HRM Spd sensor on back wheel?

[wonduhboy]

Anyone know if you can stick you Polar HRM speed sensor on your back wheel and still get reliable readings?

[Dr. Seuss]

I heard that you can take the sensor to Polar & they will make it work just fine.

[Rancher]

how much is a hrm?

[SwissVan]

5 minute job

The speed sensor (and the cadence sensor) signal can be adjusted fairly easily by the user, but as always if you fiddling with it could have warranty consequences.

 

Your user manual should have the instructions, Page G 90 for the 720i/710i

 

 

[SwissVan]

For those who cannot find / read their manual:

 

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.