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iBike newton's power reading error

Posted: Thu May 28, 2015 9:52 pm
by redhybrid
Hi guys,

I just got my Newton 5+ :D , I have a problem regarding the power reading on my unit :cry: . Whenever I encounter small vibrations on road while riding, the power reading on my unit drops to zero.
I have done 4 Cal ride so far and check calibration again and again but still the problem is there.

I also change the filter from dynamic to other sampling rate (0,2 sec), turn off and on Powersoke, front mount is rock solid and the cadence sensor is ok. To ensure this problem is cause by vibration I do a short ride on stone paving road.
the data
the data
06.jpg (148.84 KiB) Viewed 4219 times
Picture about shows the zero reading of power for entire ride on the stone paving road, the speed and cadence aren't. Is this indicate my unit has a hardware malfunctioning?

please help :cry: :cry:
stone paving road
stone paving road
IMAG2143a.jpg (95.18 KiB) Viewed 4219 times
front mount on my bike (solid)
front mount on my bike (solid)
IMAG2144n.jpg (67.48 KiB) Viewed 4219 times

Re: iBike newton's power reading error

Posted: Fri May 29, 2015 8:57 am
by Velocomp
The problem is your mount extension.

The mount extension you are using is not something that we make or sell. I haven't seen this one before, but my guess is that it is made out of plastic. Furthermore, my guess is that, if you push on your Newton a bit, you'll find that the mount extension flexes a little bit.

Your Newton is cantilevered out on the end of the extension. What is happening is that the flexible mount extension is vibrating on the cobbles, with the net effect that your Newton points down a little bit. This causes slope to become negative and causes watts to go to zero.

Though these kinds of extensions work just fine on "normal" roads, they can get into trouble on rough roads.

Now you know why we use machined aluminum on our front mounts, and even have a two-arm front mount--they provide the highest stiffness possible!

Re: iBike newton's power reading error

Posted: Fri May 29, 2015 9:20 am
by redhybrid
Thank you, yes you are right.

I did some experiment in my lab this afternoon and found that the deformation of the fiber reinforced plastics is quite large. Similar problem happened before in our wind tunnel experiment due to the vibration on sensors which cause error data. So I did some modification for the stand...
self made T6061 Al stand
self made T6061 Al stand
11012107_10153844677676664_1053042520962493197_n.jpg (47.39 KiB) Viewed 4206 times
old school!
old school!
11392818_10153844677721664_8031842193354024513_n.jpg (48.26 KiB) Viewed 4206 times
then I went to ride again on stone road!
Accurate data!
Accurate data!
63.jpg (143.69 KiB) Viewed 4206 times
Yes, problem solved!!! :D

Thank you very much~

Re: iBike newton's power reading error

Posted: Fri May 29, 2015 11:17 am
by Velocomp
I like your solution!