Cadence Sensor Effect?

[lorduintah]

Until this Spring I have used a Garmin Cadence Sensor on my bikes.

As a result most of the time the Power Stroke analysis of my rides has typically shown some asymmetry of the L-R leg action and usually an overall 2 WATTS of power loss.

This Spring I went to a Wahoo cadence sensor and up to now I have seen 1 Watt or less and a nearly perfect circle depicted on the Power Stroke analysis. Also PP reports an average Cadence od 78 and the Gamin shows an average of 106 for the same ride. Battery is in good shape.

I have not done anything to radically improve meriting action, but it would appear - if the sensor does not play a role in the analysis - that I made a great improvement over the Winter indoor riding.

Otherwise, there is a difference in the two sensors, with ia possibility that the Wahoo is less sensitive?

Anyone else happen to try both kinds of sensors and see any differences in the resulting Power Stroke analyses? I should also note that either sensor was mounted on the left crank - so where the sensor is mounted should not be contributing to any issues.

Although I m using a Garmin Edge 830, the PP is paired to the speed and cadence sensors BEORE turning on the Garmin - other wise it could be possible that the PP would pick up the cadence coming out of the Garmin(?)

Will post ride files from both cadence sensors.

Tom

[Velocomp]

PowerStroke works in part by precisely measuring the time between the crank passing-by the same point on the bike.

When we created PS it was simple: whenever the cadence magnet passed by the sensor a signal was sent.

I don't know how either the Garmin or Wahoo cadence sensors work, but I suspect both use accelerometer information. Among other things this could mean that PS timing is more random, resulting in a change in PS shape.

[lorduintah]

John -

Yes - both flavors of these are accelerometer based sensors.

Another question - If I choose to have both the Garmin and Wahoo sensors around, but this is the only difference that will be between two profiles will this work the same way that having two bikes with separate speed sensors and PP will auto=detect which profile to use for a ride?

The Wahoo can be mounted on a bike shoe or through zip ties around the left side crank. The Garmin is mounted on the crank with a rubber band (albeit a strong one). So I could choose to take the Garmin off easily and wear the Wahoo on my shoe - so only one of these sensors would be active and in proximity to the PP.

I still have to get the Garmin configuration - a new Cadence ID is required, so a different Profile/Pairing will be used for that - at least while I figure out if something else is going on and the better stroke performance is an artifact of the Wahoo or the worse Garmin Power Stroke is more realistic - of course, the alternative is that I have improved my pedal strok this year…

[Velocomp]

John -

Yes - both flavors of these are accelerometer based sensors.

Another question - If I choose to have both the Garmin and Wahoo sensors around, but this is the only difference that will be between two profiles will this work the same way that having two bikes with separate speed sensors and PP will auto=detect which profile to use for a ride?

The auto-detect feature looks only at the speed sensor ID. If you are swapping cadence sensors the profile will show cadence data only for the cadence ID stored in the profile.