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Polar power sensor - Is it worth it?(9 posts)

Polar power sensor - Is it worth it?PODIUMBOUNDdotCA
Aug 1, 2002 6:17 PM
I have had the Polar S710 for 3 months now and absolutely love it. But now I'm to the point where I'm trying to decide whether or not to buy the power sensor for it. There has been a lot of hype over why power is so much better than HR and since my hrm records the information this plotted with cadence and speed as well as heart rate could be interesting. But is the information it can provide worth it???

Thanks,
Nick
PodiumBound.ca
re: Polar power sensor - Is it worth it?I Love Shimano
Aug 1, 2002 10:26 PM
Hey Nick,

It would be better to use a power sensor because there is a lag in HR. For example, you may be at 140 HR, but your effort is already at max (i.e sprinting). A power sensor will be more accurate in displaying what kind of offert you are actually putting out.

Try checking out the Ciclosport HAC4 or Alti. They are cyclocomputers that display wattage and % grade too. Not bad for the price.
Do they actually work?filtersweep
Aug 2, 2002 4:16 AM
I wonder how well the Polar power sensor actually works, since it allegedly detects chain tension, which is certainly less intrusive to a bike than a rear hub mod.
HAC4 or Alti.Iwannapodiumgirl
Aug 2, 2002 5:06 AM
Do you know how the power is measured on these Ciclosports? I looked at the UK version of the website (my German is a little rusty!), and it does not say how it is measured. Further, there appears to be no additional sensor!
CalculationsMike Prince
Aug 2, 2002 5:41 AM
It is done through a calculation involving your speed, gradient changes, wind resistance and combined rider/bike weight (input during initial setup). I have an Alti and while I would not claim that the numbers are dead-on accurate, it seems to be a pretty entertaining and useful feature.

In other words, what it does makes sense - no 500-watt outputs while coasting downhill at 45mph, etc. I think the manual says the power numbers are +/- 20W on climbs and +/- 40W on the flat.
What do the pros use? nmHRH
Aug 2, 2002 7:11 AM
Big Picture - Is it Worth It?grzy
Aug 2, 2002 10:53 AM
That is a good question. I too run the S710 and have had one since soon after they were available. Frankly the power sensor feature is a bit of a turnoff to me. It's a mess of wires and sensors all over the bike and it's something like another $350. Then what exactly are you going to do with all of the data. How exactly are you going to use it? Do you really need it or is just geeky self obsessiveness gone bad? Do you need something approaching $1000 worth of instrumentation plus a PC to tell you that you're slow or fast up a hill? How does this add to your ride experience and enjoyment or does it take something away as in damn, I only put out 387.49 watts on that hill today, yesterday it was 389.24 watts - no desert for me!
I guess it depends on your goalsPODIUMBOUNDdotCA
Aug 2, 2002 12:38 PM
It depends on a lot of things. If your a recreational cyclist just trying to stay fit a hrm is great. Altitude and stuff is just a bonus. Where stuff like power/computer uploadability really become important is as you begin racing and either 1) have a coach who can interpret all the info or 2) you can do it yourself. The better your program is the more you can maximize your genetic gifts and therefore go from there and power is a step in the right direction. Then of course once you climb up the ranks and become a provincial or national contender it becomes even more important as it can catapult you into the upper levels of the sport but not many people are this fortunate.

Cheers,
Nick
PodiumBound.ca
Might beSoultrain
Aug 2, 2002 11:01 PM
The MFG spec on accuracy is something like +/- 10%
That is pretty far off. By your own admission you are a powerful sprinter so I would imagine you would be in the 1200-1800 watt range, give or take. So 150 watts one way or the other at max effort. The system, by nature is incredibly
hard to calibrate. I would imagine that the readings would vary as said above with climbing being less accurate, perhaps as high deviation as 15-20%.
This is the main dilema, The Polar will be in the ball park,
but you don't know if it's reading high or low.
It should, however read consistantly. IE the differences in wattage would be quite accurate from day to day, as seen on a training log or datasheet.
So you may be working with slightly wrong numbers, but gains or losses would be fairly accurate.

Dan