Profile Building: 2 Bikes, 3 Wheelsets, PowerTap

[Norm]

I have 2 bikes, and 3 wheelsets (climbers, aero's, and PowerTap sets) and I'm wondering what shortcuts (if any) I can use in building the profiles. I ride the following setups:

1) TT bike + aero wheels
2) TT bike + aero front + PT rear
3) TT bike + PT wheels
4) road bike + climbers
5) road bike + aero wheels
6) road bike + PT wheels

Am I really stuck building out all 6 profiles? As I change out wheelsets, riding position won't change, but aero and rolling resistance will. I intend to use the same tires on all three wheelsets.

The climbers (Kysrium SL's with ceramic bearings) and the PT's (OpenPro's) might wind up being close enough to use the same profile.

Any ideas?

[Norm]

In another thread, coachboyd writes:

Re: A weight question
by coachboyd on Fri Feb 20, 2009 12:21 am

If you have a Gen 3 unit, you won't have to redo your cal ride. The cal ride just stores wind scaling and riding tilt in the unit. Those values are what makes it possible to get cda and crr from the aero and friction values.

So, you can just do a bunch of coastdowns, and use the previous stored wind scaling and riding tilt numbers and you will have a new profile! Wind scaling and riding tilt won't have changed, well riding tilt might have slightly but if you get a good crr number then you are good. Riding tilt is not as important as it used to be because of the tilt correction, but it is used in determining crr from the friction number. So as long as your crr is good, then your riding tilt can be slightly off.

So... it sounds like I could do something like this:

1) Road bike + PT wheels: 4-mile ride => Profile 1
2) Road bike + climbers: coastdowns + 4 mile ride from step 1 => Profile 2
3) Road bike + aero wheels: coastdowns + 4 mile ride from step 1 => Profile 3

thus generating all 3 profiles from a single 4 mile ride and 2 sets of coastdowns. Is this correct?

[coachboyd]

That should be right. As long as you don't move the iBike from where it's positioned the wind scaling should stay the same. Riding tilt might change very very slightly, but nothing to be concerned about, especially with the self correcting tilt.