Hello. I have a Bolt 2. When I first installed it I did not have the speed sensor installed. It seemed to calculate speed anyway, with what I assume is GPS.
I installed the speed sensor and linked it. Now my distances are a couple of percent different.
Which way have you found to be more accurate?
Is there really a reason for the speed sensor?
Thanks
If everything is set up correctly (wheel circumference matches the tire at current rider weight, pressure and wear level) and there are no signal drops, a speed sensor will be more accurate than GPS because GPS-based speed/distance is calculated based on location every second, and every turn will result in calculated distance shorter than actually traveled because the sample describes a set of straight line segments rather than the curve actually traveled.
But things are never set up correctly. I use a speed sensor and if the mileage on a segment I regularly ride is slightly too high, I check the tire pressure.
Also, GPS location accuracy can be compromised by tall buildings or heavy tree cover, and that will affect calculated speed/distance.
GPS also exhibits position wander, so sitting still, your position will move around. This is interpreted as some low speed which can add/subtract from you instantaneous speed, throwing off features like auto-pause. I have speed sensors on all my bikes. Most recently, about a year ago, I got a Magene S3 sensor for $17 on Amazon and it has worked well. These can also be attached to a crank and configured as a cadence sensor instead.