Winter Cycling - Cyclocomputers in winter time.

Last night my cyclocomputer stopped working on my way back home. Back in the Bike cave it started working again. the outside temp. was about -5 celcius. Is it enough to freeze a wireless cyclocomputer ? It's a Sigma 1009 sts with brand new batteries.

I've used cyclocomputers, including a Sigma, down to -25C w/o a problem. The only problem in one, by Niterider, was that it became difficult to read it in the dark when it was backlit - you had to look at it straight on at low temperatures. Did the readout stop working or did it stop to record the turns of the wheel? When I want to test the working of a device at low temperatures, and it is small enough, I just put it into a freezer.

Looks as though you are operating out of the optimum temp range for this model of computer, if you look at the manual, it give the temp range it works in as 0°-60°C http://www.sigmasport.com/en_media/produkte/bikecomputer/topline_2009/topline_wired/bc1009/allgemein/visuals/ba.pdf See section 7.2

I've had my iPhone do the same thing to me (use it for tracking my rides and music). If it's colder than about mid 40s, I'll leave it in the pack instead of the bar mount. Haven't had any issues with my computer yet.

Usually the screens just freeze up but continue to count the miles so it is nothing I would worry about.

Did it again last night but I don't think it as anything to do with the temperature. I watched it more closely and it just stopped reading the speed and counting the mileage but everything else was ok. the sceen was ok, the clock and all the other data was accessible so nothing to do with the temp.