Polar CS600 Power - First on the Block...

[Tom Anhalt]

The road was very smooth. I have this problem since spring. It appeared from one day to the next and stayed until now. I mounted the PM on two different bikes, used 9 and 10 speed chains, changed the position of the chain speed sensor becouse I thought the chain speed on the small ring is higher.... nothing helped.
(Big chain ring measurements are still OK)

The problem with polar is that I have bought the PM used by ebay.
So I have no warranty and believe that the polar service is very expensive.

I have a second defect Polar PM here. I used it for 3 years before the electronics died. If I would know if the chain speed sensor or some cables are defect I would replace them (electronics engineer) but with the running big chain ring it makes no sense

IME, Polar service (at least here in the states) is very reasonable. I had a power module serviced just last year (with moisture sensitivity, i.e. VERY large power readings when roads were damp, and a severed chainspeed sensor) and it was repaired for less than $30. Give it a shot. In fact, why not send in both?

 

[Andre.T]

IME, Polar service (at least here in the states) is very reasonable. I had a power module serviced just last year (with moisture sensitivity, i.e. VERY large power readings when roads were damp, and a severed chainspeed sensor) and it was repaired for less than $30. Give it a shot. In fact, why not send in both?

I sent an email to the German Polar Service. Many thanks for your support Tom.

 

[JohnMcP]

... changed the position of the chain speed sensor becouse I thought the chain speed on the small ring is higher.... nothing helped.
(Big chain ring measurements are still OK)

This is interesting. Is there an optimum position for the chainspeed sensor? On the Polar installation video (on the Polar USA website) the mechanic swings it 'forward' so that in the big ring x big cog combo (not that we use this combo ) the chain just clears the sensor as it passes. This means that the angle between the chain and the face of the sensor varies with gear selection. In low gears, with the derailleur pulley well forward, the sensor and chain make angle of around 25 degrees.

Is this right? Or should the sensor be rotated on its axle far enough back to remain parrallel to the chain at all times? Or does it make no difference.

I'm not an electronic engineer!

McP

 

[Andre.T]

This is interesting. Is there an optimum position for the chainspeed sensor? On the Polar installation video (on the Polar USA website) the mechanic swings it 'forward' so that in the big ring x big cog combo (not that we use this combo ) the chain just clears the sensor as it passes. This means that the angle between the chain and the face of the sensor varies with gear selection. In low gears, with the derailleur pulley well forward, the sensor and chain make angle of around 25 degrees.

Is this right? Or should the sensor be rotated on its axle far enough back to remain parrallel to the chain at all times? Or does it make no difference.

I'm not an electronic engineer!

McP

I don´t know where is the optimum position for the speed sensor but I made the experience that closer to the chain is better.
I made a "long hole" in the speed sensor and positioned it with a gap of 1mm to the chain.

Your hint with the speed sensor position was very good but I still positioned the sensor "back" as much as possible (Shimano Derailleur). So the sensor should have the same distance to the chain in all gears. I will double check it at the weekend.
Maybe I also lift up the PM by 3-4cm to test if the big chain ring is still working.
If not the problem is located to the PM itself.
No respond from Polar so far...
Regards
Andre

 

[Tom Anhalt]

I don´t know where is the optimum position for the speed sensor but I made the experience that closer to the chain is better.
I made a "long hole" in the speed sensor and positioned it with a gap of 1mm to the chain.

Your hint with the speed sensor position was very good but I still positioned the sensor "back" as much as possible (Shimano Derailleur). So the sensor should have the same distance to the chain in all gears. I will double check it at the weekend.
Maybe I also lift up the PM by 3-4cm to test if the big chain ring is still working.
If not the problem is located to the PM itself.
No respond from Polar so far...
Regards
Andre

Andre,
How far away is the top of the sensor module from the chain in your largest USEABLE big chainring - large cog combination? To get reliable readings in all useable gears, it should never be further than 25-30mm from the top of the sensor case, measured at the "middle" mark on the case.

If you're already following that recommendation, you wouldn't be able to raise it 3 to 4 cm.

Another thought, how new is the battery in the watch handlebar mount? I can usually tell when my battery is getting low when I start getting flakey power readings. I don't think the circuitry likes lower than spec voltages. On that note, you may want to check the solder joints inside the connector to the watch holder. With moisture exposure they can tend to corrode and will prevent the full voltage from reaching the power sensor.

