Choosing the right wheel size in my cycle computer I have bought the Campangolo Khamsin wheelset, and now I would like to set the right wheel size in my Trek Incist 8i cycle computer. Before I do the custom wheel setting, I would like to know what would be the best choice?  

The wheel has ETRTO 622x15c printed on it. 

The computer comes with the following wheel sizes defined:

700x20, 700x23, 700x25, 700x28, 700x32, 700x35, 700x38, 26x1.5, 26x1.5, 26x1.90, 26x1.95, 26x2.0, 26x2.1, 26x2.2.

So, if anyone here knows what would be the closest match I would be happy to know.
I have not had much luck with any of the preset settings (on my cateye computers) always using custom. Here is how I recommend to measure the circumference:


Inflate your tire to desired psi
Put a mark of chalk on the garage floor and bike tire
Sit on my bike and roll forward one revolution until the bike tire mark comes back to the floor
Mark the end position on the ground
Measure the distance between the marks on the ground, convert to mm (for the Cateye) and set the custom tire circumference.


I have found differences between different tires (both 700 x 25) and even differences with the same tire (air pressure difference).