polar power unit installation

If you have been reading or even care, I started a thread about power units, polar vs the others. I went with the polar unit mostly on cost and the fact that I could be the test rabbit for my shop (being we sold both SRM and the power tap to customers). So I installed it as close to instructions as possible, but there was a little problem that arose. I put the power sensor 7 mm lower than the chain (instructions say between 5mm and 10mm). The problem is, when ever I am in the small chainring in the front and the 3 or 4 smallest cogs in the rear (I use campy record 10spd) the chain rubs on the unit. Is this normal? I am just concerned that it might wear marks in the unit. I put a brand new chain on the bike so chain stretch isnt a problem and everything works perfectly (all sensors read fine), I just didn't think that the chain should touch the sensor due to the magnet pulling it there.

A quick point may be made that the bike has only been in a mechanics stand and not on the ground yet (being its -5 F here in Maine and im not going out in that).

I will be calling polar or emailing them tomorrow, depending on my repair schedule at my bike shop, but I was just curious if anyone out there had this problem and what was done about it....This is the first polar unit we installed and I want everything done properly incase there is another customer who would want one.

Thanks
Mike

 

I'm telling you it's not worth the trouble. But if you insist

Some people put zip ties around the entire unit (including the top part) so that the zip ties will take the damage and not the unit.
I've also heard that the instructions are bad for the 5-10mm part. Just make sure that the chain is never more than 30mm away from the sensor. Check this in the big - big combo.

http://midweekclub.ca/powerFAQ.htm
I hope the second link works;
If not use search on
polar power sandiway fong
http://www.google.com/search?client...=sandiway+fong+polar+setup&btnG=Google+Search

 

Mike,

The instructions say specifically that the spacing should be 5 to 10 millimeters "when the chain is in the small front chain ring and in the small rear cog". If you go by those instructions, there is no way the chain can get any lower. That, however, may cause the distance between the chain and the sensor to be too high when you're in the largest chain ring (especially if you have a triple). I installed mine so that when I'm in the smallest chain ring, smallest cog combination, the chain does rub the sensor. However, once the chain is under tension, the rubbing is very minimal and there's no real damage to the sensor (it does get dirty and scuffed up).

The following is one of the best resources on the web related to power meters in general with a Polar emphasis:

http://web.archive.org/web/20030609112142/mywebpage.netscape.com/rechung/wattage/

There are photos of some good installations at:

http://web.archive.org/web/20030422.../rechung/wattage/installation/s710photos.html

Take your time installing the sensor and enjoy using it.

Berend

 

In my experience with the Polar Power Kit, especially in terms of getting it dialed in so that you don't get data drop outs when you are using all of your gearing, yeah that drag is normal. A lot of guys use chain stay protective tape, or just clear box tape to cover the top of their sensor. It helps, but it sure looked to me like the sensor is going to get scored no matter what you do unless you are cool with data drop out. On the good side though, I have seen some really gnarly looking sensor with deep grooves in them that are still working great.

 

i put a piece of electrical tape on mine and cutout the small area around the blinking light. i also put 2 thick tie wraps around the unit near each end. this helps minimize wearing grooves in the unit. it only drags the unit when i am stationary at a stop light in the small/small combo (with no chain tension).

 

I looked at the elev. of some of the units on the web links and ITS CRAZY! I have mine pretty much in the 5-10 cm range near the rear and a little higher on the front. I gave it some lift up front yet, not much. I have NO drop offs. Yet, as long as you are getting a steady reading should I worry about accuracy? I hooked it up with a computrainer to test the accuracy and when I'm doing 80-90 rpms it looks pretty good. When you are in 100+ rpms the Polar reads a good 40 watts higher. Who knows which unit is right.

Are there any good reads out there to understand all this data? What are good numbers for Pedaling Index?

 

I have no issues with the power pickup, I have real issues with the handlebar unit plug & socket. Evey ride I end up with data drop out, this is cured by unplugging & re-connecting. There has to be a better way!
Has anyone tried hard-wireing?

 

I have had something similar tothis issue as well. The solution I found was to tighten the wrist strap as tightly as possible because the contacts were moving from the handlebar mount. However it sounds like you have a mechanical issue with the wire plug. If you are somewhat handy with a soldering iron and have a multimeter you should be able to repair this yourself.

 

Thanks for all the advice on rubbing. I haven't been on many hills since I got my Polar power kit, so no need for small gear...yet...

My speed sensor quit after 3 weeks (returned to shop for a new one). I have to admit, installation goes quickly once you get used to it. Any wrenches in LBS should be able to install well after 1-2 units.

