Why use speed sensor for biking
The simplest way how to track your speed is by GPS. It works with all vehicles even with human legs. Unfortunately, it doesn’t give always precise results. Sharp curves are not sharp and what if get inside a building or to the tunnel? For accurate results, you need a speed sensor.
There are two main advantages of speed sensor:
- Faster reaction to acceleration and deceleration
- Is more accurate
When GPS calculates speed it doesn’t work with the most recent data. Between each measurement, there is a delay. Results are averaged and do not react fast enough to acceleration and deceleration. I hate this when I’m running and to keep my pace I use primary my feeling than my watch. With running, there is no sensor to help you. On bike … that’s a different story.
Speed sensor on the bike works on a simple principle. A circumference of a wheel is a fixed value. On one turn it always moves the same distance. Now you just count how many times wheel tuned in last second and heureka, you now speed of your bike. You will see changes in speed immediately.
There are some things you should keep in your mind. It will work if:
- You carry your bike.
- When a wheel is not on the ground and it is spinning (eg. when you jump)
- When you set the wrong circumference of your wheel. This can have a huge impact. To count it right you need a size of your wheel and tire. This table is handy.
Apps support is bad. Really really bad. For example, Strava one of the most signification bike apps does not support it and do not willing to do it in future. The reason is simple. They count speed strictly from GPS coordinated. It might be because of Strava segments. They use their own system to improve the accuracy of GPS data.
The same issue is with Endomondo. They don’t support it. The would be to use the app provided by the manufacturer of your sensor.
This incompatibility was a big surprise for me. On the other side, I understand. GPS metrics speed and distance are in core system and it might be hard to override them with some sensor.