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Where to calibrate a quarq in Sydney


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#1 vince

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Posted 07 August 2013 - 05:08 PM

When I calibrate my quarq prior a ride, I am getting a reading of around -540 since last week.

 

I would like to know where I could get it re-calibrated in Sydney?

 

Thanks,

Vince



#2 lzbones

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Posted 07 August 2013 - 05:16 PM

.


Edited by lzbones, 13 February 2014 - 07:05 PM.


#3 Alex Simmons

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Posted 07 August 2013 - 06:24 PM

If you have an iPhone or iPad and a wahoo dongle to suit, you can do it yourself with the Qalvin app. Quarq have a video to show how.

http://www.quarq.com/qalvin

 

If not, then I provide a power meter slope calibration service for $40. I am located inner west Sydney.



#4 KT05

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Posted 07 August 2013 - 09:15 PM

I am new to this power thing, when i calibrate i also get negatives albeit 80's or thereabouts. I note the quarq manual says if you are inside +/- x then its ok, if not then send it in.

Why the negative value, why not a zero at calibration ? Is it a temperature issue ? Something else ?

#5 jezzaman

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Posted 07 August 2013 - 10:16 PM

If you have an iPhone or iPad and a wahoo dongle to suit, you can do it yourself with the Qalvin app. Quarq have a video to show how.
http://www.quarq.com/qalvin
 
If not, then I provide a power meter slope calibration service for $40. I am located inner west Sydney.

I just updated the firmware on my quarq from v12 to 19 using qalvin tonight. Easy. Haven't delved into all of the other functions yet but handy to know that they are available.

Edited by jezzaman, 07 August 2013 - 10:16 PM.


#6 Quack

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Posted 07 August 2013 - 10:23 PM

If you have an iPhone or iPad and a wahoo dongle to suit, you can do it yourself with the Qalvin app. Quarq have a video to show how.
http://www.quarq.com/qalvin
 
If not, then I provide a power meter slope calibration service for $40. I am located inner west Sydney.


Sounds like a good service Alex.
How would I know when to get this done for my Quarq?
And how important is it to dot he firmware upgrades? (I don't have the wahoo/qalvin setup)

#7 Alex Simmons

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Posted 07 August 2013 - 11:13 PM

I am new to this power thing, when i calibrate i also get negatives albeit 80's or thereabouts. I note the quarq manual says if you are inside +/- x then its ok, if not then send it in.

Why the negative value, why not a zero at calibration ? Is it a temperature issue ? Something else ?

 

Imagine the old style bathroom scales, with the rotating readout which spun around to show your weight when you stood on them. They had this little dial you could move either way to zero the scales before standing on them. The scales before zeroing might well have been either side of zero before re-setting it.

 

Same deal with power meter torque measurement, except the zeroing is based on a digital readout, it simply sets the value displayed at which you know to be zero torque to be the zero reference point, then when you pedal it calculates the difference in readings between that zero mark and the readings when torque is applied. It's the absolute difference between the numbers that matters, not whether they are positive or negative. e.g the difference between 20 and 100 is the same as the difference between -100 and -20.

 

What you don't want to see is large drift in the zero torque values. That's trouble.



#8 Stikman

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Posted 07 August 2013 - 11:20 PM

If you have an iPhone or iPad and a wahoo dongle to suit, you can do it yourself with the Qalvin app. Quarq have a video to show how.
http://www.quarq.com/qalvin
 
If not, then I provide a power meter slope calibration service for $40. I am located inner west Sydney.


There's now an android version too and you only need your ant stick and a cable. Works well for me but I haven't used it to calibrate yet.

#9 Alex Simmons

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Posted 07 August 2013 - 11:22 PM

Sounds like a good service Alex.
How would I know when to get this done for my Quarq?
And how important is it to dot he firmware upgrades? (I don't have the wahoo/qalvin setup)

 

I normally recommend people validate their power meter slope when they first fit the meter, after about 6 months, annually thereafter and at any time they make a major change involving the meter, e.g. changing chainrings, or if they suspect something is up with the accuracy of their data.

