27 replies to this topic Post Order

[bruce]

I set up my bike on the computrainer with both the PowerTap and Ergomo devices on it.  I then used the computrainer in ergo mode to step power 50 watts every 30 seconds from 150 watts to 350 watts.  These are the results, very close!

[smallrebel]

What happend between 1 en 2.

[bikemonster]

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What happend between 1 en 2.

 

Nothing, evidently.

[smallrebel]

If it was Marius it could be a broken spoke, flat wheel (but then the line will be flat for longer).

[bruce]

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What happend between 1 en 2.

I stopped pedalling briefly, can't remember why.

[Mervin]

Bruce what is the reading interval settings between the two. It would appear that the Computrainer is averaging the readings.

[Thug]

If I'm reading the graph correctly, it looks like the Powertap is a lot more sensitive.

[bruce]

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Bruce what is the reading interval settings between the two. It would appear that the Computrainer is averaging the readings.

Ergomo is set to 1 second, I think the powertap is 1.26 seconds (fastest sample rate possible)

I'm not showing the computrainer data, just using it to provide a consistent load.

[bruce]

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If I'm reading the graph correctly, it looks like the Powertap is a lot more sensitive.

Ergomo graph is definitely smoother - not sure if this is good or bad.  The display also doesn't fluctuate as much as the powertap.

[Mervin]

Bruce, Has the Powertap been a worthwhile investment and have you seen significant improvement since training with power?

[BikeMax]

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Quote

If I'm reading the graph correctly, it looks like the Powertap is a lot more sensitive.

Ergomo graph is definitely smoother - not sure if this is good or bad.  The display also doesn't fluctuate as much as the powertap.

 

PT display can be set to update slower (smoother) if I recall correctly.

[bruce]

Yes, it can - but it appears that the Ergomo curve is smoother is well, so not sure if the ergomo is less sensitive, or if it is smoothing the data?

Anyway, I need to run alonger test so that I can compare the NP of the two - that is really the important test from a training perspective.

Must say though, that the NP reading I had on the display the other morning was within a few watts of what CyclingPeaks gave me after the ride.

[BikeMax]

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Yes, it can - but it appears that the Ergomo curve is smoother is well, so not sure if the ergomo is less sensitive, or if it is smoothing the data?

Anyway, I need to run alonger test so that I can compare the NP of the two - that is really the important test from a training perspective.

Must say though, that the NP reading I had on the display the other morning was within a few watts of what CyclingPeaks gave me after the ride.

 

There certainly look to be less data points shown on that graph - need to look at the sampling rate of the Ergomo as any smoothing should be done at review stage in CP ?

 

Might be something on CF..

[bruce]

No, exactly the same number of data points - definitely.  Either smoothing or not as sensitive.

Have posted the same graph on CF - thrown it out to the wolves so as to speak!!

[BikeMax]

 

Found this..

 

"Currently, the Ergomo records data every 5 seconds. The Ergomo takes between 72 and 144 measurements per 1 rpm, averages this number over the amount of rpm's per second and saves it. Every second a sample is taken and then 5 seconds (samples) are averaged and this is the number that is recorded in the computer for download. For example: 300w, 300w, 300w, 305w, 310w, will be taken by the computer and the average of these will be recorded= 303watts."

[bruce]

No, that is the old ergomo, the new one is every second here is a sample of the data

0.105	150	184
0.126	163	151
0.147	167	155
0.168	167	163
0.189	162	162
0.21	159	156
0.231	158	163
0.252	159	151
0.273	181	153
0.294	183	205
0.315	184	164
0.336	183	165
0.357	163	159

The first column is time (in minutes) and equates to approx 1 sec intervals, the second column is ergomo watts and the third colmun is powertap watts.