Calibration Check

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SilasGreenback
Posts: 49
Joined: Fri May 22, 2020 11:55 am

Calibration Check

Post by SilasGreenback »

A steady away pootle after mucking around with the tilt at the weekend. Seems a massive change in friction from pre-movement and a substantial drop in power....although i was taking it really easy so could believe it being that low. PLease could you check it out and see if it's OK.

Thanks
John.
Attachments
Velocomp_11_09_2020_0644_18_Miles.ibr
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Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: Calibration Check

Post by Velocomp »

This is a long O&B ride. Assuming that wind conditions did not change, then corrected ride file and profile are attached.

It's pretty close to your unaltered file.
Attachments
Silas_Corr_11_09_2020_0644_18_Miles.ibr
(280.42 KiB) Downloaded 153 times
Silas.ibp
(671 Bytes) Downloaded 138 times
John Hamann
SilasGreenback
Posts: 49
Joined: Fri May 22, 2020 11:55 am

Re: Calibration Check

Post by SilasGreenback »

Superb thanks. Yeah....family dont like to see me “playing out” too much when everyone is supposedly locked down so have to kill as many birds with one stone as I can. All legitimate exercise :)

Wind was consistent throughout so thanks for checking it over.
RoadWarrior
Posts: 20
Joined: Tue Aug 11, 2020 12:12 am

Re: Calibration Check

Post by RoadWarrior »

Since I don't want to open a new thread and this comes close to my point I just use this one here.

I just added a DFPM to the PP and went for a ride today.
After the ride I used the calibration check and I'm a bit baffled:
Image

I use Aerobars (Profile Design Jammer GT)(arm rest is on same height as saddle (Haven't managed to bend more down yet))
and use Continental Grand Prix with 110PSI (7.584 Bar) with a CRR of 0.0043 (https://www.bicyclerollingresistance.co ... -prix-2014)
Given this known value, I assume it shouldn't be changed.

Isaac is not changing CRR, but increases Aero and CdA quite some.
In my understanding a CdA of 0.404 is riding a road bike in upright position.

How is it possible that isaac is applying these changes?

Thanks

Remo
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Velocomp_12_26_2020_1004_25_km_HiDef.ibr
(597.84 KiB) Downloaded 142 times
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: Calibration Check

Post by Velocomp »

In the file you attached, you used the Check Calibration feature. This feature corrected for wind speed that was too low.

However, in the file you attached your Crr is way too high; 0.009. That would be like riding a fat bike.

When Crr goes up, CdA must go down. This is so that power balances. With your high Crr, your CdA is a low value of 0.304

You corrected your CdA, based on a value for your tires of 0.0043. Tires alone do not create rolling resistance, the road surface type is important too. As a simple example, imagine riding your skinny and efficient tires on sand; the Crr rolling resistance would be much higher than 0.0043.

The default rolling resistance value that we use for road bikes, which accounts for both tire type and road surface type, is 0.0054.

When I apply this value of Crr to your ride file and reprocess your Check Calibration, your CdA becomes a very reasonable .380.

Corrected ride file and profile attached.
Attachments
RoadWarrior_12_26_2020_1004_25_km_HiDef.ibr
(597.99 KiB) Downloaded 151 times
Road Warrior.ibp
(1.3 KiB) Downloaded 138 times
John Hamann
RoadWarrior
Posts: 20
Joined: Tue Aug 11, 2020 12:12 am

Re: Calibration Check

Post by RoadWarrior »

Hi John,

yeah, the 0.009 is a value that isaac automatically did choose/offer at some stage during the calibration.

I felt that this is wrong. However, I tried to stick/set the value back to .0043 but apparently it didn't.
Road blend here is mainly chip seal. I also did add this to the calibration, but as it seems it didn't take it.
I will look how I go with your files.

Thank you
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lorduintah
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Joined: Fri Jan 11, 2008 9:37 am
Location: Plymouth, MN

Re: Calibration Check

Post by lorduintah »

For things to stick you must click on the "Accept" button - or it won't.
RoadWarrior
Posts: 20
Joined: Tue Aug 11, 2020 12:12 am

Re: Calibration Check

Post by RoadWarrior »

lorduintah wrote: Sat Dec 26, 2020 3:29 pm For things to stick you must click on the "Accept" button - or it won't.
Hi, Thanks for the advise, though I'm 100% sure I did do that.
But also looking at certain setting options like Surface/tyre grade, any settings I possibly could have changed, none of them gives me a 0.009 output.

so absolutely no idea how this 0.009 came there.
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