Garmin Edge 305 Review

Copyright ©2006 Trygve Isaacson. All Rights Reserved.

I received the Garmin Edge 305 bike computer that I purchased last week and have a brief review after using it for a few rides.

First Impressions

I was pleasantly suprised at how small and light the 305 is. It's roughly the size of a small candy bar phone. Practically, this means that it's not overly bulky on the handlebars, and that with an appropriate armband (Garmin does not have one) it should be small enough and light enough to wear running.

Compared to an iPod Nano, it's the same height, slightly wider (mainly due to the buttons on the sides), and thicker (a bit thicker than a full-size 3G iPod). The size is absolutely no problem on the bike.

The display is reasonably large given the device's nice compact size, and has a fairly configurable layout. You have to balance how much data you want displayed, because the more fields you show, the smaller each one is, and the harder it is to read while you're riding.

Data can be transferred via USB to a computer, and the supplied PC software keeps a log of your workouts and can graph the data, although the map display is only rudimentary. There's non-Garmin-supplied software for Mac OS X that will transfer the data to the computer and save it in XML and Google Earth formats.

Cadence Setup

The optional GSC10 cadence sensor works well. My previous experience was with wired cadence and speed sensors, which had the problems of running cables from the handlebar mount to the sensor, and risked the cables getting damaged. I suspect that a short-circuit in the mounting bracket is what caused my Avocet 50 speed sensor to become unreliable. A wireless sensor like the 305's eliminates all of these problems, assuming it's reliable.

Because the GPS part of the system detects the bike's speed, the speed sensor is only used if the GPS signal is weak or the GPS functionality is turned off (for example, if using a stationary trainer).

The sensor has another advantage over those like the Avocet 50's in that it has a speed and cadence sensor together in one unit rather than two sensors at two locations on the bike. Many others have a sensor on the front of the bike (for example, a ring magnet on the front hub, and a sensor on the front fork) for speed, and a sensor on the back of the bike (magnet on the left crank, sensor on the chain stay). That's two places to run wires, two wire to get loose, gather grime, and short out. The GSC10 sensor is simply placed on the chain stay, with a magnet on the left crank for cadence, and a magnet on a spoke for speed. And no wires!

I have one complaint about the extra sensor unit, which I bought from an Amazon.com third-party seller. The sensor did not work. I tested the battery and determined that it was only putting out 1.5V instead of 3V. After picking up a replacement battery at Radio Shack for $4, it worked fine. I was tempted to blame the seller, especially since the Garmin retail box was not factory-sealed; but the stuff packaged inside the box was clearly brand new and never opened.

The 305 flashes a little pedal icon to indicate whether or not it is picking up data from the cadence unit.

The speed and cadence values appear for each sample point in the GPX XML data when exported.

Heart Rate Monitor Setup

There's nothing you need to set up for the HRM. You just strap on the chest band and go.

However, if you want, you can configure the 305 to customize the heart rate "zones". These let you define your workout in terms of where you want your heart rate to be for different periods or intervals. In the software you can see how much time you spent in each heart rate zone. The 305 can be set to beep if you fall below a certain heart rate; it's the equivalent of a coach yelling, "Pick up the pace, you slacker!"

The 305 flashes a little heart icon to indicate whether or not it is picking up data from the chest band.

The heart rate value appears at each sample point in the GPX XML data when exported.

Realtime Data Display

The mode button cycles through four screens:

• Configurable data screen
• Route track screen
• Elevation profile screen
• Setup screen

Configurable Data Display

The realtime data display is configurable as two independent screen layouts. You can flip between them by hitting the enter button. Each screen can be configured to show whatever data fields you want, with up to 8 fields on each screen.

The fewer fields you choose to display, the larger each field is; the display makes the best use of space it can with the amount of data you've chosen. From my use so far, I think the best way to configure it is to put your favorite 5 fields on the first screen (this allows one very large readout), and then put some less important fields on the second screen.

There following real-time data fields can be displayed at any location on the screen, subject to those space limitations:

• Cadence
• Cadence - Avg
• Cadence - Lap
• Calories
• Distance
• Dist - Lap
• Dist - Last Lap
• Dist - Paused
• Elevation
• GPS Accuracy
• Grade
• Heading
• Heart Rate
• Heart Rate - Avg
• Heart Rate - Lap
• Heart Rate Zone
• Laps
• Speed
• Speed - Avg
• Speed - Lap
• Speed - Last Lap
• Speed - Max
• Speed Zone
• Sunrise
• Sunset
• Time
• Time - Avg Lap
• Time - Lap
• Time - Last Lap
• Paused
• Time of Day
• Total Ascent
• Total Descent

That's a lot of available data to display. If you select 5 or fewer fields, the top item is very large, and the rest are uncluttered, so it's fairly easy to read at a glance while riding. With more fields, it starts to get harder to pick them up quickly while riding. You don't want to have to take your eyes off the road for more than a moment.

The following is a two-screen configuration that I think works pretty well for what I want to see while riding. You can see how the first screen looks in the size comparison screen shot above.

