Polar s720i / s725 and power kit feedback?

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Tippster
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by Tippster

I'm thinking of getting either a Polar s720i ($210 is cheapest I've seen) or Polar s725 (cheapest I've seen is $275) and a power kit (cheapest I've seen is $315).

Is anyone using any of these?

any feedback?

what level of detail does the power kit provide?



thanks,

Tippster
"Ride it like you've just stolen it!"

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Arjan
Posts: 36
Joined: Thu Jun 24, 2004 1:21 pm
Location: Amsterdam

by Arjan

I've been using a s710 with the power output set for almost 2 months now.
It does help me with training.
The pedaling index and power index functions help me with improving my technique.
I don't know how precise the the power readings are but i think they are fairly accurate.
One thing i don't like is that the sensor is easily damaged by the chain and i had problems with my foot touching the sensor, knocking it out of position.
But overall i'm happy with it, it sure draws the attention of other cyclists. :D

by Weenie


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Tippster
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by Tippster

Would the power sensor still work if protected by a lizard skin chainstay guard?

will the watch display multiple readings?

i.e.
current speed
average speed
current HR
current cadence
current power output

all at the same time?

if not, is the diplay customisable? how many different units can you display at once? 720 or 725?
"Ride it like you've just stolen it!"

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Arjan
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by Arjan

i'm not sure if a lizard skin would help, my problem is that my feet point outwards. But now that i have new cleats the problem is as good as gone.
I know 2 other people with the power kit, i've never heard them about their feet hitting the sensor so this may not be a problem for you.
As for the display, it shows 3 readings at a time.
Like this: Pedaling index
Power output
Heartrate
You can of course change these readings, this is how my s710i model works but a s720 or s725 works the same.
Hope this will help.

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ras11
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Location: SC, USA

by ras11

I've had mine a couple years now.

Overall it's ok. It's a cheap power meter, so you get what you pay for. There are a lot of wires, and many parts are cheap plastic. I guess that keeps the grams low, but it doesn'tt inspire me.

The computer functions are good. There are other software options on the internet which I found to be better (http://www.cyclingpeakssoftware.com)

The accuracy is better then I expected, similar to the power tap. Peak power is difficult to acquire due to slow acquisition time.

Best feature is the Cadence, HR, Power screen. And cost is reasonable (as for as power meters go) Although they are all over priced if you ask me.

Worst feature is the array of sensors one needs to setup, if one gets out of whack it'll stop working. The cadence and power are built into one part which is a pain to adjust vertically and laterially.

Would I buy it again, maybe. I think I'd be tempted to test out the Power Tap pro coming out this winter, which is supposed to be totally wireless and better for peak power measurements. But I'm sure it'll be at twice the cost.

I don;t know about LizardSkins, but I wrapped my unit with 4-5 layers of electrical tape. Works good for me. The black hides the dirty chain marks.

I've had no problems with hitting the sensor with my foot. I can;t even imagine how someone could hit it... unless you had a crazy chain line, duck-toed feet, or something weird. The sensor should not go beyond the chain in the last cog, so if you're hitting the sensor, then you're likely hitting the chain with your foot also... that's very odd.

I do periodically have to play with the sensors, but it's not such a chore that I'd not use it. The data it provides for the cost is worth it.

The big thing I get from my power meter is a percieved exertion vs. actually exertion. Hard to do that w/o a power meter.

Good luck.
:-) Toys-R-Us

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Arjan
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by Arjan

I don't have weird feet :(

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HakeemT
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by HakeemT

Yes you do

Paul_nl
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by Paul_nl

ras11 wrote:
Would I buy it again, maybe. I think I'd be tempted to test out the Power Tap pro coming out this winter, which is supposed to be totally wireless and better for peak power measurements. But I'm sure it'll be at twice the cost.



Hello Ras11, do you have more info about the new power tap pro? Or where did you find the info about the 2005 power tap pro?

