Newton Max Power

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JulianBoulter
Posts: 62
Joined: Wed Jan 22, 2014 5:38 pm

Newton Max Power

Post by JulianBoulter »

Tried my new iBike for the first time on the weekend and loving the unit but am seeing something I was not expecting, here is what I did...

I performed the calibration ride and then following did 4 training sessions. When I got home I connected the iBike and the Dial-in wizard kicked in and then I entered bike and rider information to save the profile and then sent it to the ibike. I then used the Tools menu to 'switch profile after the ride' to this newly created profile (as my 4 training sessions were undertaken after the calibration ride but before I modified the profile in Issac) and I saw various data change with the new personal settings. When I examined the data I see the peak power in the graph corresponds with the 811W reported in the panel, so far so good, however then I added 'annotations at peaks', and notice that the 811W peak is in fact 1124W, so I changed the Issac smoothing to 0.00 from 0.05 and sure enough the graph changes to reflect the 1124W...BUT, no matter what I do, the panel on the left only ever shows the 811 watts from the 0.05 smoothing, and even when I select the peak and see that power was 1124W in the bottom of the screen at that point in time, the panel on the left never reflects the actual max.

So I experimented more, and downloaded the rides again this time without the 'auto analyze route' preference set thinking it might help but it made no difference, and even when I look at the CSV data or export to Strava or Garmin everthing reports the 1124W max apart from Issac at 0.00 smoothing.

Interesting though, when I looked at 'switch profile after the ride' again, I can actually see the 1124 max in the dialog box but never in the main Issac window so what am I missing? or is it expected that the left panel will only ever show to 0.05 smoothing??

Pics and ride file attached

Thanks

Julian
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racerfern
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Re: Newton Max Power

Post by racerfern »

Bullet points:
1) Never "Switch Profile After the Ride" unless you happen to be on a completely different profile by mistake. The slight nuances will never give you the exact numbers...really close but not EXACT.
2) Regardless of your smoothing settings the stats window will not display different numbers though I'm not sure what smoothing factor it's based on (probably 5s)
3) Maximum wattages are for all intents and purposes useless. It's just a number that lasted for a very brief period of time. Don't miss the forest for the trees???
4) RE:3, what's the difference? Tell me you can hold either number for 30 seconds and I'll pay attention. I'm not saying that in a snooty way, it's just you need to not chase numbers for the sake of the numbers.
5) I personally do not auto analyze. I am dialed in so that I don't need corrections. I have total faith in the data recorded by Newton. I simply enter starting and ending elevation and remove all other check boxes.
6) Note that exporting to other formats and importing into other programs will produce different results since you don't necessarily know how other software "massages" the data.

Please don't misunderstand comment #4 or for that matter any of the others.
Fernando
JulianBoulter
Posts: 62
Joined: Wed Jan 22, 2014 5:38 pm

Re: Newton Max Power

Post by JulianBoulter »

Hi racefern, thanks for the response, actually I have had quite a long thread going with Tom Gore since I posted this, it seems the panel just defaults to the 5 second smoothing so you will never see anything outside of the 5 second smoothing within the file in the panel data, I just think it would have made more sense to update the panel data if the user changes the smoothing otherwise it just looks odd.

My main question/concern was, being as the software allows me to see recalculated data if I highlight a section (a very powerful feature), if I were to include the hidden sections in the selection, would it take that into account in the calculations or would it ignore it?

Regarding your bullet 1, I didn't see any other way of doing this as I had not entered the user setup routine prior to the calibration ride, so you are saying that when using the unit for the first time you must either enter the user setup routine prior to the calibration ride or do the calibration ride, come home, use Issac to enter the user setup routine, send the profile to the unit, then do your training right? "Switch Profile After the Ride" just seemed to be purpose built for the what I used it for.

