I got to do my first real test of the FIST position today.

The course: Canada road in Woodside CA - 1/4mile north of Jefferson to Hwy 92 & back. 10.13 miles with ~1000 feet of climbing.

Best recent "Low Diver" trial (5/8/07): 22:31 (26.99 mph) with 287 watts; pseudo-CdA:* .236

FIST trial (5/24/07): 22:29 (27.03mph) with 295 watts; pseudo-CdA* .245



*Pseudo-CdA takes air-density into account, but is calculated as if the course were flat. The true CdA for the Low Diver position in flat, windless conditions is ~.03 to .04 lower.


NOTES & QUALIFICATIONS: I suspect my power was significantly off today as I just got over a rather nasty case of bronchitis. I also blew my AWC on an earlier trial that I aborted when I dropped the chain. I would expect to gain another 5-10 watts in better circumstances.

There was a slight wind in both trials, which could easily bias the comparison. However, my experience with this course has been that the wind balances out unless it's real heavy.

What remains to be determined is how much of the power gain is due to raising the seat and how much to the slightly higher and much less extended aero-bar setup. I will hopefully find that out this weekend in side-by-side trials in real race conditions. I will also be doing more formal (0 wind) field testing trials to determine the actual cdA of each position.

This initial result is a little suprising. I was expecting both power and drag to increase more than they did.




-- jens