<< Back to issues

Bug report/feature request

21
votes

Modal Cadence rather than Ave (mean) Cadance

Started by bobthib on Feb 27, 10
I think reporting the modal cadence (the most common value) is more valuable than an "average" (as in arithmetic mean) value. A graph of time vs cadence would be very useful as well.

Comments

No Image
Peter Nelson said
about 2 years ago
Reporting the mode (most common) cadence seems like you could end up with some outliers.

The main issue right now is that 0-cadence points are averaged in, massively skewing the results. On a downhill sprint I was either pedaling at 100+rpm or tucked and cruising. For this section my ave cadence got reported as 62rpm, which is bogus. All 0-cadence points should be thrown out for the calculation, and maybe also points <15 or 20rpm.

Once you only calculate with good data, it'd be interesting to play with mean vs median vs mode. However I see that as a secondary issue.

Also you can add the cadence graph to the main elevation graph, showing you time vs cadence. I'd like to see a summary graph of time spent at each cadence (with ranges of 5 or 10rpm).
bobthib
bobthib said
about 2 years ago
[Reporting the mode (most common) cadence seems like you could end up with some outliers.]

Only in short "laps." By definition over the long run, or a long ride, the mode would avoid outliers.
Jos Odijk
Jos Odijk said
about 2 years ago
Why not breakdown the cadence, like is done for speed ? Split at 5 RPM interval sounds reasonable.
rjedge54
rjedge54 said
almost 2 years ago
Actually for me the cadence is way out of wack. For my Garmin uploads the average cadence is too low as it always reports a minimum cadence of 0.
bobthib
bobthib said
almost 2 years ago
I don't know what cad # garmin use as a cut off, but it's def above 0. I think if they were to ignore just 0 it would be much more accurate.
rjedge54
rjedge54 said
almost 2 years ago
Or they could just use the average value that the Garmin Edge records.
bobthib
bobthib said
almost 2 years ago
rj, that assumes that garmin makes that available as an output. I notice the ave spd is also different so I'm thinking that the garmin export formats only include raw data and not averages, so anyone wanting to use it has to calculate it.
rjedge54
rjedge54 said
almost 2 years ago
From what I see comparing Garmin Connect, the history information on the Edge 305 and Garmin Training Center, the average cadence data is the same on all 3, so I am assuming that this value is available from the Garmin Edge and used by Garmin Connect and Training Centre at least.

I just had a look at the tcx file and see that it is in this file as well so RidewithGPS should be able to use this value.

Here is the value from the tcx file for this morning's ride.

<Cadence>92</Cadence>



rjedge54
rjedge54 said
almost 2 years ago
I had a closer look at the entire tcx file and I think you were correct in your earlier assertion that the 'average' cadence value is not there. I assumed that it was since my initial look only found that once of 92 that match my reported average value. It turns out there were others as well, but I noticed a few 0's so I assume Garmin ignores the 0's and calculates from all values above 0. Either that or it does a calculation based upon the total value of cadence samples it records and simply divides by the number of samples to come up with the average value.
rjedge54
rjedge54 said
over 1 year ago
I had been without my Garmin for the last month as it need repairs for the power reset problem, but now have it back and was about to switch all of my user data over to RideWithGPS but see that this one nagging issue is still there. For this morning's ride my avg cadence as reported by my Garmin Edge 305 and Garmin Connect was 99 which makes sense as I was over a 100 most of the time, and my lowest while moving was 85. The only times I was at 0 was at 2 stop signs and 2 left turns, yet RideWithGPS reports my average cadence at 71. It would sure be nice to get this fixed so I can transfer my historical data over to this site.
No Image
Daniel Rich said
9 months ago
Yup. Average cadence is not a useful number unless you have a fixed gear bike! Cadence below a certain value should be excluded in the algorithm.
You must be logged in to comment...Create an account real quick