- Nov 3, 2003
Pelotonium said:It actually happens quite often on long rides. I ride on a F1 track with relatively no altitude change ( < 15m ), and yet I often see a gradual creep corresponding to 150m or more during a 3hr ride.
I know 150m isn't much, but barometric pressure is not a great way to measure altitude.
Thinking more about this, either:
1) Your altimeter isn't temperature-compensated and the temperature is changing during your relatively 'static' rides, or
2) You always ride during major frontal passages (your numbers equate to a 0.5" Hg change in three hours; the weather would be impressive), or lastly
3) Your altimeter is faulty, needs a new battery, etc.
I say #1 or #3.