 

As for firmware update, hard to say but I cant imagine Quarq releasing new firmware for no good reason. Still, if the meter is working fine then should be no big deal. It might be needed however for access of the diagnostics tools.



#10 KT05

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Posted 08 August 2013 - 07:51 AM

 
Imagine the old style bathroom scales, with the rotating readout which spun around to show your weight when you stood on them. They had this little dial you could move either way to zero the scales before standing on them. The scales before zeroing might well have been either side of zero before re-setting it.
 
Same deal with power meter torque measurement, except the zeroing is based on a digital readout, it simply sets the value displayed at which you know to be zero torque to be the zero reference point, then when you pedal it calculates the difference in readings between that zero mark and the readings when torque is applied. It's the absolute difference between the numbers that matters, not whether they are positive or negative. e.g the difference between 20 and 100 is the same as the difference between -100 and -20.
 
What you don't want to see is large drift in the zero torque values. That's trouble.


Thank Alex, great explanation

#11 The Turtle

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Posted 08 August 2013 - 09:49 AM

Is calibration something that only needs to happen with crank based PM's? 

 

What about hub based ones (like mine..)?



#12 Alex Simmons

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Posted 08 August 2013 - 11:18 AM

Is calibration something that only needs to happen with crank based PM's? 

 

What about hub based ones (like mine..)?

 

Validating calibration is something all power meter users should do at some stage. I recommend a frequency in post #9.

 

One can check the slope calibration of a Powertap, however there is no facility to change it should you discover it is wrong (like you can say with an SRM or a Quarq).

 

Just so this is clear, setting the torque zero and checking/setting the power meter's calibration are two different things:

 

Setting the torque zero is something you do before every ride, and occasionally during a ride, no matter what power meter you use. All this does is validate the meter registers zero torque, when no torque is applied to the meter (no matter where in the drive train it happens to be).

 

Checking/setting the slope calibration is something you do infrequently, to validate the meter is operating accurately and using the correct slope to calculate power from the torque and rotational speed readings. Not all meters enable you to check the slope calibration (and a failure to provide this feature is a fail in my opinion). 

 

Unfortunately Garmin chose to use the word "calibration" on its head units for the function of setting the torque zero, and this can lead to some confusion.

 

Calibrating any instrument means to validate it's accuracy. Checking/setting the torque zero is a necessary but insufficient condition for checking calibration. I really wish Garmin would rename that function to "set torque zero" or "set zero offset".

 

Going back to the bathroom scales analogy, just because one sets the zero on the scales before standing on them, doesn't then automatically mean that the scales will read accurately when you stand on them.

 

I demonstrate that analogy in this blog post.



#13 trek52

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Posted 08 August 2013 - 11:18 AM

Mine sits at around 380 to 410....as long as it is consistent I think it is ok.



#14 Stikman

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Posted 08 August 2013 - 04:04 PM

Someone asked for the Android Qalvin instructions by PM so I thought I'd post them here too for everyone.  It took a little bit of research for me to get it right so I can hopefully save others the time:

 

The cable you need is a mini-USB to USB OTG.  The ANT+ stick needs to be a v2 which should be any one from the last few years at least I think.

 

You then need to get Qalvin from the app store as well as ANT USB service.You also need to install the ANT Radio Service but the current version won't work (not sure what they did with the latest update but it fails.)  You can get version 3.0 from here http://roboapk.blogs...ce-ver-300.html  I think there are instructions on how to install it on that page but if not you need to enable installation form third party sources (under security in settings) and then download the .apk file to your phone and select it to install.  Once it's on there you need to go into the Play Store application and under the menu bring up "My Apps" and then select the ANT Radio Service.  Bring up the menu and make sure that the auto update is not ticked or else it will update to a higher version and break.

 

I have no affiliation with any of the above but this all works for me on a Galaxy SIII.


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#15 Stikman

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Posted 07 January 2014 - 06:21 PM

I've just seen that there has been an update for the Android version of Qalvin which apparently fixes the problem needing the old ANT Radio Service.  I've updated the app but won't get to test it until tonight.






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