 

[Andre.T]

Andre,
How far away is the top of the sensor module from the chain in your largest USEABLE big chainring - large cog combination? To get reliable readings in all useable gears, it should never be further than 25-30mm from the top of the sensor case, measured at the "middle" mark on the case.

If you're already following that recommendation, you wouldn't be able to raise it 3 to 4 cm.

At the moment the sensor is directly mounted onto the chain stay.
I know the problematic when the gap between sensor and chain becomes to big.
In the past I lifted it up by 1cm. However, my Powertap says it worked fine with this distance . On the small chain ring I have a distance of 2,5cm (values are only estimations, I will measure it on weekend) and it doesn´t work.
I will lift the sensor up that I have the same distance to the chain on the big ring as now on the small. 3-4cm was only a estimation, likely it is less.

Another thought, how new is the battery in the watch handlebar mount? I can usually tell when my battery is getting low when I start getting flakey power readings. I don't think the circuitry likes lower than spec voltages. On that note, you may want to check the solder joints inside the connector to the watch holder. With moisture exposure they can tend to corrode and will prevent the full voltage from reaching the power sensor.

I will also check it on weekend and let you know.
Many thanks
Andre

 

[Tom Anhalt]

At the moment the sensor is directly mounted onto the chain stay.
I know the problematic when the gap between sensor and chain becomes to big.
In the past I lifted it up by 1cm. However, my Powertap says it worked fine with this distance . On the small chain ring I have a distance of 2,5cm (values are only estimations, I will measure it on weekend) and it doesn´t work.
I will lift the sensor up that I have the same distance to the chain on the big ring as now on the small. 3-4cm was only a estimation, likely it is less.

I will also check it on weekend and let you know.
Many thanks
Andre

Great. Just to be thorough...have you physically weighed your chain? Also, how accurate is your chainstay measurement? I'm just checking all the things that could affect the readings on a properly performing unit.

It'll be interesting to see how it performs after you raise it up to the proper spacing.

 

[Andre.T]

Great. Just to be thorough...have you physically weighed your chain?

No, I calculated the weight and then changed the value for "calibration".
When the PM was working I made some hill TT and then compared the Polar values to the calculated values (www.Kreuzotter.de).
After changing the chain weight I got tolerances <5%. I don´t know the chain weight at the moment. I think about 280g which could fit to the 10 speed chain I actually use.

Also, how accurate is your chainstay measurement? I'm just checking all the things that could affect the readings on a properly performing unit.

It'll be interesting to see how it performs after you raise it up to the proper spacing.

The chain stay length is 420mm, the middle marking should fit +/- 5mm.
I can make some photos on the weekend.

 

[Tom Anhalt]

No, I calculated the weight and then changed the value for "calibration".
When the PM was working I made some hill TT and then compared the Polar values to the calculated values (www.Kreuzotter.de).
After changing the chain weight I got tolerances <5%. I don´t know the chain weight at the moment. I think about 280g which could fit to the 10 speed chain I actually use.

I HIGHLY recommend that you actually weigh it. It's a lot easier and more accurate than they way you went about "calibrating" it.

The chain stay length is 420mm, the middle marking should fit +/- 5mm.
I can make some photos on the weekend.

Don't worry about if the "middle" mark is exactly in the middle of the chainstay. That's really a minor issue in the installation; it doesn't have to be centered in the least. In my experience, the location of the sensor on the chainstay along the center axis of the bike is driven more by the location of the magnet on the crankarm and having that line up with cadence trigger.

Did you happen to get a chance to raise it up yet and try it out? Just curious.

 

[Andre.T]

I HIGHLY recommend that you actually weigh it. It's a lot easier and more accurate than they way you went about "calibrating" it.

Hm, I had good results with my methode but I will check it with the PowerTap if I get Polar working again.

Don't worry about if the "middle" mark is exactly in the middle of the chainstay. That's really a minor issue in the installation; it doesn't have to be centered in the least. In my experience, the location of the sensor on the chainstay along the center axis of the bike is driven more by the location of the magnet on the crankarm and having that line up with cadence trigger.

Did you happen to get a chance to raise it up yet and try it out? Just curious.

I raised it up but when I wanted to start riding I recognised that I forgot my watch in the flat where I live during the week .
I will test it next weekend.

