Originally Posted by
steve2k
It's got a sensor on the back wheel that measures distance - it also measures cadence with a sensor on the pedal arm - it's all very clever - except it's clearly rubbish at working out calories based on heart rate which I would have thought would be more accurate - what if I'm coasting down hill it's going to think I'm burning millions of calories.
Took a look at the manual for FR60. First of all, I was wrong, it is not a GPS, it's just a heart rate monitor / sensor receiver watch. It also says that it calculates calories based on HR if it does not detect a speed sensor.
Using HR is not a sure solution. Two different people with different fitness levels would burn different amounts of calories at the same HR. It might make more sense for the watch to assume that you're outside riding on a flat road if it receives data from a speed sensor. This way it will calculate calorie burn based on what it thinks it would cost you to push through the air at that speed.
That said, it does not seem to be doing a very good job at THAT, either, since there's no justifiable way for it to report the burn of 1100 calories/hour riding at 25 kmh. Whatever other assumptions it makes, it should be reporting something in 500..700 cal/hr range at that speed and your weight.
I would suggest to turn off the speed/cadence sensor if you want to keep getting calorie counts. I can't guarantee that numbers it reports will be any closer to reality.