Elevation drift

[KimG]

Has anyone else noticed that the iBike elevation setting drifts? I set it on Friday but come Monday it a about 200 feet higher. The roads I ride are a bit bumpy and broken but if shocks from broken road surfaces are causing this I think that there may be a design problem. Other than that everything else appears to be normal.

[Velocomp]

Elevation drift is caused by changing barometric pressure, which is caused by changing weather. This is completely normal for all barometric pressure measurement systems.

[KimG]

I don't mind having to check/set the elevation before each ride but I don't recall that being addressed in the Newton+ documentation. This brings to mind another; question doesn't the elevation play a roll in the watts calculations?

Thanks for the quick reply.
Kimball

[Velocomp]

I don't mind having to check/set the elevation before each ride but I don't recall that being addressed in the Newton+ documentation. This brings to mind another; question doesn't the elevation play a roll in the watts calculations?

Thanks for the quick reply.
Kimball

No, elevation is not involved with watts calculations.

[Zoltan]

I see that apart from any barometric driven elevation drift, there is a drift of appr. 1/3600 feet per sec (actually I estimate it 1/3592). I have a very small sample I checked just one ride file before concluding it. Is it just for some doublechecking purpose? Or is it the result of some elevation tweak by the user?

Sorry I am a newbie with Isaac and for the time being I am just setting up theories.