Polar power?

ryan16 said:

I currently have the polar s725 with cadence and I was wondering about the power meeter for this. How accurate is this? Is this something I nreally need to get?

Thanks for all advice

There was a test done comparing the SRM, Powertap, and Polar. You can probably find it through Google. Based on the results, it looks like the Polar was reasonably accurate, but did have some erratic readings. I don't have one, but based on what other people have said, the drawback to the Polar unit is that it's supposed to be a [censored] to set up. It is the least expensive, however.

I have been using the Polar power meter for a few months now. first, the company claims that one battery will last 400 hours. it is more like 150-200. second, it does give weird readings, but it isnt that bad. for no reason (i.e. power lines, cell towers etc.) i will get "00" for a second or two about every 10-20 mintues. might be more, but i AM trying to watch the road!

accuracy is relative. but the unit gives a good "balpark" figure. i take the data with a grain of salt. if it says 180 watts, i will assume 175-185 watts. but this isnt bad because power fluctuates wildely, even at a steady state. so when reading the data ON THE BIKE, Polar is fine. But when analysing data after a ride on your PC, then that is a different story. this is where accuracy is an issue. if i averaged 226 watts on a ride, did i REALLY average 226 or 245? i dont know. so, if you are using a power meter simply to monitor while on the bike, polar works well. but if you are more interested in post-ride analysis, polar is not too wonderful (go with power tap for this one). if you want the whole anchelada, go with power tap. BTW, installation is not that bad.

Thanks guys I really appreciate your advice and expertise. I'll do some research and see what I decide to do later.

kennf said:

There was a test done comparing the SRM, Powertap, and Polar.

biketechreview.compm review.htmOpen ↗

vio765 said:

accuracy is relative. but the unit gives a good "balpark" figure. i take the data with a grain of salt. if it says 180 watts, i will assume 175-185 watts. but this isnt bad because power fluctuates wildely, even at a steady state.

All the PMs are sufficiently accurate for training purposes. We're talking about a few percentage points. Hell, I couldn't maintain my power within a few percentage points (other than steady grade climbs) if my life depended on it. Consistency is another matter, but I hear that the Polar is sufficiently consistent if set up correctly.

vio765 said:

accuracy is relative. but the unit gives a good "balpark" figure. i take the data with a grain of salt. if it says 180 watts, i will assume 175-185 watts. but this isnt bad because power fluctuates wildely, even at a steady state. so when reading the data ON THE BIKE, Polar is fine. But when analysing data after a ride on your PC, then that is a different story. this is where accuracy is an issue. if i averaged 226 watts on a ride, did i REALLY average 226 or 245? i dont know. so, if you are using a power meter simply to monitor while on the bike, polar works well. but if you are more interested in post-ride analysis, polar is not too wonderful (go with power tap for this one). if you want the whole anchelada, go with power tap. BTW, installation is not that bad.

The accuracy of the meter is questionable on accelerations. But as for workouts, I think the polar kit is accurate! On July 5th, I did a 7 mile lap ride with no winds, and my power output kit results were 19.8 mph avg at 217 W avg with no drafting and biking in the drops. Predicted results from the http://www.kreuzotter.de/english/espeed.htm website showed that I should have done 19.6 mph avg! This at 84F 81% humidity and my riding weight. So that's accurate!

Training with power is great because you train at power levels not speed which varies with the wind conditions.

What did you eventually decide,I have been considering the polar but after reading threads decided against it for now, seems like to much hassle🙂.

ryan16 said:

Thanks guys I really appreciate your advice and expertise. I'll do some research and see what I decide to do later.

The Power sensor battery will be drained if any sensor is active during transport. This could be the wheel, crank or chain moving. If you unplug the cable to the mounting unit, the battery will last longer BUT it is another thing to remember. And disconnecting it will introduce dirt to the electrical connections.

Ryan, I've owned the unit almost half a year, but can't recommend it.

Its accuracy varies depending the chain position. This may be less of an issue if you only ride say a 53x15 combo as you're time trialling. But if you're climbing hills, you may be surprised that despite grinding up a steep hill in your 39x25, the polar unit tells you you're only doing 70W (if only it were so, groans your body!). So you can fix this by repositioning it, but find you get dropouts on the opposite scale ie 53x12 etc. Or that in transport a small movement makes a big difference. Don't get me wrong - I have had some consistent readings, but then enough problems to want to dump the unit.

This accuracy issue is the big thing. In my view, I don't have confidence in it, so no matter how cheap it is relative to the others, its wasted money, in my view. BTW, I spent ages following the video online from polar on the setup and reading their book. Its a big hassle.

Further problems are that it only records at 5sec intervals, therefore will never capture your sprints (which is important if you are training this) or jumps.

I intend to buy a power tap when funds allow. Am slightly concerned its uncoded heartrate strap will mean the unit picks up other riders, but I'm interested in the watts.

The other PT advantage is you can use multiple bikes - in the UK its common to use a winter bike and a racing bike. You would have to completely dismantle the polar.

