Did you get it figured out??? I was so curious to see if it really matters, so I Google'd... here's a link that might help ya...

http://www.cyclingforums.com/archive.../t-229529.html

I love riding so much more now that I can see all sorts of stats... it really motivates me to ride harder and longer! I've hit 40 mph going downhill out in the country (over the speed limit!)! That was a gas!!!!

enjoy!!!