Anyway, loving the unit and starting to trust the data I am seeing (as a new user of the product, I am still on the learning curve!)
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Russ
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Joined: Sun Feb 10, 2008 4:08 pm

Re: Newton Max Power

Post by Russ »

JulianBoulter,

You said:
Regarding your bullet 1, I didn't see any other way of doing this as I had not entered the user setup routine prior to the calibration ride, so you are saying that when using the unit for the first time you must either enter the user setup routine prior to the calibration ride or do the calibration ride, come home, use Issac to enter the user setup routine, send the profile to the unit, then do your training right? "Switch Profile After the Ride" just seemed to be purpose built for the what I used it for.

My thoughts:
I have done essentially that too. I was not looking especially for the of peak power but only trying to improve the overall accuracy of that ride.

My personnel impression is that you probably did improve the overall accuracy but I can't argue with Racefern's point either regarding absolute accuracy. So if you demand that for the ride following the cal ride, yes I think you should return to the computer first. However, after my initial cal ride, I repeat the out and back part as a ride immediately after the cal ride and use that in Isaac for an initial check and tweek of my resulting profile, I think I recall Racefern having suggested that method in the past.

Just my two cents worth. Oh and impressive power either way, I only hit 1100 watts near the end of a time of doing Tabata hi intensity training for a few weeks and when I stopped that went away :-)

Regards,
Russ
JulianBoulter
Posts: 62
Joined: Wed Jan 22, 2014 5:38 pm

Re: Newton Max Power

Post by JulianBoulter »

Thanks Russ,

Yes I think riding out and back following the calibration ride is a good tip and I will try that next time. I have a couple more questions/observations

1) Am thinking that using an out and back ride as a base line to determine / confirm the wind scaling factor is always likely to introduce a small variation between out and back as the wind is not constant, I guess that's why light winds are recommended for the calibration ride but I can't see that achieving an exact matching average for speed and wind should ever be truly possible unless the wind is constant ?

2) I'm taking the data in Issac as gospel at 0 smoothing, what I'm doing for each ride now is applying annotations at peaks to reveal the hidden peaks and I have the iBike set to 0 second smoothing too, however, after rides I notice that if I choose to view max power on the iBike, it never matches what I see in Issac at any smoothing. For example, on a ride I did over the weekend the max power displayed on the iBike itself for the ride is 1038W, whereas in Issac, it is showing me 888W max at 5 second smoothing and 1136W max at 0 second smoothing, I see small differences in NP between the iBike unit and Issac too. As I said, I am trusting the Issac data at 0 smoothing to be the true picture but when I start peak power testing, ideally I want to see the same figure on the iBike. I noticed my firmware revision is 2.09 so a little out of date but didn't see anything in the revision notes to indicate this has been addressed in a later revision

BTW, I just noticed that fast recording was set to on so I have switched if off as I do not have PowerStroke but from what I have read, having fast recording on should append Hi-Def to all of my ride files which is not the case
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racerfern
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Re: Newton Max Power

Post by racerfern »

AFA #1, wind is a constant varying force that will almost never equal zero for an out/back ride especially when not under controlled conditions. My "average" ride almost always has about -1.2mph avg wind because of all the traffic whizzing by. At first I wondered if my profile was off so I would go and do another cal ride but ended up with the same profile. When I do a cal ride which is not even once a year, I personally do them on a paved river trail section at an ungodly hour of the morning to avoid other cyclists/pedestrians and to take advantage of nearly calm wind conditions. The less wind for a cal ride, the better.

AFA #2, note that even the display on Newton has a refresh rate. It's entirely possible that the 1136w occurred at an instant when the display was refreshing. In fact, it's likely. But I go back to my previous comment about the importance of max power. IMO the interest needs to lie in max power for a given amount of time, be it 10 seconds all out, 10 seconds easy, 10 seconds all out... or even 1 minute intervals. I don't see any advantage to knowing the max power for a brief instant over the course of a ride. Over the course of a training period you should see your max power increase as you get stronger but even that can vary day to day depending on your fitness, health, stress, etc.

BTW, Russ makes a great point with the suggestion to do an out/back ride on exactly the same course as a cal ride. Doing it immediately after the cal ride will give you confirmation of a good cal ride.

FYI, my Newton OS is 4.13 and Isaac is 2.3.0, check yours.
Fernando
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