The polar service answered my email on friday. They suggested to place the sensor on the chain stay that if the cain is on the middle of the cassette the cain runs over the middle of the sensor.(top view.) As you can see in the attached pictures it should be OK in my installation. I will call them tomorrow what it costs if I send them the unit for repair.

 

[Tom Anhalt]

Hm, I had good results with my methode but I will check it with the PowerTap if I get Polar working again.
I raised it up but when I wanted to start riding I recognised that I forgot my watch in the flat where I live during the week .
I will test it next weekend.

The polar service answered my email on friday. They suggested to place the sensor on the chain stay that if the cain is on the middle of the cassette the cain runs over the middle of the sensor.(top view.) As you can see in the attached pictures it should be OK in my installation. I will call them tomorrow what it costs if I send them the unit for repair.

It's hard to tell from the pictures, but is the pic with the measurement with your chain on the largest usable cog with the large front chainring? If so, I would move it up at least 5mm closer. If it's on a smaller cog, I'd DEFINITELY move it up higher.

Also, from looking at the top view, I think I would also move it back along the chainstay a bit. The important thing about the chain passing over the top of the sensor is that it always passes over an ~4cm square box centered on the "middle" mark of the case. That's where the inductive sensor is inside the module. Where you have it now, it appears that when you have the chain on the large chainring and are in the small rear cogs, the chain may not be passing over the top of the case. That's going to reduce the signal strength.

Lastly...If you listen to one thing I tell you, it's weigh the chain. Believe me, you'll be glad you did. Oh yeah...and weigh it every time you replace it, too. The weights change over time, even for the same part number chain from the same manufacturer. It's enough to make a difference.

 

[Andre.T]

It's hard to tell from the pictures, but is the pic with the measurement with your chain on the largest usable cog with the large front chainring? If so, I would move it up at least 5mm closer. If it's on a smaller cog, I'd DEFINITELY move it up higher.

Also, from looking at the top view, I think I would also move it back along the chainstay a bit. The important thing about the chain passing over the top of the sensor is that it always passes over an ~4cm square box centered on the "middle" mark of the case. That's where the inductive sensor is inside the module. Where you have it now, it appears that when you have the chain on the large chainring and are in the small rear cogs, the chain may not be passing over the top of the case. That's going to reduce the signal strength.

Lastly...If you listen to one thing I tell you, it's weigh the chain. Believe me, you'll be glad you did. Oh yeah...and weigh it every time you replace it, too. The weights change over time, even for the same part number chain from the same manufacturer. It's enough to make a difference.

Hi Tom,
I promise to weigh it next weekend
I believe that that all adjustments have an impact to the accuracy of the power measurement, but the accuracy is not my problem at the moment.
On the small chain ring I miss 50% of power, very fluctuating values, the complete measurement isn´t working.
I use polar powermeter since 3 years, often played around with chain wight, sensor positions..... sometimes it was inaccurate but it everytimes worked.
I will go ahead with the test next weekend and if I get no new results I have to send it to Polar for maintenance.
Best regards
Andre

P.S. If you put your mouse on the pictures you will see the gear ratio.

 

[Tom Anhalt]

Hi Tom,
I promise to weigh it next weekend
I believe that that all adjustments have an impact to the accuracy of the power measurement, but the accuracy is not my problem at the moment.
On the small chain ring I miss 50% of power, very fluctuating values, the complete measurement isn´t working.
I use polar powermeter since 3 years, often played around with chain wight, sensor positions..... sometimes it was inaccurate but it everytimes worked.
I will go ahead with the test next weekend and if I get no new results I have to send it to Polar for maintenance.
Best regards
Andre

P.S. If you put your mouse on the pictures you will see the gear ratio.

Aaah...I see. The measurement is in you 53x16? Yes...you DEFINITELY need to raise it up, even if it means that it rubs on the case in the 42x12 (which you shouldn't be using anyway). Also, if the potential of rubbing concerns you, try to keep the PM as parallel to the chain as possible by raising both the front and the rear. It doesn't make it work any better, it just makes it less likely for the tail end of the module to rub on the chain.

Also, one other thing to check when you get "odd" readings like that is the battery and the connections. In my experience the PM can act odd when the voltage to the electronics gets low. Make sure the battery in the watch mount is fresh and also take apart the connector on the harness (it unscrews in 2 places) and take a look at the solder joints. Corrosion on the solder joints can cause insufficient voltage to the electronics. If they're corroded, find a fine tip soldering iron and touch them up.

