The Garmin Forerunner 405CX is a heart rate monitor watch that is based on the Garmin 405 model, which I have previously reviewed. Both watches have very similar features. Both have the same slim and sleek watch face, and are among the more fashionable models from the Garmin lineup. The same touch bezel is present on both watches, which act as an iPod style scrollable wheel interface. Both are loaded with serious training features, including GPS tracking and heart rate monitoring capabilities, so you can track your distance, pace, heart rate, and time during your jogging or biking sessions. Both also have the ANT+ wireless technology, so you can transmit the data wirelessly from your watch to your PC or Mac, and have the data analyzed with the Garmin Connect and Garmin Training Center software. With either watch, you can race against a Virtual Partner, or race against yourself from a past training session.
The Forerunner 405CX costs about $30-70 more than the Forerunner 405. What is the difference between the Garmin Forerunner 405 and 405 CX? Comparing the Garmin 405 vs. the 405 CX, one finds many differences. The major difference between the two watches is that the 405CX does calorie calculation not based on your distance and speed (the way the 405 does calorie calculations), but rather on your heart rate, which is a more accurate way to do it. In addition to this fundamental difference, there are also several important cosmetic differences. For example, the Garmin 405 comes in black and green colors, whereas the Forerunner 405 CX is available in the more popular deep blue color. And the 405CX comes with an additional smaller and shorter Velcro watch strap, which is more suitable for people with smaller wrists. The alternative Velcro watch strap is fabric, and is more comfortable than the original plastic one.
Overall, the Forerunner 405 CX is a well-designed watch. However, there are some minor faults. For example, the 405CX’s touch bezel becomes unresponsive when it gets wet (as does the 405’s touch bezel). The touch bezel is fine, and becomes responsive again when you dry it, but this means that you cannot adjust it on the fly if you are running in the rain, or if you sweat profusely during your training sessions (unless you keep toweling it dry). It is also quite difficult to swap out the provided blue plastic watch strap for the smaller fabric watch strap. The operation requires pushing two spring bars on each side of the strap with a provided spring bar tool, and is a rather delicate task requiring some manual dexterity. And it is somewhat disappointing that Garmin has chosen to provide the fabric strap in black rather than a blue to match the watch face.
Still, these minor imperfections are not enough to outweigh the fundamental strengths of the watch. The GPS receiver is sensitive and acquires a lock quickly. Once the lock is acquired, it is also remarkably difficult to lose, even when you jog close to trees or buildings. The watch face can be easily configured to show any two or three pieces of data. And additional data is just a touch away. All in all, the Garmin Forerunner 405CX is a solid and well-built watch, and is a worthy companion for your workout.