high power at road bumps

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jonao
Posts: 16
Joined: Fri Jun 28, 2019 10:37 am

high power at road bumps

Post by jonao »

Hi.

Attached is a ride ending at a high power after having hit a bump in the road.
Capture.PNG
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iBike_08_20_2019_1420_12_km.ibr
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(Please, don't bother about the absolute power values, depending on my accepted calibration obviously).

My Powerpod sits tightly on my handlebar, but the handlebar has a suspension in the bike frame to its front wheel,
not being a race bike, but a sporting one.

Did I gather correctly that a suspension move may result in such off power values?
Is there anything to be done preventing such odd power values?
Velocomp
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Re: high power at road bumps

Post by Velocomp »

Yes, what you are seeing is the effect of the suspension on power readings. When you hit a bump your PP momentarily is knocked out of its usual position, causing power changes.

The best way to minimize this problem is to lock-out your suspension.

If you are using your ride files for training purposes, after the ride you can highlight the "bumps" and remove them from the ride file:
Attachments
Screen Shot 2019-08-21 at 11.23.15 AM.png
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Screen Shot 2019-08-21 at 11.22.51 AM.png
Screen Shot 2019-08-21 at 11.22.51 AM.png (734.25 KiB) Viewed 276743 times
Screen Shot 2019-08-21 at 11.22.31 AM.png
Screen Shot 2019-08-21 at 11.22.31 AM.png (145.97 KiB) Viewed 276743 times
John Hamann
jonao
Posts: 16
Joined: Fri Jun 28, 2019 10:37 am

Re: high power at road bumps

Post by jonao »

Thank you, John, locking the suspension not being an option on my bike, I'll have to remove the results - though it would seem rather arbitrary.
jonao
Posts: 16
Joined: Fri Jun 28, 2019 10:37 am

Re: high power at road bumps

Post by jonao »

After deleting the 4 most spurious peaks from todays ride, I now more clearly see a remaining odd power peak when breaking at 27 minutes.
Is it my real acceleration in this case?
I suspect it comes from the suspension generated semi-slope values too.
If so, the Powerpod seems being of no practical use to me as fitted to my handle bar.
Capture.PNG
Capture.PNG (49.39 KiB) Viewed 276721 times
Velocomp
Velocomp CEO
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Re: high power at road bumps

Post by Velocomp »

Nope, that is a real power spike, caused by you accelerating from 10 to 30 km/h.
John Hamann
jonao
Posts: 16
Joined: Fri Jun 28, 2019 10:37 am

Re: high power at road bumps

Post by jonao »

John,
Thank you very much.
I'm glad you could recognize it. Now I can see it too.

Even with that peak as shown I had to remove 50% of the total ride-time/distance to get this plot.
And in today's ride (not shown), again I had to remove half of the ride containing the spurious peaks.

Can such remains still tell me anything about my training?
Last edited by jonao on Sat Aug 24, 2019 11:57 am, edited 1 time in total.
Velocomp
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Re: high power at road bumps

Post by Velocomp »

Please post your unedited ride file so I can take a look.
John Hamann
jonao
Posts: 16
Joined: Fri Jun 28, 2019 10:37 am

Re: high power at road bumps

Post by jonao »

today's ride
iBike_08_24_2019_1146_34_km.ibr
(251.63 KiB) Downloaded 632 times
Velocomp
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Re: high power at road bumps

Post by Velocomp »

jonao wrote: Sat Aug 24, 2019 2:38 pm today's ride iBike_08_24_2019_1146_34_km.ibr
Your unit is not calibrated; you have a default value of wind correction in your ride file. Load the attached profile into your device.

I deleted the first 5 minutes of your ride, then used a trick to fix your calibration: the "Analyze/Analyze Route" command.

After applying the Analyze Route command it's obvious where your position changed.
Screen Shot 2019-08-24 at 3.52.43 PM.png
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I deleted 3 small sections, each about 4 minutes long. You have plenty of data for your training analysis!
Screen Shot 2019-08-24 at 3.56.26 PM.png
Screen Shot 2019-08-24 at 3.56.26 PM.png (167.02 KiB) Viewed 276683 times
Your CdA seems quite low; what is your height, and are you riding on the hoods or perhaps upright?
Attachments
jonao_corr_08_24_2019_1152_27_km.ibr
(411.2 KiB) Downloaded 603 times
jonao.ibp
(503 Bytes) Downloaded 644 times
John Hamann
jonao
Posts: 16
Joined: Fri Jun 28, 2019 10:37 am

Re: high power at road bumps

Post by jonao »

.....2 questions...
1) After importing your cal-file it cannot be sent to the PP, both fric and tilt being out of range.
fric out of range.PNG
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2) I tried correcting the ride as you did, the result looking similar, but my max slope still being at 49%, while yours is 6%. Any idea?
your corrected ride.PNG
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my corrected ride.PNG
my corrected ride.PNG (137.52 KiB) Viewed 276667 times
jonao
Posts: 16
Joined: Fri Jun 28, 2019 10:37 am

Re: high power at road bumps

Post by jonao »

