I posted a thread earlier about the new polar power meter to get some opinions on it. The good, the bad, and the ugly. From what Ive read, Polar was trying to fix up the problems that they had on the first generation. Well, people were testing them out months ago and I want some real feedback. Does it work? Is it accurate? Is it worth it?
As I always start these posts…I WORK FOR POLAR
I originally mounted my battery pack under the chain stay, Polar says seat stay. Had it mounted directly under the Power Sensor and feel too much was going on with magnets, sensors, batteries. Now I have mine mounted towards the rear der, not directly under the Power Sensor. I will eventually mount it on the seat stay. Why did I mounted there?? I wanted to see if it would work so I could answer athlete questions. I found I have to make sure the contacts(plugs) and snug. Working well. Had it cut out once in awhile. I am making sure the AAA batteries are snug in the sleeve. Software is real good. You can set a wattage target sone instead of a HR target zone
Been using it since around April. If you saw the write up in pezcyling - that was my bike they used for the photo shoot.
Anyhow - to attempt to answer your questions, with the caveat that power training is new to me - so I don’t have a lot of reference points.
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Setup on the bike - let the LBS do it. Many bits, can get a bit tricky to get the sensors set up properly if you have curved chain stays and seat stays. Take the time to get an accurate chain length and chain weight. This makes a huge difference to the calculations. Took a bit of tweaking to get everything aligned properly, however I have had to make no adjustments since.
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There is wiring, albeit minimal. a plug from the battery to the chain sensor and a wire from the chain sensor to the rear derailleur. Make sure you allow flex in the latter since the derailleur moves around. I have had no issues so far with anything even coming close to snapping, so I gather this is a big imporvement over the old design. These are big wires/plugs, and do not look anywehre near as fragile as the old design.
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Accuracy - well, I really don’t know, since I don’t have a way to do a lot of control tests. What I can say is it is consistent. Riding certain training routes I get a pretty good idea of how I am doing and good comparisons week to week. From riding with friends with powertaps - the numbers seem to be in the right ballpark, but as I said - no actual controlled measurments. So far have had no weather issues, so dust, dirt, rain don’t seem to bother it.
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Great software, very easily manipulated. Good ability to cusotmize displays while you ride - you have about 5 or 6 different screens you can configure, so you can flip from a power based on to a speed based one on the fly. about 4 elements per display. Trianing rides I have speed, power, elapsed time and cadence, but you can have elevation, slope, avg speed , L/R balance, whatever you want. IR interface to your computer - if your machine doesn’t have a built in IR interface, you can buy a USB 1.2 IR interface for about 15 bucks. DO NOT buy the polar interface that some of the other HR monitors use - that is proprietary and will not work with the 400/600 series. The standard cheap interface is what you want. So far the original AAA battery is still working, so it doesn’t seem to blow out batteries. No problem integrating rides into CycleWorks/Training Peaks - works just fine.
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Is it worth it - well, I put my old Fuji Roubaix up on a swap meet at my LBS, so I applied the sales credit of that to this, plus they give a tri club discouny, so the whole thing cost me 30$. Works for me. Seriously, they come in around 6-7 hundred for the full rig, so about half a powertap new. I think you are probably getting at least half that performance. If you buy just the sensors for another bike (so another 3 hundred or so), you can have multiple bikes configured in one computer, so there is a multi bike capability that doesn’t mean swapping wheels or whatever. THat is kinda nice if you ride two bikes.
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Downsides - any time you change a chain you will need to re-gather your data - so if you even go from compact to large gearing you would need to do that, or if your chain is wearing and you need replacement. Probably not as accurate as some higher priced units, so I really guess how important that few percentage variance is to your training.
I am a pretty mediocre cyclist. This has helped me manage my power output on the rides (less blowing myself out on hills, more event application for longer etc). Also, I have upped my cadence from an average of 76 to an average of 92 since using it. The cycling efficiency calculations and the L/R balance can be pretty revealing in training yourself to an even pedal stroke. I probably use the cadence and efficiency more than the actual power output during my rides, and expamine the power data later. So far to date my average speed is up 3 mph - but I was starting from pretty far down the cycling food chain.
This is one man’s opinion, and as I said, I am new to power so I cannot say better/worse than other systems. It works for me for now.
- Setup on the bike - let the LBS do it.