Paul_nl
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by Paul_nl

Paul_nl wrote:
ras11 wrote:
Would I buy it again, maybe. I think I'd be tempted to test out the Power Tap pro coming out this winter, which is supposed to be totally wireless and better for peak power measurements. But I'm sure it'll be at twice the cost.



Hello Ras11, do you have more info about the new power tap pro? Or where did you find the info about the 2005 power tap pro?


I found some information about the new Powertap SL

At velonews.com they say:
PowerTap SL
If you only want to add power measurement to a bike you already own, the vastly improved PowerTap SL could fill the bill. Weight is cut from 575 grams to 410 in the new version, courtesy of a thinner hub shell that sports enormous windows filled with carbon fiber.

The PowerTap SL has an internal torque-measuring device that measures power output 60 times per second, which it relays wirelessly to the handlebar display. The head unit records up to 150 hours of data (power, speed, heart rate, cadence and so on), all of which you're free to download to your PC. Campagnolo and Shimano freehub configurations are available.


But at topica wattage forum Jesse from powertap say it's not totally wireless.
http://lists.topica.com/lists/wattage/r ... tart=25422
But the new hub is very beautifull!!

Image

The PowerTap is wireless in the sense that it is now. From the hub to
same seat stay mounted receiver although the receiver will need to be
mounted closer to the hub (and the receiver is different internally) as
the signal from the hub is a bit weaker because of it going through the
carbon.

Additional memory will be available when we work through existing
inventory, not sure when that will be....

SL available in 24, 28, 32 holes.

$1199.99 for Hub
$1299.99 for Mavic Open Pro Wheel (we are discontinueing our prebuild
wheels other than the Open Pro 32 hole).

Jesse

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Tippster
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by Tippster

Can you get a powertap in mtb hub with disc?
"Ride it like you've just stolen it!"

Paul_nl
Posts: 462
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by Paul_nl

Tippster wrote:Can you get a powertap in mtb hub with disc?


I don't know. But I haven't seen anything about it on their website.

But you can contact cycleops at cycleops.com

Or try it at this forum:
http://lists.topica.com/lists/wattage/read

Jesse from Cycle Ops is reading that forum frequently.

by Weenie


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Weisse Luft
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Joined: Mon May 10, 2004 4:44 pm
Location: All over Texas

by Weisse Luft

With the power sensor kit and i LOVE IT! The only problem was getting it as the retailers don't stock the power kit and the 720 is sold out everywhere.

Since I had 2 weeks of waiting, I studied the installation procedures and while not practically experienced, I knew what I was doing. I got home with kit in hand at 11:05 AM. I proceeded to mount the kit and had all pieces mounted correctly by 11:29. I took it around the block for a quick test, then loaded my car up to meet my ride partner for a 6 hour drive to the mountains :)

After arriving at the mountains at 6:00 PM, I had a great supper then unloaded the bike from the car for a 2 mile test ride. Everything worked fine, maxing out at a bit over 800 Watts :). I then went to sleep for the big ride the next day.

I rode 75 miles in the mountains, starting at 5000 feet above mean sea level and doing over 5000 feet of climbs. Average power was 190 Watts (I wasn't pushing it hard for the first 20 miles) with a maximum of 600 Watts on one climb (12% for about a mile).

I have done 3 rides since that first with only one problem. The connections on the bike interface need to be clean and the strap must be rather tight, otherwise the sensors will not communicate. Other than that, the system is perfect. I have not noticed ay power output errors based on gearing but I also never run extreme combinations. I shift to my big ring when going higher than 39x14 and go to my small ring when I need something lower than 53x19 (39-53 + 12-23, 9s).

You can protect the tension/cadence sensor with anything non-magnetic and non-conductive. I trimmed a clear chainstay protector to fit. Lizard Skin(tm) is also acceptable. I also used clear tape to secure the wires to the tubes, much better protection and looks cleaner.

The only "improvement" I would recommend to Polar would be for the chain speed sensor. Using a ring of magnets to determine crank speed with a simple sensor for gear selection would be much better. You would have to program your chainring sizes but that is easy.

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