John Galea's Blog

My blog on Gadgets and the like

Wahoo bike speed sensor and Wahoo fitness app review

I’ve owned a Garmin combination Cadence and wheel sensor for a very long time. Cadence if your not aware is the rate of rotation of your pedals on a bike. Now if I was a more serious cyclist I would be concerned with cadence, as it is I am more interested in distance accuracy which is what drew me to this sensor. This sensor broadcasts on both Ant+ and Bluetooth. Ant+ can be used to talk to a variety of Garmin devices as well as smart phone apps. But now comes the catch, Garmin did not include a speed only (or cadence only) profile on some of their older models. And some models read, record and then ignore the speed sensor in favor of the GPS. I emailed Wahoo to be sure that my Edge 305 was supported, they insured me it was, sadly it doesn’t work and is completely ignored. On my Fr70 it does work however. On my Foretrex 401 it says right in the manual it will always use the GPS for speed/distance so this is not useful (although I didn’t actually try it with the 401 I have tried others and confirmed exactly what they said, they don’t use it for speed/distance, so ignores it, so why did Garmin bother).

So why would you care? A GPS samples it’s location every so often. In between it assumes a straight line. In a sport like mountain biking it can make a difference in distance. Let’s have a look at a couple runs for comparison. I did two short rides using the Garmin Fr70 with the sensor, and the Garmin Edge 305 using GPS. Even on a road ride the distances were 2.13km Vs 1.83KM or -14% for the GPS vs the wheel sensor. Ride two got 2.18km Vs 1.84KM or -15.5% for the GPS.

Looking at the windy trails of a mountain bike trail I got 28.15km from the sensor and 23.54 from the Garmin Edge (using GPS) or a difference of 21%. The sensor will always be more.

Physically speaking the speed sensor is a magnetless design. It straps around the hub of the wheel and transmits rotation. You tell your device (or app) the size of your wheel and you get speed/distance. The design is brilliant. Well it would be if Wahoo had thought of spoofing it being a speed and cadence sensor which they did not. If your device supports this device it is an excellent choice. If not, as is my case, it get sadly returned. I am a little disappointed in Wahoo support who mislead me about my Edge 305 support.

On my next post I will be covering the Wahoo fitness app that can be used with this and many other sensors!


September 2, 2016 - Posted by | Activity Trackers

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