery rides with them are a challenge. Currently I don't have either of my Powertap wheels on the training bike (one on the TT bike, the other on the race bike, and I'm too lazy to swap out cassettes today), but I was wearing a heart rate monitor. Normal practice for me is to ride without heart rate, but when I don't have power, it's a nice feedback. I know how my power zones correlate to my heart rate zones in the absence of cardiac drift due to heat/dehydration. My heart rate was much too high for a recovery ride. My threshold is in the 270 W range (~4 W/kg), and heart rate typically is in the upper 150s/lower 160s for that power. With the PCs, I was trying to take it easy (but kept accelerating) and was in the 130s.

I did a completely unscientific test where I cycled one loop of a neighboorhood block on both my training bike with PCs and race bike with normal cranks. Times were identical. Perceived effort was higher with the PCs, and my heart rate for the loop was a consistent 15-20 bpm higher with PCs. That 15-20 bpm equates to around 40-50 watts for me. That's too much to be accounted for by rolling resistance (virtually identical tires) and aero (was on the tops on both bikes).

Next week or as soon as I get back from Japan, I'll do some back-to-back testing on the two bikes again, but this time with power.

Time on PCs - 30 minutes
Year to day - ~65 minutes

No comments: