GPS satellite navigation isn't just for cars and hikers. Specialized GPS units for cyclists are now available. Popular brands include Garmin (Edge) and Magellan.
How GPS Cyclometers Work
GPS (Global Positioning Satellite) cyclometers (bicycle computers or cyclocomputers) are similar to standard GPS units, but there are some differences and optimizations for cyclists.
Instead of using a magnetic sensor on the bicycle wheel, the GPS cyclometer uses its GPS coordinates to calculate speed and distance. This means that no setup is required: no magnet, no wires, no entering of wheel circumference into the computer.
Just like other GPS units, some bicycle GPS computers have a mapping function but not all do.
A standard GPS can be used as a bicycle cyclometer but there will be limitations. Cyclometers need to display speed (speedometer) and distance (odometer) clearly. Standard GPS displays are not optimized for this, often displaying this information in small hard-to-read numbers. The mapping feature for cyclists can also be different.
Advantages of GPS Cyclometers
GPS cyclometers are versatile and easy to use:
- No setup required.
- Can be used on any number of bicycles, not just 2 or 3 like for traditional cyclometers (which need to store the wheel size of the bicycles).
- Can be used with an armband for running, canoeing.
Disadvantages of GPS Cyclometers
GPS cyclometers aren't just more expensive. They can also be less accurate and less reliable. Main disadvantages are:
- Expensive, a few hundred dollars.
- Indicated speed can fluctuate more than with traditional cyclometers, and can be slower to respond to changes in speed.
- GPS can lose track if there is poor reception from GPS satellites: under trees, in tunnels, in canyons (including urban canyons between tall buildings).
- Uses a lot of electrical power. Most use rechargeable batteries but they will need to be recharged every day. Replacement batteries are often proprietary, expensive and need to be changed every few years.
Advanced GPS Features
More advanced GPS cyclometers have features such as:
- Downloading of trip data to PC for analysis (including map of trip, vertical profile), and uploading to dedicated cycling websites.
- Map displays. Either downloaded from CD or SD card (can be expensive), or "draw your own as you cycle." Some CD maps can be downloaded to the PC and GPS, but some SD maps cannot be downloaded to PC.
- Turn-by-turn directions. The directions should be optimized for cyclists: avoiding freeways and prioritizing side roads over main roads.
- Slope incline calculations. GPS measurements of height are possible but often inaccurate. GPS units with a built-in barometer are more accurate for this.
- Auto-lap function to automatically measure lap times after passing a specified location.
- Virtual racing function to race against previous speeds over the same course.
GPS Versus Standard Cyclometers
A conventional cyclometer can cost as little as ten dollars, compared to hundreds of dollars for a basic GPS cyclometer.
Serious athletes can make good use of GPS features such as auto-lap and virtual racing. Casual cyclists may find the mapping function alone to be worth the extra cost. A few hundred dollars is a small price to pay for not getting lost.
Yuen Kit Mun - Kit Mun is a self-confessed information junkie, reading an average of a book a week over the past two decades. His growing Internet ...
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