AAAC 76C
Large Member
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- LIVING THE DREAM
I do not think that speed is calculated by BKool other than that it is, I beleive, the circumferencial velocity of the turbo roller calculated by magnetic interupters similar to a cadence meter. There are 4 magnets on the turbo flywheel which obviously pass by a sensor and create a 4 per rev signal. I have confrimed this when was playing with my turbo the other day when I installed the flywheel back to front and no speed output was displayed. Form this 4 per rev signal and the known circumferance of the turbo roller your speed will be very acurate regardless of wheel diameters or anything else. The only ting that could go wrong is to get the calculation or the SW output wrong but that is so simplistic I very much doubt it.
So this is what I think happens but there is a bit of chicken and egg in this.
The Session course in on you PC and it comminicates with your trainer by giving it such information as weight, windspeed (relative to your heading), road surface drag (remember those sandy coloured bits that sap your strength) and slope.
You start moving and your turbo generates a speed signal from actual speed and tells the PC how fast you are moving.
From this the PC knows where you are on the course and transmits the revised relative windspeed, road surface and slope to your turbo (lets call these the conditions).
Whilst this is all going on your turbo is using the conditions data to set the required resistance for the conditions and your speed. This cycle continues at what ever the 'refresh rate' is and having watched the magnets move whilst messing with my turbo it is pretty instantanious.
I therefore summise that the one true thing you are seeing on the screen is your speed and the watts is a pure calculation but should be directly propotional to the resistance set and your speed. The watts reading is probably generated by the Trainer firmware and not your PC but like trainers should give like watts for the same conditions (see further down for the explaniation of the conditions).
As the BKool firmware has moved on they have changed the way the turbo reacts to the conditions signal sent by the PC and in particular the rate at which the resistance is changed as a result of slope change and for sure the later firmware, which I cannot get because of a PCB fault, delays the onset of the slope resistance more than it was before giving that Pro-Slingshot. This is supposed to replicate your inertia but I think they have got it wrong.
Regarding descending, as we have no motor to drive the back wheel at the descent speed relative to the conditions plus the acceleration due to gravity, they calculated your descending speed which as many has said turns the speed blue. When the speed is blue then the speed is no longer an actual representation of the speed of your turbo roller and so, I for one, can pedal at a reasonably low cadence relative to my ground speed and still lay down some power however as suggested until your actual turbo speed exceeds the blue value the speed figures stay blue.
Now for some theory.
Regarding the sprint, rest, sprint method:
It is possible that either the delay in the reaction of the increase in resistance by both the movement of the magnets and the build up of the eddy currents to induce the drag you can gain speed quicker than you should and thus cover more distance in a shorter time for your effort.
There is also a possibility that the built in lag in the firmware to make transitions more 'lifelike' also retard the rate of the onset of resistance thus adding to your ability to accelerate faster than you should thus again covering more distance in given time.
If however the reduction in restistance is more instantaneous then you would not loose the afore mentioned advantage in your 'rest' phase and the lower you drop your speed in this phase the longer the lag of the build up of resistance on your subsequent acceleration phase therefore you are able obtain an unreal 'advantage' using this method and hence the lower average watts. If during this phase your deceleration is also falsely reduced then further advantage is gained.
I say unreal because it is fact that the most efficent way to get from A to B on a constant slope, be it flat or steep, is with a constant effort. Please don't ask me to explain why this is because I have forgotten the physics but it is probably due to the law that governs the effort required to accelerate a rotating mass has a square in it blah blah blah.
In real life this does not work 100% when the conditions vary but it remains close enough to generalise.
I have no bones with anyone who may be unwitingly using this method as I personnaly am not built to do this and it totally blows me out constantly changing as I am more of a Wiggins than a Contador all be not quite at thier level in anything (and particular in income). I am also sure that this constant variation in output is a really good workout which is why we are doing this in the first place, is it not!
Win or lose I am thouroghly enjoying the competion but if you want reality then there is no better way of getting that than 'reality' as opposed to virtual.
However I would prefer it if we were all a bit more 'matched' in how our trainers react regardless of any minor deviations in our abiliity to generate speed for the same effort.
But as a buisness BKool may need to be on thier guard if there is a growing trend for folks to migrate to the likes of Zwift and in doing so open up the opportunity for individuals to replace thier trainers with other Suppliers products.
If everyone on this forum and hence the current BKool groups went across to Zwift I would probably follow suite and to do so, as I cannot upgrade the firmware on my Classic, I may well look at another product other than one of BKools in order to enable this.
PS: Roll on Saturday' Chaingang as I have decided that as the last league was won on 15 seconds I cannot afford to give away 1 min 30.
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