What % of assist is everyone using?

Mikerb

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All the software controlling the motor output can do is regulate the amps it draws from the battery. The pedal assist % setting is designed to make access to motor assistance easy ie with least rider input. It is therefore clearly not linked in a linear fashion to torque input from the rider. From a stand still the rider torque would be a lot and decrease as the bike overcomes inertia and gains momentum and motor support in your examples would then decrease. Wheras the max setting puts a cap on the total amperage the motor is allowed to draw (which in turm is a % of total motor power capability) the pedal assist setting is the percentage of total motor power easilly accessible ......controlled by a combination of inputs from the torque speed and cadence sensors. Only the software programmers know exactly how those algorithms are configured but they are clearly quite complex.
So I believe the mode settings % relate to total motor power as controlled by amps drawn not directly to % of rider torque input.
 

TheBikePilot

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For sure, I’ll bet there’s a bit more to it than that. The Brose motor was the most natural feeling of the offerings at the time and Brose let Specialized use the firmware source code to develop their own app and ‘tuning’ and stood by the warranty on the motors.

In essence what I’m saying is that’s how the assistance settings determine the motor output, by way of amps drawn ?
 

Mikerb

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For sure, I’ll bet there’s a bit more to it than that. The Brose motor was the most natural feeling of the offerings at the time and Brose let Specialized use the firmware source code to develop their own app and ‘tuning’ and stood by the warranty on the motors.

In essence what I’m saying is that’s how the assistance settings determine the motor output, by way of amps drawn ?
Yes but the mode settings percentages are percentages of total engine power not rider input.
I also do not believe shuttle merely switches modes to 100% or indeed at all. What it most certainly does is to treat cadence as the main determinent of power delivery rather than torque. That would be however easilly tested. If you are right the level of assist at a given cadence would be the same once shuttle is implemented regardless which mode is selected. I have never found a need to use it so I dont know....maybe someone could do some tests.
 

TheBikePilot

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My understanding is it gives 100% of the peak power set for that mode regardless of rider input so in effect you just need to touch the pedals round. Designed to shuttle you back up a hill at a bike park.

The torque settings etc I used as an example to get my head around the physics. It makes it a bit easier for me to understand what the settings are trying to achieve.

I haven’t fiddled with shuttle but, again my understanding and I could well be wrong, that really it was on or off as in a previous incarnation I could only set it to 0/100 but mine is allowing other settings!
 

coggbike

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My understanding is it gives 100% of the peak power set for that mode regardless of rider input so in effect you just need to touch the pedals round. Designed to shuttle you back up a hill at a bike park.

The torque settings etc I used as an example to get my head around the physics. It makes it a bit easier for me to understand what the settings are trying to achieve.

I haven’t fiddled with shuttle but, again my understanding and I could well be wrong, that really it was on or off as in a previous incarnation I could only set it to 0/100 but mine is allowing other settings!

I believe I read in Specialized literature somewhere (the manual?) that shuttle works at a cadence of 50 and above.

My shuttle adjusts from 0-100% in 20% increments.
 

coggbike

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I believe I read in Specialized literature somewhere (the manual?) that shuttle works at a cadence of 50 and above.

My shuttle adjusts from 0-100% in 20% increments.

Found it. ........cadences above 50.......
ED8311A6-9FB5-45C1-A5A0-860F31D9AC35.jpeg

But noticed it also says it helps “when starting from a standstill”.
 

Mikerb

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As I have said before these are sophisticated algorithms set within a program in the processor and each setting changes the balance of sensor settings in order to regulate motor power. The program was written by analysing ride scenarios including what happens from a standstill or very low speed right through to the max speed cut off. In every mode more power would be made available when the bike speed is very low. Applying a setting greater than zero in both acceleration and shuttle would make that even more noticeable.
 

