The Garmin Edge uses GPS + a barometric altimeter to determine altitude so it is supposedly a lot more accurate than the Forerunner that just uses GPS. The Forerunner is very often *way* off. For example, I climbed a hill this morning that is marked as a 12% grade. The forerunner told me it was -- get this -- a 427% grade! Somehow I got up to 14,000 some feet in less than a mile...

Now that was a particularly egregious error but I do find that it regularly gives me readings of 18+% on a hill that I know to be 8% at its worst.

That said, it is a steep hill! The good thing about grades that steep is that it is difficult to make them *too* steep. (They never do seem so steep in the photos though, do they?)

Solobiker, I think I need to ride with you! I seem to run into steep grades anytime I head west!

Anne