Does Polar Fix Inaccurate Power Meters?

[JTE83]

I know Polar fixes broken Power Meters, because I broke my cord and speed sensor and Polar fixed them Both times. The cord was fixed under warranty. and the speed sensor replaced for $25.

The problem is I bought a Power Output Kit from ebay (no warranty) and I just finished installing and calibrating it. The power readings were too high! My first run and the results are

HR avg 132 Speed avg 12.9 mph Power avg 214 watts
Max Speed 22.0 mph Max Power 390

This is on a 51cm Cervelo Soloist Team with HED 3 wheels!
My parameters:
chain weight 248.3 g
chain length 1324
span length 399

Has anybody ever sent in to Polar an working power meter that was fixed for inaccuracy? What did Polar replace and how much was charged?

I have 4 Polar Power kits (3 from ebay).

 

[wilmar13]

I had mine give some really high readings for a while, don't know what happened, because it was fine, then gave high readings for about two weeks, then went back to normal again. It went high by an even factor of 3 and was consistant, so I assume it was some bug in the computer rather than sensor.

But why do you think your numbers are too high? 390 watt max doesn't seem high at all.

 

[Tom Anhalt]

I know Polar fixes broken Power Meters, because I broke my cord and speed sensor and Polar fixed them Both times. The cord was fixed under warranty. and the speed sensor replaced for $25.

The problem is I bought a Power Output Kit from ebay (no warranty) and I just finished installing and calibrating it. The power readings were too high! My first run and the results are

HR avg 132 Speed avg 12.9 mph Power avg 214 watts
Max Speed 22.0 mph Max Power 390

This is on a 51cm Cervelo Soloist Team with HED 3 wheels!
My parameters:
chain weight 248.3 g
chain length 1324
span length 399

Has anybody ever sent in to Polar an working power meter that was fixed for inaccuracy? What did Polar replace and how much was charged?

I have 4 Polar Power kits (3 from ebay).

I'll echo the question...why do you think the power values are too high? Without any additional info, those look pretty reasonable to me.

As an aside, occasionally my Polar will give obviously wrong readings (way high). I've discovered that merely popping out the battery from the handlebar mount will temporarily "fix" the problem and is a typical symptom (on my unit anyway) of the battery needing to be changed. It's probably a circuit problem brought on by low voltage.

 

[JTE83]

I'll echo the question...why do you think the power values are too high? Without any additional info, those look pretty reasonable to me.

As an aside, occasionally my Polar will give obviously wrong readings (way high). I've discovered that merely popping out the battery from the handlebar mount will temporarily "fix" the problem and is a typical symptom (on my unit anyway) of the battery needing to be changed. It's probably a circuit problem brought on by low voltage.

I have a Kestrel Talon and a TCR Aero 2 with good well calibrated power meters. On the Kestrel Talon I did 217 W avg and got an avg speed of 19.8 mph. So those Initial Cervelo reading are high. I'll pop out the battery to see if that works, otherwise I'll look for my spare batteries and try them.

I'm gonna put Flightdeck on the Cervelo soon. This and a power kit is an awesome combination!

 

[Tom Anhalt]

I have a Kestrel Talon and a TCR Aero 2 with good well calibrated power meters. On the Kestrel Talon I did 217 W avg and got an avg speed of 19.8 mph. So those Initial Cervelo reading are high. I'll pop out the battery to see if that works, otherwise I'll look for my spare batteries and try them.

I'm gonna put Flightdeck on the Cervelo soon. This and a power kit is an awesome combination!

Without more info about the courses you were riding these bikes on, it's really not possible to judge which seems reasonable or not.

Here's an idea for how you can get a better check on your PMs accuracy. Find yourself a nice, steady, relatively steep (6-8% average grade) climb that takes ~10 - 20 minutes to do (even a ~5 minute climb would be OK too). Weigh yourself and the bike (total rig weight) and then climb it at a steady pace (not "all-out"). Then, using your time, calculate your average speed and see what the "power given speed" calculator at www.analyticcycling.com predicts. That should give you an idea if it's reading high or not.

Oh yeah...one more idea. Are you taking the average power numbers from the watch or after downloading to the Polar software? I've found that the average power displayed in the watch on my S710 has absolutely no basis in reality (I think its a bug). However, upon downloading to the Polar software or cyclingpeaks, the average is correct. Also, the average power in the Polar software is by default set to not include times of zero power...this tends to inflate the average power reading. You can change that to include the zeros.