First Screen:

• Large Field: Speed
• Cadence
• Heart Rate
• Distance
• Total Ascent

Second Screen:

• Large Field: Time
• Time of Day
• Speed - Max
• Elevation
• Grade

The first screen has the most import real-time data. If I want to check the clock, see how long I've been riding, my top speed down that last steep descent, etc., I just hit enter to toggle between the screens.

Route Display

The next screen shows the GPS route, much like you would see on a traditional GPS. However, because the display is rather small and there is no map data, this display seems pretty useless. So far, all I've seen is a tiny dotted line showing my route and current direction, without any landmarks or waypoints.

The user manual describes a way of inputting waypoints, but this seems of little value, unless you plan to ride to unfamiliar locations using the GPS mainly as a compass!

Altimeter / Elevation Profile Display

The next screen shows an elevation profile graph. It's kind of neat to see at first, but I think it's really more a novelty than anything else. Seeing your climbing accomplishment as you ride is fun, but when you're climbing, your body is already telling you what the screen shows. I suppose it would be gratifying to look at afterwards, although the equivalent data shows up on the computer when you download the data.

One interesting thing I found is that the altimeter reading of the 305 did not quite agree with the elevation profile that Google Earth used to display the route when I exported the data to GE. The result was that when GE displayed the route, it would disappear beneath the road in certain hilly spots. It may well be that GE is incorrect by a few feet, or that the 305's altitude data was not correct to the last few feet. Fortunately, the software that exports to GE (read below) has a checkbox for inclusion of altitude data, and by excluding the altitude data it means that GE uses its own altitude data. I presume the checkbox is there for this very reason.

Using With Two Bikes

Obviously this is only an issue if you are using a GSC10 sensor on two bikes. I put a sensor on my road bike and my mountain bike, and was surprised that it automatically picked up each sensor's output automatically.

The configuration of the 305 lets you identify three bike "profiles". A bike profile consists of the bike weight, whether it has the cadence sensor, and the wheel size (which can be set to auto-detect). The bike weight presumably has an influence on the calorie-burning calculations. I imagine that the wheel size is used to determine a correct speed value from the speed sensor when the GPS is turned off or the GPS signal is weak.

I don't yet see how to tell the 305 which bike profile you want to use for your workout. But so far it seems to have no trouble pairing with the cadence sensor on whatever bike I ride.

Battery Charging

The 305 simply has a mini-USB port, and it comes with a wall charger that has a mini-USB plug to charge the 305. You can also charge it by plugging it into a computer's USB port if the port supplies power.

I like this trend we're seeing, where devices provide a USB port for power and charging. My cell phone also gets power via a mini-USB port, so that's two devices that can share wall chargers, car chargers, and can get power from a computer. The iPod is almost like this, except that the dock connector end of the USB cable is different, but a mini-to-full USB adapter would even bring it into the fold.

Garmin claims a 12-hour battery life, less if using the wireless cadence or HRM features. I've never really tested it to the limit, but for a 3+ hour ride it has never complained, even with cadence and HRM at the max sampling rate.

Data Transfer / Computer Software

The USB cable is the transfer mechanism. The included PC-only software is reasonably functional, although it exhibits the standard Windows ugly user interface, jaggy fonts, primitive graphics, and general clunkiness that you expect from most Windows applications. The software lets you download the data and save it on the PC. You can see a map of your ride, although the underlying map information is very sparse; you won't see any streets, just cities and major highways you cross. You can see a 2-D graph of several data elements overlaid. For example, you can see your speed graphed against altitude, heart rate, and so on.

Here's a screen shot. The street map you see at this zoom level is about as detailed as it gets. If you zoom in further, there are no additional streets shown.

For the Mac, Garmin doesn't yet supply any software (promised for Fall 2006 after previous delays), but there are free programs that will download the data and do interesting things with it. For example, a program called LoadMyTracks will spit out either a GPX file (an XML-based GPS data standard) or a Google Earth KML file (also XML-based, although the route coordinates are just a big run-on sentence list inside a single tag). It's pretty cool to export your workout to Google Earth and fly it! This is not something the Garmin-supplied PC software does.

For example, here's a Google Earth map of the first long bike ride I took using the 305. This file was initially generated by LoadMyTracks. In Google Earth I added comments, selected a color, etc., and then did a Save As. (Save this file and open with Google Earth.)

I would love to see a Mac program that would save the 305's data as a workout journal, like the Garmin software does, but with a nicer UI and taking advantage of CoreGraphics to produce some really outstanding charts. A bonus would be uploading to a web site ala Garmin's "Motion Based" service, but again with a better eye for design and usability, like the Nike+ site.

Summary

The Garmin Edge 305 is a very good all-in-one cyclometer and heart rate monitor with a wireless cadence and speed sensor for the bike. It's small and light enough to be worn while running, too. When compared with a GPS device that you might find in a car, the display is constrained by the small device size you want on a bike, but it uses the screen to good effect, with a configurable multi-field display and reasonably large text.

It can be purchased with or without the cadence and HRM options, and the cadence unit can be purchased separately for use with multiple bikes.