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Calibration Check
Posted: Tue Apr 13, 2021 10:25 am
by Errantwind
I just got my powerpod v4 yesterday I calibrated it this morning on this exact path if you watch it from the start
https://www.youtube.com/watch?v=NuissplxtrU everything looks good but I wanted to double check. Here is a 5 mile ride on the same path from the powerpod after I calibrated. Does everything look good for the road type and bike I am using a check point ALR 5 gravel bike with 700x40c tires, power readings seemed close.
Also is it expected when I burst in power their is a 3-4 sec delay before it shows on screen even tho I am showing raw not 3 sec avg? This is in Wahoo App
- Capture.PNG (31.35 KiB) Viewed 8989 times
Re: Calibration Check
Posted: Tue Apr 13, 2021 10:50 am
by Velocomp
Your calibration is spot-on, but you have a very high Crr (rolling resistance). What kind of bike are you riding, and on what kind of roads?
You have PP set to Dynamic Power Smoothing. That is fine, but you can get faster response by setting it to shorter averaging.
Also, if your bike computer is averaging, that too will delay response time.
Re: Calibration Check
Posted: Tue Apr 13, 2021 11:00 am
by Errantwind
Hard pack gravel and dirt is where I ride its a 50 mile trail and I am using this bike at 35-40psi in the tires. I do use the bike on road sometimes too so I plan to have a sep calibration and profile for those rides.
- 20210321_124500.jpg (387.72 KiB) Viewed 8982 times
Re: Calibration Check
Posted: Tue Apr 13, 2021 12:55 pm
by dmwelk
Velocomp wrote: ↑Tue Apr 13, 2021 10:50 am
Your calibration is spot-on, but you have a very high Crr (rolling resistance). What kind of bike are you riding, and on what kind of roads?
You have PP set to Dynamic Power Smoothing. That is fine, but you can get faster response by setting it to shorter averaging.
Also, if your bike computer is averaging, that too will delay response time.
John, I'm not sure what my power smoothing is set too, but have noticed a little delay in feedback, what setting do you want it on to have a faster response? Sorry to thread hi-jack.
Re: Calibration Check
Posted: Tue Apr 13, 2021 3:51 pm
by Errantwind
Being I am a software test engineer for a living I took the liberty of doing some analysis and research. Seeing from other advice on the forums the only setting I should be playing with to get this accurate after a calibration is the CRR(I did this on the ride files using Analyze->tweak) , which from the auto cal and tire selection wanted 0.0136, this is actually very close to my real power curve when compared to historical zwift rides on a direct drive trainer. when I took a closer look 0.0140 crr appears to be the correct number(Within 3% margin) after doing a 15 mile ride and 2x 5 mile rides today on the path to get data to compare against. This path has less then 1% slope change for the whole duration so its pretty good to get a idea of rolling resistance.
So for all you gravel bike riders riding on hardpack dirt and gravel with 36c or wider tires at around 35-40psi 0.013 crr is a good starting point for that type of riding and for the road I found 0.0085-0.0095 seems to be fairly accurate when compared(Need to do more riding on paved surfaces to get data)
Please let me know if this info seems way off Velocomp so others don't follow it but I think I got it locked in now. I was sort of worried my CRR was so high from reading other stuff but it seems very accurate when I apply the CRR value to a ride I did post ride.
Re: Calibration Check
Posted: Tue Apr 13, 2021 4:19 pm
by dmwelk
Errantwind wrote: ↑Tue Apr 13, 2021 3:51 pm
Being I am a software test engineer for a living I took the liberty of doing some analysis and research. Seeing from other advice on the forums the only setting I should be playing with to get this accurate after a calibration is the CRR(I did this on the ride files using Analyze->tweak) , which from the auto cal and tire selection wanted 0.0136, this is actually very close to my real power curve when compared to historical zwift rides on a direct drive trainer. when I took a closer look 0.0140 crr appears to be the correct number(Within 3% margin) after doing a 15 mile ride and 2x 5 mile rides today on the path to get data to compare against. This path has less then 1% slope change for the whole duration so its pretty good to get a idea of rolling resistance.
