I have fitted a Polar S720i with the Power Output sensor to my Softride Solo road bike.
I also have triple chainrings fitted, and all components are standard 105 or equivalent.
I have a problem with the Power sensor. It sits on the chainstay bar underneath the chain. As the chain passes over it, it measures chain speed and vibration, somehow or other working out the Power at the pedals from that. This seems to work ok.
The problem is when I drop down to the third chainring (the smallest one, 30 teeth, I think), the chain gets very close to the Power sensor. If I drop the chain down about halfway on the rear cassette, the chain actually gets dragged onto the sensor, and gets dragged across it.
The problem is that the sensor is a very strong magnet, and this drags the metal chain down onto it. So the chain is dragged across the sensor while you are pedalling - doing all sorts of damage I have no doubt.
There is no way to make the gap any bigger, which is my problem.
Does any one else have this problem?? Can anyone suggest a solution?