Back on the Road with the Polar S625X

Earlier today I tweeted that I had found my Polar S625x and I was able to get it working with the speed and cadence sensors that are installed on my Trek 1500 before I rode it this morning.

This heart rate monitor is my favorite of all the models I've ever tested. The things I like most about it are its near indestructibility and its flexibility in that it works well in the three sports that I participate in most.

I started talking about the S625X on January 26, 2005, which means that I've been using it for over four years without a battery change or any service to the receiver. Over that time, I've ridden hundreds of miles on my bikes with the S625X strapped to the handlebars. I've also worn it during many hockey games, which is a great statement about its durability-- it's taken more than one direct hit from a puck.

The main claim to fame of the S625X is its support for running. This is accomplished through the use of a footpod which measures foot strikes and imputes distance traveled based on that. I don't care as much about accurate distance measurement when running as I do when cycling. I tend to run the same courses in training and measured distances in the 5 and 10k races that I run in from time to time.

The speed and cadence sensors for biking are simple to install and use. They simply measure how many times the front wheel and crank of my bike rotate by counting the number of times small magnets pass each of them. The sensors transmit their telemetry to the watch unit which acts as a receiver.

About all I can say that's truly negative about the Polar S625X is that the software that came with it, Polar Precision Performance Software Version 4 is out of date and only runs on Microsoft Windows. If you buy it now, you get newer software that's still Windows-only. I am hoping to start evaluating iSmartTrain from OTAG Technologies that provides similar functionality on Mac OS X, but I need to find the most compatible interface for it. iSmartTrain describes that as "a Polar IR-Serial interface and a USB-Serial converter".

I don't see the Polar IR-Serial interface on sale in a lot of places in the USA, so I'll have to ask where it can be purchased.

If you have any suggestions for where I can buy the IR-Serial interface, email me at daiello [at]