Polar CS100 mileage off

[misterE0]

I have a Polar CS100 on my bike and my commute is 11.5mi. Twice, including today, I get to my destination and my distance is way off. Today it reads 19.9mi, and of course, that throws my average speed off as well. Anyone have a similar experience or have any thoughts on how to correct this? Like I said, it's not every time, but it's happened 2x in maybe 3 weeks so far. Thanks in advance.

[misterE0]

bump?

[n4zou]

Sounds like power line interference. Take a small AM radio along with you and listen for 60 Hz popping noise on your next ride. When you hear it look at your wireless cycle computer, it should start showing a higher speed than what your actually doing. The power line interference causes your wireless cycle computer to read that 60Hz signal instead of the little signal produced by your wheel sensor. To try and understand what is happening take your little AM portable radio and tune it for static between radio stations. Hole it close to your wheel sensor and spin the wheel. You should be able to hear a POP from the speaker every time the magnet passes the sensor. Adding 60 pops per second to the sensor input of your cycle computer will cause the problem your having. Thats the reason I always use wired cycle computers.

[misterE0]

thanks for the explaination! I prefer wired as well, wireless doesn't seem to add any benefit, just marketing apparently. But as far as I know, there is no other device that has cyclocomputer, HRM, backlight, and multiple bike support that's also reasonably priced. Besides this issue, I love this computer.

[kingsteve233]

Can power line interference mess with a wired bike computer? I have a Polar S150 (link (http://www.polarusa.com/Products/consumer/s150.asp)) and on one part of my ride it always drops out like it can't pick up the wheel sensor. The path goes right along a power line with a switching station across the street. I had never experienced that with this setup before... but that's sure what it seems like.

I love it so far... having the HRM built into the bike computer is invaluable to me now as it helps me keep better track of my training. I do wish it had a backlight sometimes though..