Today I succeeded in having my suspension fixed as far as it can. Now at the road bumps the power seems to behave,
and only at start up it is sill off to the sky.
Would it be of any further help to have the PP not smooth power dynamicallly, but say 2 sec, of even 0 sec?

full ride==>
iBike_08_26_2019_0933_15_km.ibr
(111.25 KiB) Downloaded 611 times
start at 5 minutes ==>
2018-08-26-at 5 min.PNG
2018-08-26-at 5 min.PNG (187.87 KiB) Viewed 276651 times
Velocomp
Velocomp CEO
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Re: high power at road bumps

Post by Velocomp »

jonao wrote: Mon Aug 26, 2019 5:30 am Today I succeeded in having my suspension fixed as far as it can. Now at the road bumps the power seems to behave,
and only at start up it is sill off to the sky.
Would it be of any further help to have the PP not smooth power dynamicallly, but say 2 sec, of even 0 sec?

full ride==> iBike_08_26_2019_0933_15_km.ibr
start at 5 minutes ==>
2018-08-26-at 5 min.PNG
Stick with DPS. It will minimize watts spikes.
John Hamann
jonao
Posts: 16
Joined: Fri Jun 28, 2019 10:37 am

Re: high power at road bumps

Post by jonao »

Alright DPS.

Do you have any suggestions about the not wanting to be PP-loaded .ibp you provided?
jonao
Posts: 16
Joined: Fri Jun 28, 2019 10:37 am

Re: high power at road bumps

Post by jonao »

By the way, reading through our corresponce I hit your remark "Your CdA seems quite low; what is your height, and are you riding on the hoods or perhaps upright?" - and I cannot find my answer, though I am pretty sure I did send feedback. So, here it is again.
Yes my CdA is low, my height =136cm, and I am sitting upright.

I tried fiddling with the CdA value in Isaac, I also rode circuit rounds and extracted the best fitting results from my own Chung virtual-elevation analysis, but when I tried inserting them into the calibration some other parameters had become "out of range".
So I stopped and chose accepting the setting as it was, not caring for absolute Power, but wanting to see how the power develops
between rides.
As long as those sky high bump peaks were there, that failed. But since they are now gone, I have high hopes.

Maybe some day I should repeat an out&go recalibration and start using that.
But I still do not understand how I can first instruct the PP to use, say, CdA=0,6, and not have that value being recalculated during the out&go ride.
If I set it in Isaac to 'fixed' after importing the Out&Go ride, until now I ran into those 'out of range' warnings for other parameters too.

Do you have any idea why the jonao.ibp you provided to me, will not load into my PP but complain about 'out of range' values too?
Velocomp
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Re: high power at road bumps

Post by Velocomp »

Please do a new calibration ride. Your profile is so far out from the norm that an adjusted profile is out of range.
John Hamann
jonao
Posts: 16
Joined: Fri Jun 28, 2019 10:37 am

Re: high power at road bumps

Post by jonao »

did so, in Isaac adapted CdA and Crr as found from my circuit fit, and set in PP.
Wait and see what it will bring.
jonao
Posts: 16
Joined: Fri Jun 28, 2019 10:37 am

Re: high power at road bumps

Post by jonao »

disappointment: In today's new ride, after reading it into Isaac, the values of CdA&Crr are NOT as those exported, but the original values back which I especially had replaced;
todays:
CdA has unwantedly been switched back.PNG
CdA has unwantedly been switched back.PNG (198.67 KiB) Viewed 276504 times
set profile 2 days ago:
settings of 20190828 as sent to device PP.PNG
settings of 20190828 as sent to device PP.PNG (196.17 KiB) Viewed 276504 times
also I received an unknown error 6004 while automatic downloading from PP to Isaac, and only after closing the error message was able to download from the PP.
1. fout melding Isaac.PNG
1. fout melding Isaac.PNG (16.2 KiB) Viewed 276504 times
jonao
Posts: 16
Joined: Fri Jun 28, 2019 10:37 am

Re: high power at road bumps

Post by jonao »

Should I move my latest message to another forum board?
jonao
Posts: 16
Joined: Fri Jun 28, 2019 10:37 am

Re: high power at road bumps

Post by jonao »

SO, how can I change CdA & Crr in the PP and keep those values fixed?
Velocomp
Velocomp CEO
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Joined: Fri Jan 11, 2008 8:43 am

Re: high power at road bumps

Post by Velocomp »

jonao wrote: Tue Sep 03, 2019 11:46 am SO, how can I change CdA & Crr in the PP and keep those values fixed?
1. Go to "Edit/Edit Profiles/Extract Profile from Device" This will transfer the profile that is currently stored by PP

2. Click on the Advanced tab

3. For CdA, click the radio button next to "Wind ScalingAdjust" Adjust will change to Hold, and the radio button next to CdA will change to Adjust

4. Type in the CdA field the number you want to use. You will get a warning message; click OK

5. Repeat the process above to change the Crr number to the number you want

6. Click the "Send to Device" button to store your modified profile in your PP.

7. Click the "Accept" button to save your modified profile in Isaac (you might want to give it a different name)
John Hamann
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