is PP the angle position so important in every ride?

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kdx200
Posts: 173
Joined: Sat Jan 14, 2017 10:09 am

is PP the angle position so important in every ride?

Post by kdx200 »

Hi,
ive configured the PP and checked with you and its working fine. (i think)
Last ride i start riding and as always the first numbers are weird but in this case were TOO weird (i ve never read above 800w or so) but i didnt pay attention to much.
About the minute 10 i saw better numbers but STILL TO HIGH for the same street and zone that i know very well. So, pushed the PP and tightned very well (the numbers went to 0 and about another 8 minute to restart), the position was not the "correct" as aloways. it was about some milimiters near the "lock".
Then the numbers were ok and was a happy training.

So the question is... if the first 8 minute are the "setup" /" calibration"... why the numbers were so high when the calibration ended? was this "not perfect" lock the issue? is a little difference (like the one happend to me) enough to show "distorted" numbers (they were about 50% higher) after the calibration minutes?. Must the PP be at the SAME (i mean the exact position) in every ride? does the "first 8 minute" envolve this "positon" issues?

thank you very much!
ale
Velocomp
Velocomp CEO
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Joined: Fri Jan 11, 2008 8:43 am

Re: is PP the angle position so important in every ride?

Post by Velocomp »

Among other things, PP measures slope, with incredibly fine tolerances (less than a 0.1% change in slope makes a measurable difference in watts).

So, yes, the angle at which the PP is angled on the bike is incredibly important.

You'll note that PP instructions say that, prior to each ride, you should attach PP loosely to its mount, then push gently on it from above and behind, so that it rotates "up" and bumps GENTLY into the mount stop. With PP in this "limit" position, you then tighten the mount screw completely.

By following this procedure you'll "angle" the PP into the exact same position prior to every ride, and you will get solid watts readings from the first second of your rides.

If this procedure is not followed it's OK, but it takes PP the first 8 minutes of the ride to figure out that its mounting angle has been changed, and to correct its internal settings.

So, if the mounting angle has changed, then during the first 8 minute period, where PP is readjusting things, watts readings can be wrong by a little or a lot, depending how far "off" the current mounting angle is, compared to where it was mounted during the prior ride.

I note from your post that you were able to rotate the PP during your ride, by pushing on it. PP MUST BE RIGIDLY ATTACHED; IF YOU CAN ROTATE IT THEN IT IS NOT TIGHTLY ENOUGH ATTACHED TO ITS MOUNT.
John Hamann
kdx200
Posts: 173
Joined: Sat Jan 14, 2017 10:09 am

Re: is PP the angle position so important in every ride?

Post by kdx200 »

John you are very clear and i was aware of this,

my point is this: in a simple way, the pp can be in 2 positions (i mean to "very front-locked at front/forward" A or to "very back-locked at back" B). This 2 positions has obvioosuly different angles, minimun but a lot for a PP sensor.

So, if the 8 minute do the calibrating, the watts must be the same in the A or the B position (the angle is different).

In my case the readings (after the 8 minute calibrating in both A and B position) were higher in the A position. Sorry if iam not clear, my PP is working ok but like to know this details... iam working to be an ambassador!

thnbk you very much
alejandro
Velocomp
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Re: is PP the angle position so important in every ride?

Post by Velocomp »

Ahh...now I see your point (I think!).

Positions A and B are different by about 10 degrees---a huge amount for the slope sensor, but also a significant amount for the wind port.

The wind port catches different amounts of air in the two positions. This will cause differences in watts when the two mounting positions are compared.

Decide which way you're going to mount the device, then use the out-and-back procedure to best calibrate the device.
John Hamann
stewartclark2002
Posts: 13
Joined: Thu Dec 01, 2016 6:35 pm

Re: is PP the angle position so important in every ride?

Post by stewartclark2002 »

I've been following this thread on angle position with interest and trying to ensure my Powerpod is mounted in the same position each ride. However with the PP being so sensitive to change in angle should we also take account of where we switch PP on - for example switch it on at the same point on my driveway rather than at different places that may be at different relative ground angles.
Velocomp
Velocomp CEO
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Re: is PP the angle position so important in every ride?

Post by Velocomp »

It makes no difference "where" you switch on PowerPod.

PP memorizes its angle relative to the bike frame. As long as you don't change the angle of the PP relative to the bike frame you're OK. This is why we ask users to GENTLY rotate their PP "skyward" in the mount, until it hits the stop position. Then, tighten the screw so that the PP cannot rotate. Following this procedure assures that the mounting angle of the PP is the same to the bike frame.

When the relative of the PP to the bike frame changes (for example, by rotating the PP in its mount so that it points "lower" towards the ground), then it will take PP about 8 minutes to figure out its new relative angle to the bike frame.
John Hamann
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