Please don’t take this the wrong way, but I find that statement kind of humorous. As you state, the results you get from a Polar system are highly dependent on the care that’s taken in the installation. So much so, that when people have asked me “Should I get a Polar or a PowerTap?”, my first question to them is “Will you have the bike shop install it?” If they say “Yes”, then I say “Get the PowerTap.”
Installing the Polar isn’t “rocket surgery”, but it does requires getting a few details right, and then making sure they stay “right” in the future.
- Accuracy - well, I really don’t know, since I don’t have a way to do a lot of control tests. What I can say is it is consistent. Riding certain training routes I get a pretty good idea of how I am doing and good comparisons week to week. From riding with friends with powertaps - the numbers seem to be in the right ballpark, but as I said - no actual controlled measurments. So far have had no weather issues, so dust, dirt, rain don’t seem to bother it.
I can help you with that, here’s what a months worth of rides with both a Polar and a PT look like from a ride average power standpoint:
Not bad, huh? BTW, that ~10W offset is due to drivetrain losses…and it changes with chain age!
- Downsides - any time you change a chain you will need to re-gather your data - so if you even go from compact to large gearing you would need to do that, or if your chain is wearing and you need replacement. Probably not as accurate as some higher priced units, so I really guess how important that few percentage variance is to your training.
That’s not true. When you change a chain, the only critical thing is to physically weigh the new chain. For example, over the past 3 years, a stock DA 9 speed chain has slowly gotten lighter and lighter with, presumably, manufacturing changes. Changing gearing doesn’t affect anything. The chainspan length (i.e. the chainstay length entry) doesn’t change.
Since the unit uses the chain length and weight to calculate a “chain density” for the tension calculation, it’s OK to just consistently use the numbers for a 116 link chain (or whatever the “stock” length of the chain you use) instead of the actual length as installed on the bike. What I typically do before installing a new chain is to place the chain in it’s packaging on the scale to get the 116 link weight plus the packaging. I then install the chain and weigh the packaging and subtract that from the 116 link chain weight. That number gets entered into the unit and I don’t need to change the chain length of chainstay numbers. Make sense?
Hope that helps.
I knew just about nothing about power meters when I bought the Polar power meter. Set it up myself and used it with little trouble.
BUT it really is like a toy, I took it all off and sent it back to Performance Bike for a refund. Bought a PowerTap off of Ebay and haven’t looked back. Much better and easy to use.
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I knew just about nothing about power meters when I bought the Polar power meter. Set it up myself and used it with little trouble.
BUT it really is like a toy, I took it all off and sent it back to Performance Bike for a refund. Bought a PowerTap off of Ebay and haven’t looked back. Much better and easy to use.
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That’s a highly debatable opinion.
I see that you can program the computer for two bikes, do you have to put in two different chain lengths and weights or do the numbers come off one entry?
BTW, thanks for your help, your post was exactly the type of stuff I was looking for. I am just geting into power training and I can get the Polar WIND Power Meter for a pretty good price, but I just wanted to make sure that I wasnt throwing my money away.
I see that you can program the computer for two bikes, do you have to put in two different chain lengths and weights or do the numbers come off one entry?
BTW, thanks for your help, your post was exactly the type of stuff I was looking for. I am just geting into power training and I can get the Polar WIND Power Meter for a pretty good price, but I just wanted to make sure that I wasnt throwing my money away.
Just to be clear (since I’m not sure if I was initially), all of my experience has been with the older Polar PM model. From what I understand, however, the new WIND version basically operates the same (from a power calculation standpoint), with the notable exceptions of wireless transmission to the head unit and 1 sec recording intervals.
With the S710/S720 style computers, the 2 bike setups stored in the watch have their own settings for chain weight, chain length, and chainstay length. I had 2 separate power modules mounted on 2 different bikes and easily swapped the watch back and forth. It’s just a couple of button pushes to switch from one bike to the other. I’m assuming the CS600 is set up the same.
Could you post a comparison of durations shorter than an entire ride? Maybe something like 5x5 min intervals on varying terrain and gearing?
I see that you can program the computer for two bikes, do you have to put in two different chain lengths and weights or do the numbers come off one entry?
BTW, thanks for your help, your post was exactly the type of stuff I was looking for. I am just geting into power training and I can get the Polar WIND Power Meter for a pretty good price, but I just wanted to make sure that I wasnt throwing my money away.