Hope this helps.

Tom

 

[JTE83]

My Kestrel data was for a workout on Chicago's Lake Shore Drive Bike path. This is a flat route. I'll use my Cervelo on my next workout there. Hopefully it will be accurate. My last time using the Cervelo the reading were half good and bad.

 

[Bloggy]

I'll echo the question...why do you think the power values are too high? Without any additional info, those look pretty reasonable to me.

As an aside, occasionally my Polar will give obviously wrong readings (way high). I've discovered that merely popping out the battery from the handlebar mount will temporarily "fix" the problem and is a typical symptom (on my unit anyway) of the battery needing to be changed. It's probably a circuit problem brought on by low voltage.

Just a note on that. Once the Voltage drops on the Battery as it dies the 2.8V across the Cadence sensor could in theory drop in and out of the measurable range. This could create variations on your cadence readings and therefore change the perceived power reading. This is only my theory as I'm not sure what the mathematical realtionship is between the power and the cadence, but there is certainly a relationship as the power will not show up without the cadence measurement present.

 

[JTE83]

OK - I guess I know what the problem is ... Polar kits are inaccurate for avg power / avg speed readings when biking in the city in stop and go situations. So my readings where high avg power per low avg speed for both my Kestrel Talon and Cervelo. The avg power / avg speed comparison is only good for a nonstop bike path workout.

I finally had a good workout and good data from my workouts on Chicago's LSD. Both my Cervelo and Kestrel have comparable results:

Kestrel: 163 W avg / 17.6 mph avg / 85.4 % MHR
Cervelo: 167 W avg / 18.4 mph avg / 83.24% MHR

 

[Tom Anhalt]

OK - I guess I know what the problem is ... Polar kits are inaccurate for avg power / avg speed readings when biking in the city in stop and go situations. So my readings where high avg power per low avg speed for both my Kestrel Talon and Cervelo. The avg power / avg speed comparison is only good for a nonstop bike path workout.

I'm a bit confused...why do you say this? Is this something to do with misunderstanding the auto start/stop feature? Does it have to do with how the Polar reports average power without zeros? Also, as I previously said, the average power reported when looking at a file on my S710 (on the watch itself) is rarely, if ever, the correct average. I HAVE to download into either the Polar software of Cyclingpeaks to get the right number. No big deal...I never look at the numbers on the watch anyway.

 

[jmocallaghan]

JTE, your numbers look fine. Really. The power avg may be a touch high base on the lack of zeros averaged but that's about it.

I know Polar fixes broken Power Meters, because I broke my cord and speed sensor and Polar fixed them Both times. The cord was fixed under warranty. and the speed sensor replaced for $25.

The problem is I bought a Power Output Kit from ebay (no warranty) and I just finished installing and calibrating it. The power readings were too high! My first run and the results are

HR avg 132 Speed avg 12.9 mph Power avg 214 watts
Max Speed 22.0 mph Max Power 390

This is on a 51cm Cervelo Soloist Team with HED 3 wheels!
My parameters:
chain weight 248.3 g
chain length 1324
span length 399

Has anybody ever sent in to Polar an working power meter that was fixed for inaccuracy? What did Polar replace and how much was charged?

I have 4 Polar Power kits (3 from ebay).

 

[MY02_STi]

......Also, the average power in the Polar software is by default set to not include times of zero power...this tends to inflate the average power reading. You can change that to include the zeros

Tom,

Could you point me in the right direction to do this with the PPP software ? Darned if I can find the 'option'

 

[Tom Anhalt]

Tom,

Could you point me in the right direction to do this with the PPP software ? Darned if I can find the 'option'

Sure...I was recently unaware of this as well, but it was pointed out to me that you can find it for anything you have selected by:

"If you go to 'View' --> 'Selection Info...' you can view both NZAP and AP w/ zero's included in the Polar software."

I was still using an older version of PPP4 and when I did this there was only NZAP (non-zero average power) shown. So, I went to the www.polar.fi website download section and got the latest update. Now it can see it

Hope that helps.

 

[MY02_STi]

Hope that helps.

Thanks