The Edge 520 Bike Computer, Garmin's latest addition to the head unit game, expands on the functionality of the Edge 510 with the ability to display metrics encompassing everything from charting fitness levels to power output and targeted recovery. It's also the first head unit to feature a live connection to Strava, which means you can track segments in real time from the saddle. As you might expect, it features all of the standard functions included in the lower numbered Edge models, but the key changes mentioned above are what recommend the Edge 520 as a personal guide to the extreme edge of endurance training. With the advent of the 520, Strava is now a constant presence on our rides. We like the 510's Garmin Connect segments, but let's face it: when it comes to informal KQOM competitions, Strava's the real battle ground. The 520's direct connection to Strava gives you an edge in that battle because the segments update live as you ride, simultaneously displaying the stats of your present performance against the current KQOM and your own personal record. In addition to just being a lot of fun, live Strava connectivity also provides more structure to training and race prep by keeping us constantly linked to an external referent, allowing for data parsing and adjustments on the rides themselves, not just in between them. The list of parse able, power related metrics has also expanded compared to the 510, so the data nerds get as much of a win as the Strava junkies. For us, the big star here is that, when paired with Garmin's Vector or Vector 2 power meter pedals, the 520 calculates your functional threshold power FTP. Once equipped with an FTP, you'll be able to calculate ideally timed and measured efforts for intervals tailored to your own fitness level. Instead of burning out trying to hit arbitrary output numbers, knowing your FTP helps you stay at a level that's more effective for increasing your present level of fitness. After all, the real point of i...