Rolling Resistance

[jimmycash245]

Hello,

Could not find the answer on the web I thought, let’s try this forum for my query
The Direct drive hub motor vs. geared hub motor debate.
Rolling resistance on direct drive rear hub motor goes like this.
Valve stem at bottom grab spoke at 90 degrees spin wheel to rear seat stay let go
2.25 rotations on direct drive Rear Hub Motor. my pedal bike can do 7 rotations on rear wheel with this technique.
So, a little rolling resistance but not bad
Does anybody have a geared Rear hub motor e Bike that could tell me what kind of rotation you can get from a geared rear hub motor?
Thanks

 

[ElHegpah]

I see you do research about as well as "scientific testing"

There is no debate.

Geared hubs spin almost, but not quite, as freely as an unpowered wheel.

Direct drive hubs suffer from significant cogging torque caused by the nature of their design. They can operate as a generator, which is what enables regen braking.

The amount of drag for both will vary with particular makes and models, no difference front or rear.

It is possible to feed a DD motor a very small amount of power to just barely overcome the drag.

 

[jimmycash245]

Thanks, with the planetary design it look's like it would isolates itself from that "generator effect".
on a the quest for the right balance of power and watts per mile. for weight reduction.
thanks again.

 

[Django]

The term “rolling resistance” is improper here. You may want to rename the thread.

 

[ElHegpah]

It's not the gears, it's the clutch. Disengages the motor.

IMO, "rolling resistance" does in fact apply although not in the most common form.

 

[Django]

It's not the gears, it's the clutch. Disengages the motor.

IMO, "rolling resistance" does in fact apply although not in the most common form.

Mechanical resistance occurs in the drivetrain. Rolling resistance is in regard to the interface between vehicle and the surface that it is traveling on, (typically tires). Rolling resistance is literally caused from “rolling”. Using the correct terms is important if you want on topic answers.

Understanding Rolling Resistance | TrainingPeaks

Here’s your guide to understanding the often overlooked force component of rolling resistance, and how minor changes might make a difference on race day.

www.trainingpeaks.com

 

[ElHegpah]

If you are not rolling, the resistance does not occur.

The axle/hub interface on a standard bicycle is a factor in "rolling resistance"

The gears in a hub motor are in the same relation. The clutch substitutes for this interface.

In a DD hub, the actual "resistance" is not in the hub/axle interface, but is exerted there.

Interesting question where EXACTLY that resistance exists.

Note to management - There are too many freakin colors when you type with too much bourbon.

 

[Django]

If you are not rolling, the resistance does not occur.

The axle/hub interface on a standard bicycle is a factor in "rolling resistance"

The gears in a hub motor are in the same relation. The clutch substitutes for this interface.

In a DD hub, the actual "resistance" is not in the hub/axle interface, but is exerted there.

Interesting question where EXACTLY that resistance exists.

Note to management - There are too many freakin colors when you type with too much bourbon.

I’ll leave this for others to deal with.

 

[jimmycash245]

Thank you for all the comments
The rolling resistance query is for the Hub Motor Only I am sorry for the confusion maybe I can paint a better picture. Imagine the wheel with inflated tire mounted. Installed on a wheel stand Performing the wheel spin test using the parameters. what is your count. Just lifting the rear wheel off the ground would be sufficient. my test was performed with Peddle bike mounted to a bike stand and DD hub motor e-Bike leaned over on kickstand.

 

[Django]

Thank you for all the comments
The rolling resistance query is for the Hub Motor Only I am sorry for the confusion maybe I can paint a better picture. Imagine the wheel with inflated tire mounted. Installed on a wheel stand Performing the wheel spin test using the parameters. what is your count. Just lifting the rear wheel off the ground would be sufficient. my test was performed with Peddle bike mounted to a bike stand and DD hub motor e-Bike leaned over on kickstand.

I understand the premise. My comment was based on terminology. You really want to know if there is additional resistance in your drivetrain. The wheel freewheeling less does indicate additional resistance, but there are a number of parts that can contribute to resistance, including the quality and condition of the wheel bearings and the rotating mass. The real concern is probably how many watts are required to overcome the additional resistance in the drivetrain. That would be more difficult to determine.

My conventional road bike weighs approximately 16 pounds. The wheels are Dura Ace C24 with light tires and tubes, (with excellent bearings). My eBike weight 40 pounds, (mid drive with DT Swiss wheels, also excellent bearings). The ebike has 40mm tires and more rotational mass, and it will freewheel longer than the road bike which has less rotational mass, but the ebike has higher “rolling resistance” because of the tires and weight, (rolling resistance applies to the tire/road interface). The ebike has more “rolling resistance” and requires more wattage to propel it, but this has nothing to do with the drivetrain.

