Polar S710 Reviews, Specs and Shopping. I've had this heart rate monitor for a while now, so here's a long term review. I also have a very low end Polar and a big Suuanto.
The reality is that most of the time I just end up using the dumb old unencoded Polar because it has been so reliable.
I got the S-720i plus the power output system. So nearly 600 clams worth of gear to replace the Campagnolo cyclocomputer and a basic Polar. What I found was that the power output installation was super tricky although there are quite a few websites that go through it.
Also after one year, one of the three sensors went bad, the chain speed sensor. I haven't had time to get this sent back to Polar and fixed, so I just took it off. As a plain speed, heart rate and cadence, the main problem is that the wireless sensors have been incredibly unreliable. There is no light or anything that tells you if the wireless stuff is even on and it wasn't clear what to do. The wired power output thing was much more reliable until it broke.
As a training system the heart rate zones and things are great, but the system is very complicated to use on the road since it has so many modes. Ultimately, although expensive, I'd recommend the Campagnolo native system ($200!) if you have Campy just because the buttons for controlling it are in the Ergolevers themselves. Super convenient. If you have to get a system, get a wired one, not wireless, the wireless ones seem pretty flaky to me.
But here's the undocumented solution that I'll have to try, but basically, I now suspect the batteries are dead in the wireless system since it has been two years now and probably the power output is too low. It is also unclear what happens when you go with a buddy with a wireless system. I'm guessing you get lots of interference.
bq. For those of you losing the signal regularly, there is a fix. the transmitters, either speed or cadence have 3 output settings adjustable inside the case. they come from polar set at the lowest output so they do not interfere with another riders monitor. if you open the case of the transmitter you will see a dip switch as i remember. just change the setting and give it a try, you'll not see an indication of what setting does what but trial and error will solve your problem. just make sure that the oring is seated properly when you close the case.