Mikerb

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Both in the manual and elsewhere Specialized are pretty tight lipped about the way in the various settings available in MC actually work...……..with good reason. The software that controls the motor output is very valuable intellectual property and represents a huge investment in both time and expertise. So they restrict themselves to basic explanations of functionality leaving us all to guess how it actually all works, and then experiment to achieve the sort of motor support each of us find good for our type of riding and needs.
Something of an insight into those software algorithms is the fact that , it is perfectly possible to ride most terrain with very little rider torque and yet no loss of speed. It requires the right gear/cadence/mode and sensible pedal assist/max settings (and that is with acceleration and shuttle both set to zero) . No speed loss, yet neither the motor or drivetrain are stressed and battery consumption is also low. Under those conditions the motor is all but silent reflecting the fact it is acting efficiently.
 

TMS

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Let's keep the maths easy. So let's say the motor is capable of 100nm. Let's work with just one setting as all Eco/Trail/Turbo is/are just motor settings or individual numbers given to Eco/Trail/Turbo rather like the memory seats in your car, just they have a name rather than a number. Your TURBO could be 15%/15% for example. I've worked several worked examples below which are just variations on the numbers. I hope it makes sense..Don't get to carried away with the actual numbers in terms of accuracy, I use them to make a point.

We have two settings in this example and that are primarily tunable in the app and most people ask about:

1. Assist
2. Peak Power

So with your Eco at say: 20%/ 20%. So that's 20% Assist. 20% Peak Power

Rider puts a force in at the pedal of 100nm.
1. Assist is 20% of 100nm (your strong legs pushing the pedals!) = Bike wants to assist 20nm
2. Peak Power is 20% of 100nm (max motor output) = Peak Power available to give you or maximum the motor will help you at the setting dialed is 20nm

All in all 120nm of torque.

All good?

Rider puts in at the pedal 200nm
1. 20% of 200nm = 40nm requested but now limited by bikes peak power of the max output of the motor from our settings, despite being capable of more..
2. 20% of 100nm = 20nm from the motor.

Total rider plus bike 220nm.

Still with me? You increased your output but the bike only gave you the max output you set it, despite being capable of more.

Lets bump up the Peak Power, keep the assist the same.

Assist remain at 20% Peak power at 50%

Take example 1.

Rider puts in at the pedal 100nm.
1. 20% of 100nm = Bike requests assist 20nm
2. 50% of 100nm (max motor output) = Bike can give you 50, but 20% assist is 20.

All in all 120nm of torque. Same output as before, just capable when needed of more if you up the torque..

Example 2.

Rider puts in more effort this time.

Rider puts in at the pedal 200nm
1. 20% of 200nm = 40nm request to the motor.
2. 50% of 100nm (max output available is 50 nm) = 50nm from the motor.

Total rider plus bike 250nm.

Now let us change it to 50% Assist /50% Peak Power

Example 1.

Rider puts in at the pedal 100nm as our first example.
1. 50% of 100nm = Bike assist request to the motor 50nm
2. 50% of 100nm (max motor output) = Peak Power available to give you or maximum the motor will help you is 50nm.

Output 150Nm rider & bike. With me?

Example 2.

Rider goes for it again and puts in at the pedal 200nm
1. 50% of 200nm = 100nm request from the motor.
2. 50% of 100nm (max output) = 50nm from the motor.

Total rider plus bike 250nm.

I hope you can see it's very much a tune, as to how you want the input pedal force to motor response.

So Assist is what the motor will possibly kick you with up the bum with from your input torque, up to a maximum of the peak power, which is how much you've let it.

You can have it push you along more or assist you more but Assist vs Peak power is important in terms of the feel of the bike. A low Assist but high peak power will mean if your really pushing hard the bike will keep giving you power etc.

Acceleration essentially is how fast the motor delivers this power, in race situations or when you want fast pickup this is desirable but there is also motor overrun which is not ideal and makes the bike feel unnatural..

Shuttle essentially bypasses the assist level or rider input torque meaning you just get whatever the peak power setting is for that level you have selected. It's 0 or 100% and is the same across all three modes so it's on or off...Annoyingly you have to get the app out to trigger this..Don't forget to switch it off..!! You just need to turn the pedals so it effectively does not measure the input torque.

