Polar Install Problems

http://mywebpage.netscape.com/rechung/wattage/installation/s710photos.html

Did a little more fiddling with my power meter and I realized that even though my cadence led was turning on (green light I think). My HR was not registering any cadence signal. However, my speed was registering on the HR. So, I may not have chain speed sensor problems, I may have issues with getting my cadence sensor signal to the head unit. Anyone have a suggestion?😕

Thanks
D

tresdood said:

Did a little more fiddling with my power meter and I realized that even though my cadence led was turning on (green light I think). My HR was not registering any cadence signal. However, my speed was registering on the HR. So, I may not have chain speed sensor problems, I may have issues with getting my cadence sensor signal to the head unit. Anyone have a suggestion?😕

Thanks
D

Have you definitely switched power and cadence on in the bike setup menu? Is the s720 mounted properly on the 2 pins of the handlebar unit?

Can't suggest much else at this stage if the LEDs are all coming on.

rob of the og said:

Have you definitely switched power and cadence on in the bike setup menu? Is the s720 mounted properly on the 2 pins of the handlebar unit?

Can't suggest much else at this stage if the LEDs are all coming on.

Checked the HRM and the Cadence and Power are switched on. I am assuming the HRM is making proper contact to bike mount since I am getting a speed reading. I am wondering if I have a low battery in the computer mount or a bad wire somewhere.

D

tresdood said:

Checked the HRM and the Cadence and Power are switched on. I am assuming the HRM is making proper contact to bike mount since I am getting a speed reading. I am wondering if I have a low battery in the computer mount or a bad wire somewhere.

D

If you are not getting a cadence readout then the cadence magnet is almost certainly the problem. The one supplied by Polar kind of sucks, but one thing I found about it is that it works way better if you put it on the crank lengthwise, meaning that the rectangular magnet has its longer direction parallel with the crank. For some reason it activates the sensor better that way. It also needs to be very close to the sensor as it passes by.

Anyway, the long term fix is to buy a 3/8" cylindrical rare earth magnet from Lee Valley (online source from Canada) and stick it to the back of the pedal spindle. It is way more powerful than the Polar magnet and doesn't have to be very close to the sensor to work (mine's at least an inch away at the closest point). It doesn't even need to be stuck on with tape because it is so strong that it will stay all by itself. It's also way more attractive looking as it is nearly invisible. (The 1/2" one fits better in the crank but is so powerful that it will annoyingly pull the chain offline as it passes by the chain.) If you happen to be near Palo Alto, let me know as I have some extras.

lanierb said:

Anyway, the long term fix is to buy a 3/8" cylindrical rare earth magnet from Lee Valley (online source from Canada) and stick it to the back of the pedal spindle. It is way more powerful than the Polar magnet and doesn't have to be very close to the sensor to work .

As I've said elsewhere, if you hack the plastic apart on the magnet unit Polar provide, the magnet inside is a little tube that fits snuggly into the allen key recess in the pedal axle. It'll hold itself in place.

rob of the og said:

As I've said elsewhere, if you hack the plastic apart on the magnet unit Polar provide, the magnet inside is a little tube that fits snuggly into the allen key recess in the pedal axle. It'll hold itself in place.

It'll hold itself in place, but is fairly weak and still needs to be very near the cadence sensor for things to work. The 3/8" rare earth magnet is so powerful that it can be inches away when the crank passes by the cadence sensor and still work, thus freeing up the chain sensor placement. I've also found it much more reliable for the same reason. When using the Polar magnet, if either the magnet or the cadence sensor were to shift a small amount during the ride (from, say, hitting a bump), sometimes the shift would be enough to make the cadence sensor stop working. So far, since "installing" the rare earth magnet I've had zero failures or interruptions.

(Note that the 1/2" rare earth magnet fits the crank better but is TOO powerful as it pulls the chain offline during pedaling, which is a minor annoyance.)