Problems with Polar computer

My polar cs100 keeps giving me erratic speed readings, or sometimes none at all. Anyone else had this? Also where is the magnet supposed to be in relation to the sensor, is it supposed to pass the top, bottom, middle or what?

Jumpy

I havent seen the sensor for one of these, but you should keep it as close to the center as possible with most magnetic sensors.
Try and ensure that there is a minimal gap between the sensor and the magnet when the wheel spins.

Also ensure that if the magnet ever hits the sensor that it will push it away rather than catch it into the spokes. Things could get messy if you dont.

Yup, it's real close and it pushes it away when it hits it. Problem is when the magnet is passing the centre of the sensor it gives no reading, only seems to work when I slide the magnet down so it's passing quite low in relation to the sensor. Works fine when I grab the wheel and spin it at home, but when I'm out for a spin it might read something like this as I accelerate coming of the crest of a hill or whatever: "28 ,30, 35, 38, 12, 24, 35, 50, 23, paused"

It's doing my feckin head in!

DirkVoodoo

How far up the fork is the sensor placed. I had to place the sensor further down as I was getting similar problems, the closer to the rim the magnet is the faster it will be passing the sensor. I don't know why I was having this problem though, most sensors are placed fairly closer to the rim than the hub.

I'm the other extreme, down near the end of the fork. Could that be the prob?

DirkVoodoo

Deleted User wrote: »

I'm the other extreme, down near the end of the fork. Could that be the prob?

I'm not sure on what the transmitter range is on the polar sensor, but yeah they are generally placed closer to the rim. Give it a try and see what happens.

blorg

Deleted User wrote: »

I'm the other extreme, down near the end of the fork. Could that be the prob?

Should be OK either way, arguably more reliable towards the fork due to the lower passing speed. I have similar frustrating issues with a Tacx trainer cadence magnet but have have never had an issue with a Cateye, they just work.

DirkVoodoo

DirkVoodoo wrote: »

I'm not sure on what the transmitter range is on the polar sensor, but yeah they are generally placed closer to the rim. Give it a try and see what happens.

Ya might as well, nothing to lose. Where can one buy cable ties? (that's what hold's the sensor to the fork and I have to cut them if I want to move it)

DirkVoodoo

I actually have no idea, Woodies or somewhere similar I guess. Make sure to get the right size, they are pretty narrow IIRC.

lescol

I have the S series Polar so the solutions maybe different.
The sensors have a light that comes on for the first minute or so to show it's working, there's also an audible "tick" as the magnet passes.
If the battery in either the sensor or the monitor run low readings become increasingly erratic.
Is the sensor within range of the monitor with nothing to get in the way? In the S series it's easy to increase the range. Make sure the monitor and sensor are both on the same side of the bike.
Water in the sensor screws them.
Is the sensor remaining in the same place as you ride? Bumps can cause them to move just enough to put them out of range of the magnet.
If all else fails return it to Polar, they will usually replace it, and post here:- http://forum.polar.fi/forumdisplay.php?f=52

SMacX

It could be your lights causing the problem.

I have a Sigma Speed and Cadence and when I have a super bright light on the handlebars the computer goes bananas....

Have a look and see if its the lights, if it is, get a corded version of the computer. Thats the only advice I was given, not even any idea on how to shield the light, stop the interference nadddda....

Good hunting

chakattack

I got the CS200 cad for Christmas and was tempted to burn it!

I had the same problem with stupid speed readings. 0 most of the time with intermittent 15kph on a fast downhill or 45kph when climbing!

The solution: Get new cables ties and install the sensor as far up the fork (toward handlebars) as possible.

It works now but it seems like the sampling rate is very low. It seems like the speed updates every 10-20 seconds so it's hard to gauge acceleration in real time.

I was using a Cateye Strada Wireless and it was much much better for speed.

To be fair the HR monitoring is very good.

zzzzzzzz

Polars customer service/repairs department is really good. Contact them and send the unit back to them i'd say.

Thanks everyone for the replies. I think I'll try moving the sensor further up the fork, hopefully that might help.

shergar22

chakattack wrote: »

I got the CS200 cad for Christmas and was tempted to burn it!

I had the same problem with stupid speed readings. 0 most of the time with intermittent 15kph on a fast downhill or 45kph when climbing!

The solution: Get new cables ties and install the sensor as far up the fork (toward handlebars) as possible.

It works now but it seems like the sampling rate is very low. It seems like the speed updates every 10-20 seconds so it's hard to gauge acceleration in real time.

I was using a Cateye Strada Wireless and it was much much better for speed.

To be fair the HR monitoring is very good.

I had the exact same problem, flying along the road and then 0 for about a minute. Nearly bloody ended up in the ditch because I was watching it so much.
I wasn't sure if it was the rain (heavy mist) or was I getting electromagnetic interference from my Magicshine. I had the battery cable wrapped around the handlebar next to the computer. Looking up on other forums it appears to be a common problem, in particular with power lines etc. However, since then I've had no problems the next few times out.
According to the manual, the max distance between computer and sensor is quite small, so closer up to the rim would do better.