Rollers and momentum

[Eden]

I went on a group ride a few weeks ago and everyone in the lead pack had a GPS computer whereas the cyclists who took a half hour longer to do the 2 mile climb didn't have such computers.

Correlation does not imply causation.....

One could easily look at this from the other side too ... all the riders who are faster are using GPS computers, whereas the slower cyclists don't feel the need to have them.... The slower cyclists could be more casual riders who don't buy fancy toys, they could have less $$$ to spend and therefore not only do not have GPS, but have much heavier equipment, etc. There could be many reasons you see this relationship that have nothing to do with GPS computers making people faster.