Overall, I've been pleased with unit...mostly for getting all my data at once, plus the Polar software is good. No data drops, even on bumpy, salt covered paths.

 

First, if you are looking for the power unit go to heartratemonitorsusa.com. I got mine there for under 250. WOW. Plus, they are great if you have a return or an upgrade. I bought a s520 for my wife and traded it in after a week for the s710. The s520 was stupid. It cleared the data everytime you started a new work out. No memory was allowed but for the last workout. Means if you stop the watch, or the watch gets stopped b/c of electrical interference, you can't restart the watch with a new set. Dumb.

Also, if you are getting a constant read is there any reason to doubt the numbers. People talk about drop offs when the distance between chain and monitor are too much. Yet, is there a possible a problem with the numbers even if you getting a constant flow of data? Plus, are there any good reads out there specific to the data supplied by the polar units?

Thanks in advance.

 

Yes, I do have a very good reason to doubt some numbers. After having my unit for a few weeks and putting in several rides with it, all my numbers seemed to come out fine. No reason to doubt them, yet. On this morning's ride my max power was 3500 and the average was 1300. Something about those numbers seem to be a little off.

I didn't move or bump anything on the unit (speed and cadence were recording perfectly) so I'm puzzled why this happened. Any one out there have an idea why this happened (and no polar wise cracks ) ? I'm hoping that it was just a fluke and that things will return to normal for tomorrow's ride.

 

assuming you didn't just get hold of some testosterone, DHEA, Human Growth Hormone, or do a blood transfusion, i would double check the following:

1). the cadence magnet
2). the position of the large chain sensing unit
3). the connections of the "watch" unit to the handlebar mount
4). the settings for chain length, weight, etc.

i recall once or twice in 2 years having a similar thing happen. i think i just stopped the session (go back to watch mode), then restarted it (hit the big red button). i think this cleared it for me.

 

No, that I didn't....

I have a feeling that is it. When i download the exercises every day, I have to take the watch off to bring it to the computer. If this is the problem, and it persists, I am just dragging the whole bike into my room to do it....

Or get a VERY long USB cable

 

I had the same problem for about a month. The solution was to use a small piece of wood of as a wedge between the wriststrap and the handlebar mount assembly. This forces a more secure connection between the sockets on the back of the watch and the plugs on the handlebar mount assembly. It's impossible to get a really secure connection by just tightening the wriststrap because once the clasp slides through the hole in the strap it always will ease off a little bit leaving a little bit of slack in the wriststrap. That little bit is enough to allow the watch to rattle around a bit when you hit a bump in the road. When the watch rattles around for a long enough duration (one big bump or a series of small bumps) it'll lose power to the power unit because of the intermittent connection through the plugs and sockets, which results in data loss. I haven't had a single data loss event since I started using the wedge 8 months ago. Before then I would lose data almost every single ride.

 

Thanks, I have tried grease in the socket wiggling the socket but I had not thought of the watch connections. Watch this space, thanks.

Gavin

 

Dirt in the connection "sockets" on the back of the monitor will cause problems. I clean mine every time I mount the unit and have had NO dropouts or widely varying power output, other than what I would expect in normal riding.

The only problem I have is with the speed magnet and its sensor, it is too prone to getting upset from my left heel.

 

I had this problem on the right and left side with the polar, but that's just because of I have quite a bit of ankle movement going on, I tend to make the sides of my cranks shiny from rubbing my shoes on them so much.

 

one thing to add to this thread...........i have 2 polar power units installed on 2 bikes. i began to have drop-outs with the newer of the 2 units. after goofing with many theories, i assumed it was a bad wire/connector that attaches to the handlebar mount. i played with it enough and eventually broke the wire. i had to send it back to polar for repair. they confirmed that the unit was functioning properly. i got it back, reinstalled it and the same problem occurred. i called polar tech support and they suggested that i change out the battery in the mount.

voila ! it fixed the problem. i had assumed that since it was almost 1 year newer than my other unit that the battery could NOT have been the problem. i was wrong and could have saved weeks of fiddling around by spending $4 - $5 on a new battery.

 

Does anyone know of someone who can "professionally install the polar power kit" looking at the comments it seems pretty damn hard. Someone in Victoria, Australia.

 

it is really not that hard. i've done 3 installations on my own bikes, and the first one was a little hard. but the 2nd & 3rd went very quickly.

now, polar has a video on their website showing how to do it. it really makes it easier and takes out the "fear factor" which is suppose you have. i know i did, but once i jumped into it, it was simpler than i imagined.