Quarq Elsa Low Readings

[Hanibal]

Hello All,

My wonderful wife decided to surprise me with a Quarq Elsa power meter for my birthday.

I am quite surprised by the readings. They seem quite low to me.

They were installed by my LBS. I have only had it out for 2 rides. Each ride I have manually calibrated it to my Garmin 800 (+80)
I tested my 1 minute power by riding a local 400m hill with a 8.5 grade my average speed was 25.4 km/hr.
I currently weigh 83kg
The average power reading was 256 watts.
The whole ride was only 18km showing an average of 87 watts.

Is this too low or am I really that weak!

If I have left any info out, please let me know and I will be happy to provide.

Thanks in advance for your help.

[Strange Rover]

Does seem very low...

When you manually calibrated it did it return exactly +80 every time...or does it move around a bit...say +70 to +90 (which is what I would expect)

Did you try doing a manual calibration at end of ride to see if the number returned was still approximately the same.

What was the average speed of your 18km ride. And was this solo or in a group.

If we establish that the zero is correct then its the slope thats out...and then just need to do a simple stomp test to get rough idea on slope calibration.

I just did mine...now this is really rough...but should give some idea.

So my man cal returned -364.

Then did it again but was standing with all my weight on one pedal and holding both brakes on..the crank arm horizontal and forwards at 3 oclock.

It returned -3861

So about -3500 difference...and I weigh about 81kg.

Sam

[Strange Rover]

Ok...just did it a few more times on..was getting numbers closer to -3700 to -4000 difference between not standing on pedal and standing...did it multiple times on two different bikes and got approx same numbers (within 500 or so)

you can do it properly if you got a decent known weight...
Sam

[Hanibal]

Hi Sam,

I just re calibrated and got a +79.

I just did the test with the right pedal at 3. The result was -3416.

When the left pedal is at 9 the result is -4180. (My left is naturally stronger)

With regards to the ride itself; I was aim on doing 1 min, 5 min and 20 min test but after seeing the result of the 1 minute test I decided to head home and try and work out the problem.

Here is the strava file. The segment is called cliffbrook cres leonay

http://app.strava.com/activities/45557534" onclick="window.open(this.href);return false;

Also the ride was solo.

[Strange Rover]

Yep...pedals just like you did.

Ok...so your numbers seem about the same as mine...Im guessing the meter is working poperly. And the calibration is back to approx -80 with no weight??

So what was your average speed on that ride...the numbers still seem low to me...especially the 8.5% at 25km/h at 256w...I would guess that should be over 400w at 83kg.

Can you upload the ride to garmin connect or something.

Sam

[Strange Rover]

Analyticcycling.com says 600w for that climb.

You sure its 8.5% ??

[Hanibal]

here is the garmin file

http://connect.garmin.com/activity/287489863" onclick="window.open(this.href);return false;


Its reading + 80 as opposed to -80

[Strange Rover]

Actually, I see you loaded it to strava...I was in a rush and didnt see that....

So looking at the the data on strava its definately a zeroing issue...actually interesting that Strava calculated 627w for that climb...very close to what I got on analyticcycle.

So there are lots of zeroes in your data when you were obviously pedaling. This should be easy to fix.

On the garmin, you need to go into the settings, and go to the power meter (close to where you do the calibrate) and make sure that the "auto zero" is set to ON.

What this allows you to do is...during your ride, you back pedal 4 times (try to do it really smoothly) and the Quarq will zero itself. This is the exact same thing as stopping, getting off your bike, and going through the calibration process...its a lot easier and simpler to do. I never bother doing a calibration on mine...I just back pedal on the first down hill, and any other time I remember to care to do it (sometimes before an interval or when I dont believe the data) I have a powertap on another bike and it auto zeroes every time you freewheel...and it never gives screwy data...much easier than the Quarq.

Once you have that setting on the garmin, you can check it working by turning everything on (like your about to go for a ride) and then, with your hand, back pedal 4 times then stop and then let go of the pedal...then watch the spider carefully...it should flash an LED light to let you know it has auto zeroed itself. If it does this then you are all set. Just remember to back pedal 4 times to make it zero itself during the first bit of your ride...alot of guys like to do it after the first 5 to 15 min when the meter has been on for a while and warmed up and stabalised.

Then on your ride make sure any time you are pedalling, even very gently, you are getting some sort of power numbers. I would imagine on the ride you would have been looking at alot of zeroes...

Sam

[Hanibal]

Thanks for the info Sam but I can't seem to find an auto zero function on the Garmin 800. Are you using an 800?

[Strange Rover]

Thanks for the info Sam but I can't seem to find an auto zero function on the Garmin 800. Are you using an 800?

I see what you mean

http://www.cyclingforums.com/t/492541/q ... 0-question" onclick="window.open(this.href);return false;

One guy there says the back pedal works...try it and see if the LED flashes

Sam

[Strange Rover]

If the LED flashes when you back pedal (this is once everything is paired and ready to ride) then you should be good to go.

To gain some confidence in that the back pedal works when you are on the bike what you can do is this...

Do a manual calibration while standing on one pedal (like before)...so the cal will be something like -4000. Then go for a ride and look at the reading...it should be zero unless you are pedaling very, very hard. You actually will have to push harder on the pedal than what you did standing on it to get a reading on the screen. I think this is basically how it was working when you went for that ride...dont know how or why. Now do the back pedal thing (at least 4 times) and continue riding...you should now see some decent numbers...

...I hope

Sam

[Strange Rover]

Just googling and came across a very good post on Alex's Cycle Blog...very recently posted as well...

http://alex-cycle.blogspot.com.au/2013_ ... chive.html" onclick="window.open(this.href);return false;

Worth a read...

So the thing is with the Quarq, if doing the back pedal zero, is how smoothly and reliably you can back pedal to produce an accurate zero. I havnt tested how well this works...although hopefull later next week I should be able to cause my ant+ adapter for my Iphone should turn up and I will easily see what is happening with the zero offset as well as the torque output of the spider while Im riding along. To work out whats happening with out adapter and Iphone would be fairly involved cause, basically, when you do a back pedal zero it never tells you the new calibration value.

I didnt like doing the manual zero at the start with the Quarq cause I believed the zero needed redoing after about 5 or so minutes after things warmed up...this was based on riding around with both my powertap wheel and quarq cranks for a week or so...just about did my head in though looking at two garmins on the stem and then the post ride data they spat out.

Sam

[Hanibal]

Cheers for the info. I'm going to head back out to the hill and do a zero calibration at the base and see how I go.

I'll let you know the results.

[Hanibal]

Any suggestion on what I should be showing on my garmin when testing?

Currently I'm showing
Power
Lap power
Left% right%

Did you find a difference in the results between you power tap and quarq?