TT bike race setup (kind of)

[turbomentor]

Attached is my ride file from the White Lake Half 70.3 triathlon on Saturday. I have an iAero on my TT bike (Cervelo P3C) and I'm using the Remote Wind Sensor (RWS). I hit the lap button at 14 miles, 28 miles, 42, 49 and 56 miles.

I use a PT in conjuntion with my iAero and I always find it instructive to compare data. The PT showed a Pavg of 200W, the iAero 191W (within 4.5%). The first lap iAero was -1W of the PT and lap 2 it was -2W of the PT. I'm looking over my data to try to figure out why, but on the 3rd 4th and 5th laps, the iAero was 11-12W of the PT (within about 6%). I'm sure there is a reasonable explanation of why it was so "on" for 28 miles and a bit "off" for the remaining 28 miles.

In any case, the RWS works exceptionally well. I've been using it for about a month and a half now and it has performed great. I redid my profile ride the day before the race to reflect some major changes in my setup (aero helmet, rear wheel cover and RWS) and the profile I generated produced the data shown in the ride file.

If you open the ride file, you'll see numerous little "hits" on the final hour or so of the ride where I had to sit up and adjust my tri shorts... I was wearing a new pair of shorts and they are not yet "broken in" for longer rides!

[Steve_Davidson]

Attached is my ride file from the White Lake Half 70.3 triathlon on Saturday. I have an iAero on my TT bike (Cervelo P3C) and I'm using the Remote Wind Sensor (RWS). I hit the lap button at 14 miles, 28 miles, 42, 49 and 56 miles.

I use a PT in conjuntion with my iAero and I always find it instructive to compare data. The PT showed a Pavg of 200W, the iAero 191W (within 4.5%). The first lap iAero was -1W of the PT and lap 2 it was -2W of the PT. I'm looking over my data to try to figure out why, but on the 3rd 4th and 5th laps, the iAero was 11-12W of the PT (within about 6%). I'm sure there is a reasonable explanation of why it was so "on" for 28 miles and a bit "off" for the remaining 28 miles.

In any case, the RWS works exceptionally well. I've been using it for about a month and a half now and it has performed great. I redid my profile ride the day before the race to reflect some major changes in my setup (aero helmet, rear wheel cover and RWS) and the profile I generated produced the data shown in the ride file.

If you open the ride file, you'll see numerous little "hits" on the final hour or so of the ride where I had to sit up and adjust my tri shorts... I was wearing a new pair of shorts and they are not yet "broken in" for longer rides!

By the looks of things in the file the main difference is the apparent wind so my guess is more of a cross wind on later laps thus dropping the iAero dynamic pressure and showing up as an overall average tailwind for the sectors in question.

Steve

[ludlaw]

Where is your iBike mounted on your tt bike? Did you do coast downs to obtain crr and cda or did you use your PT? Before you used the remote wind sensor were you able to get accurate numbers?

I have been able to get my PT and my iAero to read very close to one another on my road bike (stem mount) but have been having a hard time getting the numbers anywhere close on my tt bike. Frustrating.

[turbomentor]

Where is your iBike mounted on your tt bike? Did you do coast downs to obtain crr and cda or did you use your PT? Before you used the remote wind sensor were you able to get accurate numbers?

I have been able to get my PT and my iAero to read very close to one another on my road bike (stem mount) but have been having a hard time getting the numbers anywhere close on my tt bike. Frustrating.

In the TT thread there are pics of my setup.

I have the iAero mounted on my stem. Since I'm a triathlete (not a TT bike rider) my aero bars are not excessively close together. As a result, the wind port had a good clean look at the incoming air and I did in fact get good data.

I can tell you categorically that the Remote Wind Sensor is both very simple to use and very effective. It simply moves the wind port to wherever you want on your bike, making placement of the iBike irrelevant.