Keep us posted,
Tom

 

[Andre.T]

Aaah...I see. The measurement is in you 53x16? Yes...you DEFINITELY need to raise it up, even if it means that it rubs on the case in the 42x12 (which you shouldn't be using anyway). Also, if the potential of rubbing concerns you, try to keep the PM as parallel to the chain as possible by raising both the front and the rear. It doesn't make it work any better, it just makes it less likely for the tail end of the module to rub on the chain.

Also, one other thing to check when you get "odd" readings like that is the battery and the connections. In my experience the PM can act odd when the voltage to the electronics gets low. Make sure the battery in the watch mount is fresh and also take apart the connector on the harness (it unscrews in 2 places) and take a look at the solder joints. Corrosion on the solder joints can cause insufficient voltage to the electronics. If they're corroded, find a fine tip soldering iron and touch them up.

Keep us posted,
Tom

I opened the connector last weekend also and measured the voltage.
It was 2,95V at the connector. I forgot to measure the battery voltage to check the contact resistance.
I will replace the battery on weekend also. The contacts I have already resoldered.
The reason why I don´t realy believe that this is the root of the problem is the running big chain measurements.
More results on weekend.....

 

[Andre.T]

Last week, after a phone call with the German Polar Service, I sent the pictures and failure desciption posted here also to Polar.
They also suggested to mount the chain sensor more to the back that it doesn´t conflict with the "front derailer".
They wanted to send me some rubber-spacer for it.
At the weekend I raised the unit up again (with my spacers) and mounted it more to the rear wheel.
(Photos attached)
After this modification, changing the battery and after measuring the chain weigh of cause I tested the unit again.
After the modification the unit was not working on both chain rings.
I will send the unit to Polar for investigation now.

Also the second Polar PM. On this unit the cadence LED is blinking but the values are not displayed by the watch.
Speed is displayed, therefore it can not be a problem of the data line I guess.
I will keep you informed...

 

[SteveO2]

Well.... good luck to all of you struggling to get the PM to work reliably. After 2 failed warranty Power Modules, I finally convinced the dealer to give me my money back for the CS600+Power. I was also pretty ticked off that Polar customer support always made it sound like it was my fault that the PM didn't work, and that they wouldn't admit to a problem either. So, I've purchased a competitor's power product instead, and while it costs a bit more, it works right out of the box with no install hassles or drop-outs. Good luck to all of you who stick with the Polar and I hope you eventually get it to work.

Regards;
SteveO

 

[baffer]

well , after getting my unit back from polar, I installed it once again according to the descriptions... and guess what, it works perfectly now... I have done 7 hours of cycling with no drop-outs and solid data....

When polar sent it back, they replaced the original magnet with a much stronger (and thicker) version. Also I broke the battery-holder during the last install, and they replaced the yellow battery-holder with a slightly different (more sturdy) version (orange color).

After all I think my problem was a combination of a crappy cadance magnet, and the faulty battery holder, with bad (weak) springs...

I will keep you guys posted

 

[vetboy]

well , after getting my unit back from polar, I installed it once again according to the descriptions... and guess what, it works perfectly now... I have done 7 hours of cycling with no drop-outs and solid data....

When polar sent it back, they replaced the original magnet with a much stronger (and thicker) version. Also I broke the battery-holder during the last install, and they replaced the yellow battery-holder with a slightly different (more sturdy) version (orange color).

After all I think my problem was a combination of a crappy cadance magnet, and the faulty battery holder, with bad (weak) springs...

I will keep you guys posted

I'm curious about that new battery holder. Is it an big improvement over the original? I find mine (then yellow one) very difficult to get into the can and it is possible to push it in in such a way that it does not allow the contacts to connect at the bottom. Mine may have to be "broken" (accidentally of course ) if the new one is much better.

Joe

 

[baffer]

I'm curious about that new battery holder. Is it an big improvement over the original? I find mine (then yellow one) very difficult to get into the can and it is possible to push it in in such a way that it does not allow the contacts to connect at the bottom. Mine may have to be "broken" (accidentally of course ) if the new one is much better.

Joe

cant really say that the new one is very different, however this one did not break after pushing it in with some force

 

[vetboy]

cant really say that the new one is very different, however this one did not break after pushing it in with some force

Thanks

Joe