The S button defo is not a shuttle setting much as I wish it was or it would be better to have that as a 100/100 whatever your settings are but alas it's not available in the motor firmware apparently.

Hope this helps..

I assume this example was Levo specific. So we need to know which motor? If we assume that the motor is 2.1 S then the maximum assistance level is 410 %. I think you forgot this from your examples.

So when your assistance and peak power levels are set to 100 % you need only 100 % / 4,1 torque from your legs to reach the maximum motor torque. So that would be more like 24 Nm, not 100 Nm like your examples are saying.

And second I prefer that we should use watts not newton meters in this example. You don't need to be strong or fit to make some force/torque to the cranks. All you need to do is to stand on a pedal. And if you're fat it helps. No cadence needed. Of course in this case no work is done either and the power is zero.
 

TheBikePilot

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As I say the numbers/units aren’t important it’s to get a general idea of what the settings doing rather than specifically the output or input unit. It’s hopefully to demonstrate what the settings are..
 

TMS

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As I say the numbers/units aren’t important it’s to get a general idea of what the settings doing rather than specifically the output or input unit. It’s hopefully to demonstrate what the settings are..

My opinion is that your examples are misleading. Because of wrong formula and unrealistic rider torque.
 

Rusty

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And second I prefer that we should use watts not newton meters in this example.
It doesn't really matter what you prefer - Tourque is not measured in Watts.

Torque = Force × Distance.
Force is measured in newton and the distance is measured in meters ... Torque will be measured in newton . meter.
 

YrianX

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It doesn't really matter what you prefer - Tourque is not measured in Watts.

Torque = Force × Distance.
Force is measured in newton and the distance is measured in meters ... Torque will be measured in newton . meter.

Or foot/pounds - ft/lbs?
 

TMS

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I was saying that If you like to present general idea of assistant you should use power not torque in these examples. I can understand/estimate what my power level is when I am pedalling with 90 cadence. No idea what the torque is on that moment. Sure I understand watts and newtonmeters.
 

YrianX

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Change it to whatever unit you feel comfy with man ?

I probably used the wrong unit! Everything was for mental illustrative purposes ?

For what it's worth, I found your calculation / example helpfull and good regardless of units, pretty clear and understandable to me...
 

YrianX

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Thought the world had moved on from that :unsure:

Then again, I still talk Inches. Feet, Yards, Miles - MPH more often than not :whistle:

Yeah I would hope so... I'm Metric to the core baby. Though for some reason we still use ft in aviation. Go figure...
 

Zimmerframe

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Though for some reason we still use ft in aviation. Go figure

That's obvious .. when you're crashing to the ground, out of control, with no wings, blades, hope in hell ... there's more than three times as many feet below you as meters - so it's a bigger number, psychologically making you calmer and giving you more time to come up with a solution ! If they do make the change to metric, height will be measure in cm's or mm's ... We are presently cruising at 146 million 304 hundred thousand millimetres, please enjoy your flight ..
 

YrianX

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That's obvious .. when you're crashing to the ground, out of control, with no wings, blades, hope in hell ... there's more than three times as many feet below you as meters - so it's a bigger number, psychologically making you calmer and giving you more time to come up with a solution ! If they do make the change to metric, height will be measure in cm's or mm's ... We are presently cruising at 146 million 304 hundred thousand millimeters, please enjoy your flight ..

Yeah, just look at Russia that actually works their aviation system in the metrics... Though meters not millimeters (They might have delusions of grandeur over there but not THAT grand ;) ).

Also apparently makes it hell for foreign pilots to fly in there... especially with older non-glass equipped planes
 

Zimmerframe

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Also apparently makes it hell for foreign pilots to fly in there... especially with older non-glass equipped planes

You're not wrong, flying a Sopwith Camel when you don't even have windows, not even the wind down type like they have on low budget airlines ... it's hell ! ;)
 

YrianX

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Yeah, makes sense... Most Sopwith pilots are in the grave where the Macs belong too... The ones still around tends to be of the nostalgic persuasion, so old-fashioned simple computer systems make sense in that case to I suppose ;)
 

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