Inconsistency between Speed and Average Speed

[jrfalck]

Hi,

While doing a ride after a few minutes I was steady at about 20-21 MPH. The Average speed meter in the dashboard was reading 17.1 MPH. I found it normal it probably was considering the initial speed from zero. After an about an hour at 20 MPH the average speed meter still showed 17.1. I decided to test it so I increased speed to about 25-26 MPH until the average speed change to 17.2. When it did, I returned to 20 mph, making sure it never went below 19 mph. Yet after a few minutes Average speed went back to 17.1

When dividing distance over time the average speed was correct. So I can think only two options:

1- Actual speed shown in the dashboard is wrong (higher than real)

2- The distance covered is not correct relatively to the speed.

Let me know if this is something from my side that I need to adjust, since the numbers I explained above otherwise don't make sense.

Thanks!

[admin]

Ok, I set up completely flat ride.

I then proceeded to ride at 51 watt power that after some stabilization period (11 min) gave speed 19.2kph and average speed of 19.1kph. There was no point waiting for those to become completely equal.
I have then increased power to 101 watt which after a short while stabilized speed at 25 kph. Average speed started growing immediately. At 44min mark it had reached 23.6kph. I have then reduced power down to 75 watt that had speed stabilized at 22.5 kph. Average speed started to fall and got down to to 23.3kph at the end of the ride.

So here we have short summary

Code: Select all

total ride time: 11min - power:  51W - stabilized speed: 19.2kph - average speed:  9.1kph 
total ride time: 44min - power: 101W - stabilized speed: 25.kph - average speed: 23.6kph distance - 17.3km 
total ride time: 59min - power:  76W - stabilized speed: 22.5kph - average speed: 23.3kph distance - 22.9km

And verification (calculate average speed from on screen riding time and distance)
3.6*22900/(59*60) = 23.2888 kph
I consider 23.2888 kph calculated vs 23.3 kph on-screen as a very nice match (may not always be that nice given rounding/truncation of values for easy display purposes)

So nothing like you have just described even though the spirit of your experiment was kept.

After that test I had selected some rolling hills ride and rode at steady power of 200 watts for 50 minutes. Due to varying terrain the speed was obviously going up and down. Long story short:

Code: Select all

total ride time: 50min - power: 200W - average speed: 31.2kph - distance: 26km

And verification (calculate average speed from on screen riding time and distance)
3.6*26000/(50*60) = 31.2kph
so on screen average speed and calculated one is in total agreement again.

So I am not sure how you managed to get the results. One thing though, let me know if that was a Computrainer you were training on. There might be some funny things with that trainer in particular. Also pleas give me name of the video you were riding and send me TCX file. Forum does not have attachments so email it to kostya@veloreality.com . Before you do go to our web site, fill out contact form and wait for my reply. This way your email address will be Ok'ed by our spam removal.

[jrfalck]

Yes it is a computrainer. I was riding Utah Potash Rd. Thanks!

[admin]

It seems that I have an issue with Computrainer handling code that I am currently investigating. Since we no longer have access to Computrainer we can only try to fix and test using live connection to client computer. So if you want this investigated any further/fixed contact me for live support as explained in: https://veloreality.com/forum/viewtopic ... &t=94#p296

[admin]

It seems that your problem is a result of some incorrect calculations in Computrainer's driver. It has also caused the problem reported in: https://veloreality.com/forum/viewtopic.php?f=4&t=429 . New release 1.5.0.135 contains among the other things a fix for this problem.