Originally Posted by SpongeDad
Excellent point. I can say that when the pressure changes enough to change my "apparent" altitude at my start point by several hundred feet, the relative changes stay constant. Thus it would appears that the system is linear within say a 1000 foot range.
That's good news. I could care less what my highest altitude is - I just want to know the difference in altitude. Not that it isn't nice to have both accurate, but one is definitely more important than the other.
Okay, related question for those with altimeters (or GPS units for comparison sake): On different rides, how much variation are you finding for the DIFFERENCE in altitudes? For example, if you climb 500 feet, does it sometimes read as low as 475 and as high as 525 or what?