Product Comparison: GPS Computers

13 12 2010

A couple of months ago, I noticed that my bike computer was dying. It lost a line of crystals down the centre of the screen and would get stuck on the language selection screen in the middle of a ride.  After thinking about what to replace it with I finally decided to get a GPS computer. Originally I wanted to get the Polar RS800CX with cadence and foot pod, but it was a cost I just couldn’t justify.

After a little research and some bargain hunting online, I ended up at wiggle, where I found a Garmin Edge 500 (GPS-enabled super cycle computer) for $310. At that price it came bundled with a cadence meter and a Team Garmin-Transitions jersey. The best I could do in Australia was $299 without delivery or cadence meter (let alone the jersey).

Garmin Edge 500 (& Jersey)

After the Garmin arrived, I tried to install the old computer on the hybrid. I figured I only used it for scooting around town and to and from work, so it wasn’t a big issue if it dropped out from time to time.

I was wrong. When you don’t wear a watch, and you’re used to checking the time on the bike computer, it is a bloody nuisance when it breaks down. So I went online shopping again, this time for a budget, entry level cyclocomputer. I had intended to get something with just the very basics – clock, time, speed etc. Knowing I wanted a bargain, I went to one of my very favourite online shops – Cell Bikes. In the process, I found this – the MainNav MG-600. It’s not a cycle computer but a Sport GPS Datalogger. Which is to say it IS a GPS cycle computer, they just ain’t calling it that. Price of the MainNav – $79

MainNav 600

Both units are pretty much the same size, and both came with a bike mount kit.

Side by Side -Top View

Side by Side - Profile View


The MainNav also came with a chunky wrist kit, which makes it fairly easy to use on a run. Of course, if you happen to run with a bag, spibelt, pockets etc, you can still take it with you, but you won’t be able to easily read it as you go.

MainNav wrist band


The screens on the units are pretty similar in size, but the resolution on the Garmin is much better, and is therefore easier to read. Having said that, the MainNav has an automatic backlight function which comes on automatically in lowlight conditions. With the Garmin, you have to hit a button to activate it, although you can choose for it to stay in permanently if you wish.

The Garmin comes with a host of features that the MainNav doesn’t have, and for four times the price you’d expect it to. Heart Rate and Cadence are the biggest, most obvious features (although you have to pay extra for the cadence meter), but it records temperature, has a virtual partner, and allows you to ride against previous course and times. Even better, is the highly customisable screen, so you can choose what info is displayed on each of the three screens you can use. Plus the unit just looks better. It has a shinier, prettier casing which looks a lot nicer than the utilitarian appearance of the MainNav

Having said that, the MainNav does the job. It has the basic features (time, distance, elevation, maps) as well a couple of things the Garmin doesn’t. One is the waypoint marker. Just hit the button as you are travelling and it will mark your location, so when you look at your final data you can see more than just the start and finish. It also has the “behind” feature, which tells you when your speed is below the average for the trip. I haven’t actually used this feature, but it’s good to know that it is there.

The biggest fault with the MainNav is the interface. It’s clunky. The Garmin makes sense – the menu system is sensible and intuitive, but with the MainNav, I feel like I’m bashing through doors hoping to find the right room.

The MainNav connects to the satellites marginally faster than the Garmin. Once connected, both units do a sterling job. The Garmin uploads direct to the internet via Garmin Connect, whereas the MainNav comes bundled with it’s own software (that only works on Windows).

Once logged on, Garmin Connect easily reads and uploads you data with a single mouse click and all of your data (past and present) is available to you. For each route, you can easily see your map, basic stats, as well as graphs of speed, elevation, temperature, heart rate and cadence. There is an option to export the data in a variety of formats or you can choose to upload it to Google Earth (I assume for a 3D flythrough). Essentially, it is a very useful and user friendly site. Garmin Connect is also recognised by a number of online sites – mapmyride, mapmyrun etc. The biggest issue with Garmin Connect is the need to register beforehand and the need to have an active net connection everytime you want to view your data.

Garmin Connect Screenshot


With the MainNav, everything is done offline – as long as you have downloaded Google Earth first. The biggest issue with the software is the mumber of steps involved to get your data into its final state – plug in, select timezone, download, delete used file, send to Google Earth. With the Garmin, it is all done in a single mouse click. Add to that the the instruction manual for the MainNav software is written in bad English, and it takes a while to figure out. Truth be told, it wasn’t until I’d had it for nearly a month before I had it all figured out, and that was only after a manual delete of all the data on the unit and the release of an “instruction” video by the manufacturer. But once you get it sorted out, the info is great. Google Earth is a great program and the information it provides you is excellent. The following picture is data from the MainNav after a return trip run (with work in the middle)

MainNav-Google Earth Screenshot


If you just use the units as basic cycle computers and only want speed, maps and elevation, then the MainNav wins hands down. It is a quarter of the cost, and does each of those things as well as the Garmin as well as a few things the Garmin doesn’t do.

If, however, you are interested in HR, cadence, virtual partner, customisable screens, temperature (and a host of other features), then the Garmin wins hands down.

All said, I’d buy the Garmin if it was in the budget, but I wouldn’t hesitate to buy (or recommend) the MainNav if the budget is tighter.




2 responses

13 12 2010

Thats pretty cheap (the mainnav). My Garmin came with two mounts, so couldn’t you have just used it on both bikes?

12 01 2011

You description of the user manual for the Mainnav doesn’t go far enough. The word “Painful” doesn’t go far enough. The online video isn’t much better. It’s too rushed. It’s a shame because the unit itself is magic. It just means a lot of experimenting because of the bad manual, and the comments section on their website doesn’t work!!! Good trick.. no complaints then!! PLEASE MAINNAV, review the manual.

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