PolishPostal

Wondering if anyone else has experienced this problem.

I have a Polar S520 w/ wireless speed & cadence sensors. My 1st bike was a Trek 1000. The Polar worked great. In the past month I have upgraded to a Trek 5200. Now I can't seem to get the 520 to pick up the cadence sensor signal when mounted on the bars of the 5200. The distance is roughly the same for both setups. I'm wondering if the carbon fiber is absorbing the signal. I've been pulling my hair out trying to solve the problem so any help would be greatly appreciated.

Thanks!

Markedoc

I have the same problem - on my Ti Litespeed. I actually have the speed sensor on the back wheel, and my speed sensor works and the cadence has gone from working sometimes to working never.

I did just replace the battery in my watch - the original battery didn't last all that long and I am guessing it was old to begin with. The watch now picks up HR much faster - haven't tried my other bick which has the cadence sensor - will have to try it (I am riding indoors now).

Dutchy

Does the sensor show a flashing light when the magnet comes past? It should flash for the first 30seconds. The sensor and the magnet have to be REALLY close, less than 2 mm. Mine has been working flawlessly for 2 years on a carbon bike. Otherwise, it might be the batteries?

CHEERS.

Mark

PolishPostal

The light is flashing. If I remove watch from the handlebar mount and move it toward the sensor it will begin to pick-up the signal. Maybe I'll try changing batteries and see if that helps.

Thanks.

Cable43

bump!
I have the same problem
It seems to be a distance thing.
if i move the watch closer to the sensor as I pedal it pics up fine, but if I go all the way up to the handlebars with it, it doesn't pick up. I don't get it i've been messing with this for weeks now!!!!!

any help

could it be the size of my frame?
60" frame with 100mm stem????
wtf!!!

paulrad9

You need to increase the transmission signal in the sensor. From Polar's site:

Loss of speed or cadence readings

If you observe either the speed or cadence readings drop out while riding, and the sensors and receiver have been mounted as per the factory instructions, the problem could be caused by obsorbtion of the sensor output signal by the bike frame. If the sensor has been in use previously with no problems, it could be an indication of a low battery voltage.

It is always recommended to send any Polar unit which is malfunctioning back to an authorised Polar repair centre for checking.
However, by following the below proceedure, the problem may be overcome. If you don't have the correct small philips head screwdriver or are not confident, don't attempt the adjustment and return to an authorised Polar repair centre.

Please first try and position the sensor as close as possible to 90 degrees to the wheel to get the best transmission lobe to the receiver. If this does not help, the sensor range can be increased as follows:

To increase the transmission range on the S510/S520/S710/S710i/S720 s-series speed/cadence sensors only:

Remove sensor from the bike.
Undo 2 small screws holding the two halves of the sensor together with a small philips screwdriver.
Carefully remove one section of the housing (end with cable ties).
Carefully slide the exposed printed circuit board a little way out.
Remove the jumper plug from the inner most pin and insert it over the two pins closest to the edge of the circuit board. This will give the maximum range. Shorting out the inner two pins with the jumper plug gives the medium range.
Re-assemble carefully in the reverse order.
Becareful not to over-tighten the two screws which can either distort or crack the case leaving the unit not water resistant.
Further information can be found on Page G82 of the S510 user's manual or Page G90 of the S710i/S720i user's manual.
TO ENSURE SENSOR WATER RESISTANCE IS MAINTAINED, PLEASE BECAREFUL DURING RE-ASSEMBLY THAT THE FINE RUBBER SEALING RING AND CASING ARE NOT DAMAGED.

After reassembly, if the sealing ring or casing appear to be damaged, please immediately return to a Polar service centre to be replaced before re-fitting to the bike.

Note. Increasing the transmission range may interfere with other bike riders with the similar Polar setup and will also shorten the battery life of the speed/cadence sensor.

Markedoc

Remove the jumper plug from the inner most pin and insert it over the two pins closest to the edge of the circuit board. This will give the maximum range. Shorting out the inner two pins with the jumper plug gives the medium range.

I've done this, and put a new battery in as well. Still doesn't work for me. Speed sensor has always worked fine. Cadence is/was a waste of money (for me). I don't use the Polar anymore now that I have a Powertap ... time to eBay it.

mossi

Just had a talk today to a Polar rep. Surprisingly he new what i am talking about. He said the problem with CARBOM frame is known due to the way carbon works (see the Black Bird of he US Air Force). He recommend to try to mount the sensor as perpendicular as possible to the magnet.
For me after increasing the signal range, with my Six/13, i succeeded to have it working when was mounted on the upper bar of the rear side of the frame. But i must admit that the signal is not as stable as it was with a none carbon frame.

spgny

I have a 5200...have had speed sensor for a few years..vitually flawless....bought a Polar S-series cadence sensor last year from a non-bike specific seller, looked like seller sold everything..it worked for a day..then basically never worked or was sporadic. I changed the battery, still nothing. I called Polar and they said repostion. Did that every possible way, nothing. I thought I got ripped off on e-Bay.

I want to get another but am fearful of dealing with that pain in the a$$ again if it as an issue besides seller...let us know what happens...

luv2climb

One thing that I found was to make sure the watch was on the same side of the bars as the cadence sensor was. This means the left side of the bars in most cases.

In addition be sure to mount the sensor on the top of the downtube. I have seen some people mount it under the downtube for cosmetic reasons and this moves it further away.

Doing both of these things keep the frame from interefering as much as possible.

I am riding a full carbon Look.

kleng

Hi

I'm using a 625x with a cadence sensor and speed sensor on a carbon frame with no problems at all with
signal dropouts, My cadence sensor is mounted on the rear half of the seat tube (non drive) side pointing backwards, the 625x watch is mounted on the opposite side of the bars (so its even further away from the sensor). Haven't had to do the signal strength modification, so it might have something to do with the sensitivity of the 625x. My set up shouldn't work given the problems everyone else has, but it does. As you can see from the photo, I've even got a CF bottle cage in the way.

Can I ask what the Polar receiver units being use by those having problems with the cadence signal ?

Cable43

it was my water bottle cage........................ I tried EVERYTHING, then switched to a carbon cage and that di the trick.. been great for a while!

thanks all for the advice

mossi

Now i have a new problem. The speed sensor signal is not holding. I finally put it on the front wheel, but now for home training i lack it. Any experience where to put it for the back wheel?

Cable43

not personaly.. but give it a try.. can't hurt to try