So it all boils down to accuracy. Others above have advised the accuracy difference is not so great. As I said, its completely inaccurate over short distances ie sprints, and is very sensitive to its position on the chainstay when measuring longer efforts (remember too, this is a flat block, mounted normally on a curved seatstay, therefore prone to move, no matter how tight you pull the zipties).

Another problem is that its not convenient to mount/dismount the receiver from the bike. This is because you've already had to spend time threading it through your gear/brake cables, ensuring the contact points touch, then tying it really tight (or you'll get dropouts). Then after your ride, you have to reverse the process. I imagine the PT unit just slides off. This is important if you will do this twice almost every day ie mount/dismount.

Shame, Polar made great heartrate monitors. Oh, and customer service? - sucks. I'm still waiting to hear from them since about 4 months ago.

Would love to hear from polar users who love the unit? 🙂

i have polar power units installed on 2 bikes. i'm happy with the product and it is not as hard to set up as people think. my first installation took a bit of time to complete, but for the second bike, it was a breeze. polar has an instructional video on their website that really helps.

as far as accuracy goes, i do see some fluctuation between my two bikes (a specialized roubaix pro & cannondale team saeco), but it is accurate enough for the type of riding i do.

i have often thought about upgrading someday to a Powertap or an SRM, but then i figure "why spend all that money"? i went the polar route because it was an incremental investment for me since i already had the HRM & used their training software.

i would recommend it wholeheartedly.

I wouldn't recommend the Polar power unit either. I never could get it setup to read correctly, especially at high cadence.

Time is money, and for the amount of time you have to screw around with it, you are better off with a PT or SRM.

Torgos said:

I wouldn't recommend the Polar power unit either. I never could get it setup to read correctly, especially at high cadence.

Time is money, and for the amount of time you have to screw around with it, you are better off with a PT or SRM.

The PT has no coded HR Transmitter and it only has 1 workout file. The Polar is coded and it has 99? workout file capability or so.

The only thing difficult about the Polar installation is installing the sensor to proper height and installing a good cadence magnet. The cadence magnet that comes with the kit stinks. You have to glue a magnet to your pedal for cadence.

JTE83 said:

The PT has no coded HR Transmitter and it only has 1 workout file. The Polar is coded and it has 99? workout file capability or so.

The only thing difficult about the Polar installation is installing the sensor to proper height and installing a good cadence magnet. The cadence magnet that comes with the kit stinks. You have to glue a magnet to your pedal for cadence.

I broke my last heart rate transmitter so I've used both my PowerTap and SRM without a transmitter and for every thirty minutes of racing (crits and track so I am very close to the other riders) I typically get about two seconds of heart rate data that could only have come from another person's heart rate strap(and I'm recording either at 0.5 second intervals or 1.26 intervals which is ten and about four times faster than Polar's best rate). Coded is a great marketing point for Polar and since they are the only folks AFAIK that sell those straps with a non user serviceable strap, a great income stream for them as well.

That's the reason I'm not getting a PT right now - it's not coded. I think the late 2006 PT SL model will come out coded and with multiple workout file capability. So I'll be waiting. I like the PT's 1.26 sec recording rate. The SRM is best but it's too expensive for me.

I got the Polar sensor but still havent got the S725. Installing the sensor was easy enough for me. For the cadence magnet i bought a round magnet that fits right on the hole of my pedal axle. Will see how it works once i got the HRM unit maybe next week.

I have installed a polar power meter and have to say, if you're serious about power, this unit is rubbish! As was stated earlier in this thread, the readings are all over the place when using different gears; particularly at the high and low end. The unit goes haywire whenever you go near high voltage power lines; especially if you ride along side a rail line. If your cadence sensor moves slightly it gives false readings; if the power sensor moves a few mm from being knocked etc, it affects the readings, when you get out of the saddle up a hill the readings are ridiculously high and the list goes on and on.

Considering the accuracy is affected if any of the 3 sensors move slightly, or if your chain is a bit old, how can you ever be sure if your power output is improving, unless of course you cover your usual course in a faster time with the same or lower HR or perceived exertion... wow, what I hear you say, go back to the trusty old Cateye Astrale and listen to what my body is actually telling me... nahhh!

Sarcasm aside, even when the unit gives reasonably consistent readings, what really annoys me is that when on the small chainring and going relatively easy, the chain is forever slapping on the sensor. When you are on the small chainring the clearance between the chain and sensor is as small as 5mm; therefore, at the exact point of your pedalling deadspot where there is little tension on the chain, the magnet pulls the chain down till it hits the sensor.

I guess the bottom line is "the bottom line"... you get what you pay for. There is probably a very good reason why SRM cranks cost 3k+

Cheers
Chris

The polar gets more inaccurate when you go to the 23, 25, or 27 tooth cogs. And it sucked when I lost my power readings during my last race because the sensor got knocked to the side.

But the Polar is cheap. Got a used one of ebay for $240. Polar now makes all dealers sell it for $350 - what a ripoff.