 

[jimmycash245]

I understand the premise. My comment was based on terminology. You really want to know if there is additional resistance in your drivetrain. The wheel freewheeling less does indicate additional resistance, but there are a number of parts that can contribute to resistance, including the quality and condition of the wheel bearings and the rotating mass. The real concern is probably how many watts are required to overcome the additional resistance in the drivetrain. That would be more difficult to determine.

My conventional road bike weighs approximately 16 pounds. The wheels are Dura Ace C24 with light tires and tubes, (with excellent bearings). My eBike weight 40 pounds, (mid drive with DT Swiss wheels, also excellent bearings). The ebike has 40mm tires and more rotational mass, and it will freewheel longer than the road bike which has less rotational mass, but the ebike has higher “rolling resistance” because of the tires and weight, (rolling resistance applies to the tire/road interface). The ebike has more “rolling resistance” and requires more wattage to propel it, but this has nothing to do with the drivetrain.

Yea,django
i can work out the physics. if you cannot answer the question poised just pass it by
thanks

 

[Django]

Yea,django
i can work out the physics. if you cannot answer the question poised just pass it by
thanks.

yeah jimmycash245, all things being equal, the direct drive will have more mechanical resistance.

Your question, “Does anybody have a geared Rear hub motor e Bike that could tell me what kind of rotation you can get from a geared rear hub motor?” is one that cannot be answered in a meaningful way. I guess that the logical answer would be: it depends on the initial rotational velocity. There you go.

This may be helpful to you: https://ebikes.ca/getting-started/hub-motor-options.html

 

[James340]

I have both systems.The DD has more resistance than the Geared hub.My geared hub has Regen so it does have resistance after a moment of free wheel.I ride the DD a lot without using the motor it's more to get out of traffic and to escape dog's.

 

[jimmycash245]

yeah jimmycash245, all things being equal, the direct drive will have more mechanical resistance.

Your question, “Does anybody have a geared Rear hub motor e Bike that could tell me what kind of rotation you can get from a geared rear hub motor?” is one that cannot be answered in a meaningful way. I guess that the logical answer would be: it depends on the initial rotational velocity. There you go.

This may be helpful to you: https://ebikes.ca/getting-started/hub-motor-options.html

Django

Rolling resistance-hub motor

for those using hub motors, just how much rolling resistance is there when the batteries run out and you have to start pedaling? is it really noticeable ,by say twice as hard? or is it more or less? or can you defeat the resistance by using your gears? i want to build a bike, but the hub motor...

endless-sphere.com

Bam i can do this all day long RTFQ Why, will not read the question is disturbing
have a nice day

 

[Django]

Django

Rolling resistance-hub motor

for those using hub motors, just how much rolling resistance is there when the batteries run out and you have to start pedaling? is it really noticeable ,by say twice as hard? or is it more or less? or can you defeat the resistance by using your gears? i want to build a bike, but the hub motor...

endless-sphere.com

Bam i can do this all day long RTFQ Why, will not read the question is disturbing
have a nice day

Bam yourself. Congratulations. You were able to find another person on the internet that misuses the term rolling resistance. News flash: Rolling resistance is the resistance to rolling. It’s not complicate.

Why don’t you read your own question. If you do, and if you have any intelligence, you will realize that it makes no sense because besides being written poorly, what you are asking cannot be quantified and would have no value. Think about it. You are asking for an unknown person with a geared hub to give their wheel a spin and report back. So what is the initial velocity?? Are the bearings the same as yours????

Their unit should have less mass, so that will reduce the freewheeling revolutions. Even spoke count and the type of spoke and the tire type will have an effect, not to mention how the mass is distributed. It would only be valid if all thing were equal, (minus the affect of the hub drives), and an equal initial rotational velocity was applied.

The problem with people throwing around the incorrect terms is that other people start using the term incorrectly. The worst thing is seeing the person that is misusing the term dig in their heels and refusing to learn.

