Electric Assist vs Pedal Assist

General Discussion about electric bicycles.
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DrkAngel   10 GW

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Electric Assist vs Pedal Assist

Post by DrkAngel » Jan 27 2013 9:50am

Yes, there is a difference!
"Electric assist" means that primary and continuous pedaling would be the norm, with occasional, or minimal, motor assist being applied.
"Pedal assist" indicates that the primary and constant force would be the motor, with occasional, or minimal human power assist being added.

Electric Assist
Ideally this would be for a cyclist requiring some degree of assist for greater speed, range ... possibly, merely to help on hills.
This type would be best served with a,
geared hub motor or
a freewheel attached external drive motor or
a (choke!) friction drive motor.

Pedal Assist
More popular with commuters, restricted capability types, etc.
Designed to continuously use motor power, but capable of better acceleration, extending range and speed by applying pedal assist.
This is a perfect fit for the typical hub motor, efficient, quiet and smooth (it's "drag" when not powered is a detriment that does not come into play).

I was confronted with this difference - dilemma when asked to rebuild adult trikes as mobility devices.
Actually, I was considering 3 possibilities.
1. Motor Only - allowing lowered seat, foot platform, gear reduction motor deceleration, reverse mode
2. Motor Assist - Allowing good exercise and mobility with motor capability for greater speed and range while providing the safety net of motor only capability when fatigued.
3. Pedal Assist - gear reduction motor deceleration, reverse mode, with human power assist for hills, speed, range, exercise.
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rocwandrer   100 W

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Re: Electric Assist vs Pedal Assist

Post by rocwandrer » Jan 28 2013 4:16pm

This is an important distinction. Around here, misunderstanding about the goals one way or the other leads to a lot of genuine effort, wasted, giving advice that doesn't apply.
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Toorbough ULL-Zeveigh   10 MW

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Re: Electric Assist vs Pedal Assist

Post by Toorbough ULL-Zeveigh » Jan 28 2013 8:59pm

DrkAngel wrote:Yes, there is a difference!
the difference is about as vast as the glass that's half full or half empty.
there is only power-assist which very effectively covers the continuously variable spectrum from zero to full bore, tyvm.

the phrase 'pedal assist' belongs to the noobinz.
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Kepler   1 GW

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Re: Electric Assist vs Pedal Assist

Post by Kepler » Jan 28 2013 9:34pm

I agree with DrkAngel, there is a difference and IMO the difference distinct.

Point in case:
My Fighter with a PAS sensor and plenty of power falls into the Pedal Assist bracket. What you end up contributing with human power is very minimal as a percentage.

On the other hand my new light weight commuter again with PAS but this time a low powered friction drive falls well and truly in the bracket of Electric Assist with the majority of propulsion provided by the rider rather then the drive.

BTW, don't write off the friction drive. A well executed example can be a very effective and efficient method of propulsion. :wink:
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Toorbough ULL-Zeveigh   10 MW

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Re: Electric Assist vs Pedal Assist

Post by Toorbough ULL-Zeveigh » Jan 28 2013 9:56pm

Kepler wrote:I agree with DrkAngel, there is a difference and IMO the difference distinct.

Point in case:
My Fighter with a PAS sensor and plenty of power falls into the Pedal Assist bracket. What you end up contributing with human power is very minimal as a percentage.
see that's where using two differing terms to describe the same scenario only leads to confusion.
mininal human input would more accurately be called pedal non-assist (therefore power assist) yet you insist on calling it pedal-assist :?

glass half full.

Kepler wrote:BTW, don't write off the friction drive. A well executed example can be a very effective and efficient method of propulsion. :wink:
so effective you felt the need to get a stealth fighter. :wink:
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Sunder   100 MW

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Re: Electric Assist vs Pedal Assist

Post by Sunder » Jan 28 2013 10:07pm

All distinctions are fairly arbitrary, but they are important.

Most people here want an electric motorcycle - something that can go 50km/h+ without any pedaling - something beyond the realm of what even a fit cyclist could do.

Unfortunately, the law in most places excludes electric motorcycles, and is only interested in making a bicycle like experience available for those who are less fit - hence low power limits and speed cutoffs.

This is why there is so much griping about the law here - different goals, so one group thinks that the other has no real experience with electric bikes to set limits so low, and the other group thinks that there are a lot of yahoo law breaking bike riders.
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Kepler   1 GW

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Re: Electric Assist vs Pedal Assist

Post by Kepler » Jan 28 2013 10:13pm

see that's where using two differing terms to describe the same scenario only leads to confusion.
mininal human input would more accurately be called pedal non-assist (therefore power assist) yet you insist on calling it pedal-assist
Seem logical to me. Pedal assist indicates you do the assisting the electrics with the pedals. Electric assist indicates the electrics as there for assistance only.
so effective you felt the need to get a stealth fighter.
That little dig would be more effective if I was going from friction drive to Stealth Fighter as apposed to the other way around. :P of course the Stealth Fighter is the weapon of choice however a fighter doesn't tend to play nicely with general bike path community as apposed to my new build which will hardly get a second look. :mrgreen:
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rocwandrer   100 W

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Re: Electric Assist vs Pedal Assist

Post by rocwandrer » Jan 28 2013 10:26pm

The point, in my view at least, is to have unambiguous language. My thought is that the division point is this: if less than half the total power to the ground is human power, the human assists the motor. And vice versa. Maybe that is all wrong. Maybe its more about intent? The reason it isn't semantics is intent, and the difference in execution that a difference in intent implies. Why the heck would I file the shunt on a ku63? Clearly advice for a sensible person who just wants to get to work as quickly as practically possible isn't right for me, right?
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Re: Electric Assist vs Pedal Assist

Post by Diamondback » Jan 29 2013 8:58am

i consider my trike as well and truly in the electric assist category.

an example, last weekend i did a 47k ride, used only 2.8wh/km.
used 131 watt hours of electricity, and 372 watt hours from my legs.
also, i averaged 154 watts from my legs....

my trike has the V3 CA and Thun installed and setup in PAS mode.

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