So for all you gravel bike riders riding on hardpack dirt and gravel with 36c or wider tires at around 35-40psi 0.013 crr is a good starting point for that type of riding and for the road I found 0.0085-0.0095 seems to be fairly accurate when compared(Need to do more riding on paved surfaces to get data)
Please let me know if this info seems way off Velocomp so others don't follow it but I think I got it locked in now. I was sort of worried my CRR was so high from reading other stuff but it seems very accurate when I apply the CRR value to a ride I did post ride.
Errantwind:
Thanks for the information, I guess I need to go in and setup ride files for both gravel and road. I ride a gravel bike with tubeless specialized 42mm Pathfinder Pro tires set at 44 psi ( rear) and 39 psi (front) on pavement and 40 psi and 35 on gravel. I have been primarily riding pavement, but the weather has been getting nicer in the PNW. A co-worker and I were planning a 60 mile gravel ride this Saturday that we have been wanting to do.
Re: Calibration Check
Posted: Tue Apr 13, 2021 4:53 pm
by Errantwind
dmwelk wrote: ↑Tue Apr 13, 2021 4:19 pm
Errantwind:
Thanks for the information, I guess I need to go in and setup ride files for both gravel and road. I ride a gravel bike with tubeless specialized 42mm Pathfinder Pro tires set at 44 psi ( rear) and 39 psi (front) on pavement and 40 psi and 35 on gravel. I have been primarily riding pavement, but the weather has been getting nicer in the PNW. A co-worker and I were planning a 60 mile gravel ride this Saturday that we have been wanting to do.
I live around the block from 400 miles of accessible gravel pack and paved trails I tend to go on all gravel most of the time but sometimes do both in one ride so I would like to come up with a happy medium profile that works for that but I have a feeling that is a limitation of the device atm, would be nice to be able to hotswap profiles from the powerhouse app (maybe you can but from my understandings its a bit limited). On a multi surface ride I would rather my reading be low then to high and mess up training status so I plan to use my road profile for those rides.
Re: Calibration Check
Posted: Wed Apr 14, 2021 6:25 pm
by Errantwind
Today I did another validation ride. High end tempo about 10-15% less then I can do max. I then compared it against my zwift Power Curve records w/Direct trainer from January and February this year. During todays ride I did a full out 1 minute effort and a full 5 minute effort for what I was capable of. This thing is super locked in when you take the time to understand everything. This was at 1.4crr bumped from 1.36crr that the auto cal gave me on hardpack gravel.
Amazing little device love it!
- Zwift Vs PowerPod similar efforts.PNG (39.56 KiB) Viewed 8944 times
Tech specs:
Trek Check Point ALR 5 Gravel Bike
GR1 Comp Tires 40PSI 700x40c
Hardpack Gravel and Dirt surface (Zero Road)
Custom CRR 1.40 from Auto Calibrated 1.36
PowerPod V4
Re: Calibration Check
Posted: Thu Apr 15, 2021 7:27 am
by Velocomp
Errantwind wrote: ↑Wed Apr 14, 2021 6:25 pm
Today I did another validation ride. High end tempo about 10-15% less then I can do max. I then compared it against my zwift Power Curve records w/Direct trainer from January and February this year. During todays ride I did a full out 1 minute effort and a full 5 minute effort for what I was capable of. This thing is super locked in when you take the time to understand everything. This was at 1.4crr bumped from 1.36crr that the auto cal gave me on hardpack gravel.
Amazing little device love it!
Zwift Vs PowerPod similar efforts.PNG
Tech specs:
Trek Check Point ALR 5 Gravel Bike
GR1 Comp Tires 40PSI 700x40c
Hardpack Gravel and Dirt surface (Zero Road)
Custom CRR 1.40 from Auto Calibrated 1.36
PowerPod V4
What is plotted on the horizontal axis?
