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Best accuracy of Newton+ (DPFM is present)

Posted: Tue Aug 28, 2018 3:11 am
by Zoltan
Hi John,

To be honest I had forgotten a lot about the calibration of Newton(+) and therefore yesterday I read the Newton manual. Since now I use FW4.16 as a consequence of your kindness (see viewtopic.php?f=84&t=4596) I read both the manual for Newton with 4.x and that for Newton with FW5.x. I mean I have the option to switch between FW4.13 and 5.18 back and forth at any time.

I also read the Cda instructions since I have a Newton+ and I also have a DFPM.

So I have a DFPM equipped recumbent bike and finally I could mount my Newton in a proper way fabricating a special mount for me. Now I want the best accuracy. I decided to keep in mind that I can calibrate my bike either with FW4.16 or FW 5.18. Do I understand the following well?

1. Even if the manual for FW5.x writes about the simplified cal ride of 5 mins (no out and back required) as a simplified cal ride, it just gives the same Good accuracy for my Newton FW 5.x as it would have been done with a Newton FW4.x?

2. If I use the 10 mins cal ride with my Newton 5.x it gives me the same best accuracy as if the calibration would have been done with my Newton 4.x if I make the same, necessary steps in Isaac (like giving my data through Device Setup)?

3. This is my most important question: if I have a DFPM which is used during my 10 mins cal ride, it makes no difference what position I specify for the dial in like hood, TT etc, since DFPM data will override any of my data except maybe my weight?

Re: Best accuracy of Newton+ (DPFM is present)

Posted: Tue Aug 28, 2018 8:21 am
by Velocomp
1. No matter which FW you are using, you should do a full, best-accuracy out-and-back cal ride. This will work best for your DFPM.

2. Correct

3. If you use the "Check Calibration" feature and use the DFPM data, you are correct that the CdA calculated by Isaac will override the default value determined by hoods/TT etc.

Re: Best accuracy of Newton+ (DPFM is present)

Posted: Tue Aug 28, 2018 8:35 am
by Zoltan
Re 3: is it true for Crr, too?

In other words: do coastdowns add anything to the accuracy of Crr vs the best accuracy method made by out and back ride corrected by Check Calibration?

Re: Best accuracy of Newton+ (DPFM is present)

Posted: Tue Aug 28, 2018 9:36 am
by Velocomp
Coast downs do not function in recent releases of FW.

Re: Best accuracy of Newton+ (DPFM is present)

Posted: Tue Aug 28, 2018 10:22 am
by Zoltan
I meant in 4.16 coastdowns is still there. EDIT: But it seems that it still there in Newton FW 5.x, too, just see the latest manual of Newton.

3/a Anyway does Check Calibration with DPFM override Crr number, too, doesnt it?

3/b what is your experience? Does DPFM or coastdowns add better accuracy?

I know that a properly done Coastdowns can be better than the so called Good accuracy, but whether it can better than a CRR calculated from both Newton cal ride and DPFM data?

Re: Best accuracy of Newton+ (DPFM is present)

Posted: Tue Aug 28, 2018 3:27 pm
by Zoltan
I spent at least one and a half hour searching for it, but finally I seem to have the answer: viewtopic.php?t=1347#p7404

Re: Best accuracy of Newton+ (DPFM is present)

Posted: Tue Aug 28, 2018 5:28 pm
by Zoltan
But I dug more into the manual of Isaac and by now I changed my hypothesis. Since in Check Calibration with DFPM has only two tabs under Crr vs Cda where there are 3 tabs including DFPM fit, and these 2 tabs are Original and Estimated, and under Estimated Crr one HAS TO choose the road surface, the type of the tyre, the tyre grade and the tyre pressure I feel that DFPM data has NO effect on Crr, just on Cda. And therefore if one still uses a FW earlier than 5.0 it might make sense to use coast downs.

If Crr came from the DFPM data then a separation of the effect of rolling resistance and that of wind could be done without specifying anything related to the tyre, couldnt it?

See John, I really put lots of effort to fully understand the different options of calibrating.

Can you please confirm or deny my bolded conclusion above?

Re: Best accuracy of Newton+ (DPFM is present)

Posted: Thu Aug 30, 2018 9:53 am
by Zoltan
Velocomp wrote:
Tue Aug 28, 2018 9:36 am
Coast downs do not function in recent releases of FW.
I checked the release notes of Newton firmware and found no reference that Coast downs have been eliminated.
I also checked the Newton manual 5.x and higher and Coast Downs is stil lthere as a menu item of Newton.

Since I am now on 4.16 due to the need of Lcd Contrast function, I cannot check it, but Coast Downs must be there on 5.18, too.
Are you fully sure, John, that you eliminated Coast Downs? Is it not just the case that you do not propose it any longer.

Re: Best accuracy of Newton+ (DPFM is present)

Posted: Thu Aug 30, 2018 12:12 pm
by Velocomp
I don't know if the feature was officially deleted, but we do not support this any longer. It's not that it does not work; rather, it is a complicated measurement that is difficult to do successfully.

Re: Best accuracy of Newton+ (DPFM is present)

Posted: Fri Aug 31, 2018 9:26 am
by Zoltan
Zoltan wrote:
Tue Aug 28, 2018 5:28 pm
But I dug more into the manual of Isaac and by now I changed my hypothesis. Since in Check Calibration with DFPM has only two tabs under Crr vs Cda where there are 3 tabs including DFPM fit, and these 2 tabs are Original and Estimated, and under Estimated Crr one HAS TO choose the road surface, the type of the tyre, the tyre grade and the tyre pressure I feel that DFPM data has NO effect on Crr, just on Cda. And therefore if one still uses a FW earlier than 5.0 it might make sense to use coast downs.

If Crr came from the DFPM data then a separation of the effect of rolling resistance and that of wind could be done without specifying anything related to the tyre, couldnt it?

See John, I really put lots of effort to fully understand the different options of calibrating.

Can you please confirm or deny my bolded conclusion above?
I solved my dilemma without using Newton, a good source of Crr is here https://www.bicyclerollingresistance.co ... ourse-2014