Power Pod <-> Footbike Compatibility

[Cyberbob13]

Dear all,

I am not a cyclist in the classical sense but riding "footbikes" - which are basically scooters with a setup very similar to roadbikes (28" carbon wheels, etc.).

To give you an impression how it looks like, I have posted an example picture:



My intention has always been training by power as I was used to with my road and mountain bikes but for Footbikes no solution was available. I scouted the internet and stumbled over the Velocomp PowerPod. It sounded reasonable and I expected it to work also on a footbike as it is simply mounted on the handlebars. So I ordered one and set it up according to the materials provided and did a calibration / test ride.

However, I realized that the power readings the PowerPod provided were all over the place, rather following a wave movement with frequent "zero" readings for a couple of seconds. I tried a factory reset, setting up everything from scratch again but no luck - the readings behaved very similar to the first calibration ride. For your reference, I have uploaded the .ibr-File from the first calibration ride. All metrics worked just fine but the power readings really miss a stable reading (even when using 10s averages on my Garmin Edge 1050). On a side note, it was very windy today with gusts of up to 25 miles per hour. Maybe this has contributed to the outcome but I suspect that the PowerPod - for whatever reason - isn't able to provide accurate / stable power readings for footbikes? I don't care about the absolute numbers (these are clearly understated as footbiking is far less efficient than cycling), but whished I could have more stable readings relative to my actual effort.

Any thoughts or guidance from experienced PowerPod users / experts would be highly appreciated!

Kind greetings from Austria!
Christian

[Velocomp]

Wow, this is the first time in 22 years of running Velocomp someone has asked about using one of our units with a footbike!

The means of propulsion is your kicking the bike forward with one of your legs, while standing on the bike with your other leg.

In principle PowerPod will work very well with a foot bike, but ride files will look much different:

1). Watts are expended only while the kicking foot is accelerating the bike forward. This will appear as a watts spike in the ride file. Zero watts happen when the bike is coasting (not accelerating forward). These are all the dead spots of power in your ride file.

12.png (105.57 KiB) Viewed 58 times

2) When you kick nearly continuously, for example on a hill, you work pretty hard:

11.png (113.06 KiB) Viewed 58 times

3). You used a default profile with standard rider weight of 180 pounds and bike weight of 25 pounds. Is this correct for you?

4) You also have a default profile. Did you do an out and back cal ride? If not, do a ride on a quiet wind day and post it here, so I can check your settings.

5) Because you stand vertically your CdA should be much higher, around 0.6. This will raise your watts from 81.6 to 95.9 . Corrected .ibp profile attached

The only thing I can't assess is possible "flex" of your frame. If your front wheel/handlebars flex as you apply more/less weight to the foot platform, this could affect watts accuracy. I don't see strong evidence of this in your ride file but it is a concern.

Corrected ride file and profile are attached.

[Cyberbob13]

Hi John!

Thank you so much for your comprehensive answer and inputs! Footbiking is quite a niche sport but with a growing community, particularly in Czech Republic, the Netherlands, Germany and some other (European) countries. There are even European and World Championships held each year and quite a few racing series, particularly in Czech Republic. And with increased professional attitude to the sport, a power-based training approach reveals much potential for the PowerPod and its unique proposition.

I have done two out-and-back calibration rides initially and I suspect that the windy conditions and high wind speed volatility could have messed up the calibration process - at least to a certain extent. I also set up a bike profile using the iOS App but obviously that didn't work as expected.

Today, I repeated the calibration process from scratch (still a bit windy but rather stable in terms of strength and direction) and set up the bike profile with the Velocomp Aero Software. The results of the ride immediately following the calibration have been much better:

- Much less and shorter "Zero-Reading" intervals
- Thus slightly less variation / more stable power readings

I have attached a screenshot of the ride as well as the original .ibr file.

Pls. note that there was a very consistent power reading in the second half of the ride (cursor position in the screenshot) with the "wind speed" indicator being stuck at Zero. I am not sure if this was due to riding uphill or simply because of the fact that "wind" was (possibly?) not part of the calculation? In any case, I did not drastically change my riding / kicking style in that section. There are hardly any "cruising" intervals when riding - I always do 10 kicks with one foot, then switching to the other (changing feet requires a small fraction of a second)

Generally I found that strong changes in the wind speed detection did have a very high impact on the power readings (much more than what I felt in "real life"). Do you think that there could be something wrong with wind speed detection?

Best regards and kind greetings!

Christian