Re: Calibration Check
Posted: Thu Apr 15, 2021 9:14 am
by mir
Velocomp wrote: ↑Thu Apr 15, 2021 7:27 am
What is plotted on the horizontal axis?
My guess is that it is watt distribution. Eg. how long time on this particular ride you performed this watt number.
Re: Calibration Check
Posted: Thu Apr 15, 2021 2:04 pm
by Errantwind
Oops I didn't realize I cut off the timeframes let me repost
- Zwift Vs PowerPod similar efforts.PNG (42.26 KiB) Viewed 8894 times
Re: Calibration Check
Posted: Thu Apr 15, 2021 3:52 pm
by Velocomp
Which curve is which device?
Re: Calibration Check
Posted: Thu Apr 15, 2021 4:25 pm
by Errantwind
This ride is powerpod v4, the dark purple. The light purple is my combined historic power curve from Zwift on a direct trainer for the beginning of this year.
Re: Calibration Check
Posted: Fri Apr 16, 2021 11:51 am
by dmwelk
Errantwind wrote: ↑Wed Apr 14, 2021 6:25 pm
Today I did another validation ride. High end tempo about 10-15% less then I can do max. I then compared it against my zwift Power Curve records w/Direct trainer from January and February this year. During todays ride I did a full out 1 minute effort and a full 5 minute effort for what I was capable of. This thing is super locked in when you take the time to understand everything. This was at 1.4crr bumped from 1.36crr that the auto cal gave me on hardpack gravel.
Amazing little device love it!
Zwift Vs PowerPod similar efforts.PNG
Tech specs:
Trek Check Point ALR 5 Gravel Bike
GR1 Comp Tires 40PSI 700x40c
Hardpack Gravel and Dirt surface (Zero Road)
Custom CRR 1.40 from Auto Calibrated 1.36
PowerPod V4
Errantwind:
Are you just manually changing your CRR. I'm not seeing any other road surfaces other than varying asphalt and concrete. Plan on doing a gravel ride tomorrow and would like to setup another file for gravel.
Re: Calibration Check
Posted: Fri Apr 16, 2021 12:50 pm
by Errantwind
dmwelk wrote: ↑Fri Apr 16, 2021 11:51 am
Are you just manually changing your CRR. I'm not seeing any other road surfaces other than varying asphalt and concrete. Plan on doing a gravel ride tomorrow and would like to setup another file for gravel.
I set it manually after calibration, this is the process I used:
(Complete a regular auto calibration on the surface before starting)
1. took a ride with the auto calibration complete,
2. imported that into Isaac,
3. knowing my real power curve in the last 2 months I used that as a baseline to adjust the CRR on the auto calibrated ride until it matched my power efforts I expected for the ride
4. Set the CRR I found in step 3 and sent it to the device profile
5. Went on a hour ride at tempo with 4 targeted windows of effort 2x 1 min max effort and 2x 5 min max effort
6. Imported the hour ride into Isaac and strava
7. Compared the over all ride to what my appeared effort was but more importantly check my 1 and 5 min efforts to see how they matched up with a known power curve.
8. Validated my CRR from step 4 for that type of surface ride
Hope this help.
Re: Calibration Check
Posted: Fri Apr 23, 2021 4:26 pm
by Errantwind
I did a hour long pavement ride today on this same bike to help get a baseline auto cal had it correct selected 0.00851 crr which matched up perfectly with my power curves for the efforts. These test were done with the Bontrager GR1 Team Issue Gravel Tire 700x40c inflated to recommended PSI 45-50.
Re: Calibration Check
Posted: Fri Apr 23, 2021 5:49 pm
by Velocomp
Errantwind wrote: ↑Fri Apr 23, 2021 4:26 pm
I did a hour long pavement ride today on this same bike to help get a baseline auto cal had it correct selected 0.00851 crr which matched up perfectly with my power curves for the efforts. These test were done with the Bontrager GR1 Team Issue Gravel Tire 700x40c inflated to recommended PSI 45-50.
This is very useful information; thanks!