The Garmin Edge series of cycling computers has been extremely popular among cyclists, and for good reason. They are easy to use, very customizable, communicate with many different sensors, have a plethora of mounting options, make it easy to read data while riding, and store data in a form that can be used with many different programs and services. The Edge 500 was quite popular among triathletes because it offered almost all the features we need and none of the ones we didn't (such as mapping), and did so in a small and compact package at a reasonable price.
The Edge 510 is a nice upgrade to the tried and true Edge 500. It has several appealing new features, including a color touchscreen, cell phone connectivity, and menus that are easier to navigate. After using the old Edge 500 for several years, I was very excited to see how the new model performed, and whether the new features were worth the upgrade.
Why a dedicated bike computer?
The first question many triathletes will ask is whether or not one needs a dedicated cycling computer, or if a multisport watch like the Garmin 910XT would be more suitable. The 910XT is an amazing watch, and as far as multisport watches go, it is arguably the best on the market. The problem, however, is that it does everything, but has to make compromises in order to do so. Compared to dedicated cycling computers, the 910XT's screen is significantly smaller. This has to be done to make the watch comfortable for the swim and the run. It thus can't display as many data fields as a dedicated cycling computer, and can be harder to read at times. Compared to dedicated running watches, the 910XT is larger and less comfortable. This is because the 910XT's battery is significantly larger as it needs to function for a 17 hour ironman. The 910XT is capable of doing it all, but doesn't do it as well as dedicated units.
Garmin's quarter-turn mounting system is quite robust yet easy to use. The unit rotates 90 degrees and locks into the mount. There are dozens of mounting products from both Garmin and 3rd party vendors.
As far as mounting options go, there is also a lot more flexibility with a dedicated bike computer. Garmin cycling computers have used the quarter-turn mounting system for several generations now, and it is quite robust yet easy to use. The unit rotates 90 degrees and locks into the mount. There are dozens of mounting products from both Garmin and 3rd party vendors. Everything from bar mounts, to stem mounts, to aero-bar mounts, to BTA bottle cages with integrated mounts, etc. You can mount it nearly anywhere on the bike that you like. For triathlon, this is great as you can position the unit very far forward on the aero bars, and get it out of the wind at the same time. This leads to less drag and safer riding, as you can usually see the unit without having to take your eyes of the road ahead. It is possible to do this with the 910XT, but it requires a special adaptor, and is much less elegant. You have to remove the watch after the swim and then re-attach it to your wrist after the bike. And you are still stuck with the 910XT's smaller screen.
With a dedicated bike computer, you can display more data fields on the screen at one time, and with the larger screen size, they are still readable. When biking, I like to see speed, heart rate, cadence, power, time, and distance on my main screen. This is not possible with a multisport watch. Using the Edge 510 on the bike is just much more comfortable than using a multisport watch.