Oh yeah, here’s a nice writeup on installing the older Polar power unit. The installation tips should also apply to the new units:
http://users.ox.ac.uk/...nstallation%201.html
IMO, it’s a very good write-up, but I did have just a few small comments and suggestions. Here they are:
Nice write-up Xav! I’ve been thinking about needing to put up something similar myself…since it seems like I’m always answering the same questions about the setup. I have just a couple of quick observations I’d like to add:
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A dirty chain really doesn’t pick up very much dirt…In fact, I reweighed my old chain the last time I swapped and it was still within 1 gram of the “new” weight.
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You might want to relocate the wheel speed sensor “fin” so that it’s pointing down from the chainstay rather than up. With it pointing up, if it is knocked into the spokes somehow, the spokes will “grab” it and tend to wreak havoc on the sensor and the wire…ask me how I know this With it pointed down, the spokes will tend to knock it away if it is accidentally moved into interference.
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I like your magnetic “prefit” method…But, to be honest, the power module doesn’t necessarily NEED to be parallel to the chain span. It’s less likely to rub at the tail end if it is, but it’s not a requirement.
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The “middle” mark actually does serve a purpose (for me at least). It marks the “middle” of the ~1-1.5" square area where the inductive sensor resides inside the module. The chain should pass over that area at all times.
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I agree that the rubbing in some small-small gear combos is a non-issue. The key measurement is that the chain should never be further than 25-30mm away from the top of the module (measured at the “middle” mark…see, you DO use it, just not how Polar thinks Wink ) when in the usable gear combo that takes the chain the furthest from the sensor.
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You might want to show a little more detail about how the cable is “dressed” near the rear dérailleur to prevent the wire from being sucked into the jockey wheels and severed. This is one of the most common difficulties with the unit, and is a main reason why this sensor is now attached to the power module with a removable connector on the new “wireless” units.
Overall, it’s a great writeup…and I’ll definitely be directing people to it in the future! Thanks.
Hope that helps too!
Could you post a comparison of durations shorter than an entire ride? Maybe something like 5x5 min intervals on varying terrain and gearing?
Even better, how about an overlay of the 2 plots for a crit? 
Thanks to gregclimbs, here is an animated gif of the screengrabs in the following order:
The first is the polar file (red power, green cadence)
The second is the PT file (yellow power, blue cadence)
The third is pt on top of polar
The fourth is polar on top of pt
http://wattagetraining.com/mothballs.gif
Here’s some discussion from the wattage google group of the files from 3 crits I did that day, but you may need to join the group to read it:
http://groups.google.com/...m=7#a91859a53e9dc346
Taken from that above discussion:
Here are the peaks for the WKO+ default durations for the day:
5s 10s 20s 30s 1min 2min 5min
Polar 879 861 782 652 456 379 309
PT 966 908 794 614 434 348 293
FWIW, the only types of efforts that are reported dramatically differently are very short, sprint type efforts. In this case, the Polar tends to “clip” the peaks of the effort due to it’s averaging/saving method…especially what gets saved because of the “downsampling” algorithm that’s used. Also, as discussed in the linked thread above, the “downsampling” affects the NP calculation for HIGHLY variable efforts, but it’s typically not an issue otherwise. Most everything else, including 5 minute intervals (i.e. VO2Max workouts) are VERY close for both AP and NP.
Hope that helps.
Can anyone tell me if the old chest straps work with the new watch? Or if the new chest strap works with any of the old watches - like the 625?
thanks
DB
BUT it really is like a toy, I took it all off and sent it back to Performance Bike for a refund. Bought a PowerTap off of Ebay and haven’t looked back. Much better and easy to use.
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I bought a powertap but it just really is like a toy
I sold the pos on ebay and got a srm and look much better then the losers I ride with
dirt
this is not a true story
wvarta,
Do you have a pic showing the battery pack under the chain stay. I asked my LBS to install the power sensor follwing your instructions but the didn’t know how to do it or couln’t do it. ALternatively, could you post more detaled instructions on how to place the battery pack under the chain stay. I ride a P3C if that helps.
Thanks in advance.
Hector
I am handicapped at posting photos. I will email you them. I found that with the Power Sensor on top of the chain and the battery pack mounted underneath need to be offset. Meaning, mount the battery pack under, but position it or slide it back towards the rear der. Essentially, looking at the bike from left to right or rear der to botom bracket imagine battery pack underneath, nothing above it, then as the pack is ending the power sesnor is now mounted. Bottom, dont have one above the other
Thanks, I replied to your message with my email address.