Page 1 of 1

Newton Elevation

Posted: Sun Mar 16, 2014 7:29 pm
by JulianBoulter
Hi all, my training rides all start and stop in the same place and I use the environment feature on my Newton to set the starting elevation, however I notice in Isaac when I get back and download my rides that the finishing elevation has always drifted higher and this is confirmed when I analyse route, the drift to the higher elevation can clearly be seen in the graph. Of course Isaac can correct it and wattage hardly changes but is this normal? Should I be performing a tilt calibration?

Re: Newton Elevation

Posted: Sun Mar 16, 2014 9:28 pm
by racerfern
A rising elevation indicates a falling barometer and vice versa. It depends on your locale and the time of day you tend to ride. If you switch to "set elevation" then Isaac will correct for the slight difference. Know that anytime the the elevation trend is upward, your average wattage will drop ever so slightly and again, vice versa. The barometric sensor in Newton is very sensitive and that's what the "static" elevation is based on.

Do not perform a tilt calibration, that will not help and might actually skew your results.

Re: Newton Elevation

Posted: Mon Mar 17, 2014 6:07 pm
by JulianBoulter
Thanks Fernando, so just to clarify, at the end of each ride where I start and end in the same place I should go into analyze route and enter start and end elevation as the same and hit accept correct? All other options are unchecked as I think you mentioned in this thread: http://www.ibikeforum.com/viewtopic.php ... ion#p16045

It adds about .6 watts to the power when I do this and it wont bring the blue and red lines together but basically adjusts the red line to where you entered your elevation from what I can see

Also if I analyze tilt plot it adds 2 further watts in the window but this is not reflected anywhere when i close the analyze route dialog, although it does appear to change the slope statistics. Show tilt plot appears to be showing me the analyzed slope but does not appear to be influenced by any of the check boxes

Re: Newton Elevation

Posted: Mon Mar 17, 2014 8:39 pm
by racerfern
There is no need to analyze tilt plot since the newer units are all auto correcting. As I suggested, enter your starting and ending elevation, uncheck all other boxes and move on.

Your slight variations are really meaningless numbers when you talk about .6w or 2w.

Re: Newton Elevation

Posted: Tue Mar 18, 2014 7:43 am
by JulianBoulter
Got it!

Thanks