 

[jimmycash245]

Hello,
Rolling Resistance experienced by bicycle rear wheel suspended is the transfer of (kinetic) energy from the wheel through the sprag with mounted Cassette and bearing preload through hysteresis. Now Add a planetary or a magnetic field and this hysteresis is magnified.
Hate it when i have to pull out the big word's Dang. i think i maybe dealing with one of them there chat-bot AI thingy

 

[Django]

Hello,
Rolling Resistance experienced by bicycle rear wheel suspended is the transfer of (kinetic) energy from the wheel through the sprag with mounted Cassette and bearing preload through hysteresis. Now Add a planetary or a magnetic field and this hysteresis is magnified.
Hate it when i have to pull out the big word's Dang. i think i maybe dealing with one of them there chat-bot AI thingy

Finding the “big words” doesn’t make that statement correct. That wasn’t even a good word salad.

'If you can't dazzle them with brilliance, baffle them with bulls**t.' ― W.C. Fields. You win. Another victory for bs.

I dislike arguing with people that refuse to learn, but it is not to anyone’s benefit to allow ignorance to stand unopposed, so here we are.

Here is a paper that explains the forces that work against all cyclists.

https://collections.lib.utah.edu/dl_files/b4/8e/b48ef26086091662c561e673d7bd990d77868437.pdf

And here is a simplified explanation:

What Causes Rolling Resistance?​

In cycling, we use pneumatic tires because of their ability to absorb the unevenness of terrain. Their deformation ability, aka the material property of the tire, and the surface the tire is riding on, contributes to hysteresis. Hysteresis is the main cause of rolling resistance in pneumatic tires. What is hysteresis? We’re glad you asked.
Hysteresis in a wheel is explain well by The National Academy of Sciences:
“A characteristic of a deformable material such that the energy of deformation is greater than the energy of recovery. The rubber compound in a tire exhibits hysteresis. As the tire rotates under the weight of the [rider+bike], it experiences repeated cycles of deformation and recovery, and it dissipates the hysteresis energy loss as heat. Hysteresis is the main cause of energy loss associated with rolling resistance and is attributed to the viscoelastic characteristics of the rubber.”
In other words, the rubber compound in pneumatic tires experiences hysteresis and the energy lost is heat and sound. Therefore, the energy required to deform the tire as it rolls onto the pavement is greater than the energy that is recovered as the tire leaves the pavement which contributes to the rolling resistance. The image below shows where the deformation and recovery occur in a tire as it rolls forward on the road.

 

[jimmycash245]

Hello

Finding the “big words” doesn’t make that statement correct. That wasn’t even a good word salad.

'If you can't dazzle them with brilliance, baffle them with bulls**t.' ― W.C. Fields. You win. Another victory for bs.

I dislike arguing with people that refuse to learn, but it is not to anyone’s benefit to allow ignorance to stand unopposed, so here we are.

Here is a paper that explains the forces that work against all cyclists.

https://collections.lib.utah.edu/dl_files/b4/8e/b48ef26086091662c561e673d7bd990d77868437.pdf

And here is a simplified explanation:

What Causes Rolling Resistance?​

In cycling, we use pneumatic tires because of their ability to absorb the unevenness of terrain. Their deformation ability, aka the material property of the tire, and the surface the tire is riding on, contributes to hysteresis. Hysteresis is the main cause of rolling resistance in pneumatic tires. What is hysteresis? We’re glad you asked.
Hysteresis in a wheel is explain well by The National Academy of Sciences:
“A characteristic of a deformable material such that the energy of deformation is greater than the energy of recovery. The rubber compound in a tire exhibits hysteresis. As the tire rotates under the weight of the [rider+bike], it experiences repeated cycles of deformation and recovery, and it dissipates the hysteresis energy loss as heat. Hysteresis is the main cause of energy loss associated with rolling resistance and is attributed to the viscoelastic characteristics of the rubber.”
In other words, the rubber compound in pneumatic tires experiences hysteresis and the energy lost is heat and sound. Therefore, the energy required to deform the tire as it rolls onto the pavement is greater than the energy that is recovered as the tire leaves the pavement which contributes to the rolling resistance. The image below shows where the deformation and recovery occur in a tire as it rolls forward on the road.

Hello,
Calm down, look at the text closely. Look up the words you don’t fully understand. Reflex on the text and you will see this is not a word salad. If on the other hand you have dug your heels in the ground that the Only definition or the usage for the term “Rolling Resistance” is Only applicable to a Tire rolling on a surface then…. I actually pity you. I believe I have been patient and engage with some humor at your inflexible approach, but there are many Applications where the term “Rolling Resistance” is applicable. As far as am concern I have done all I can to help you understand that point. Now you can keep this thread alive but only with yourself. Good Luck in your endeavor’s.

 

[Django]

Hello

Hello,
Calm down, look at the text closely. Look up the words you don’t fully understand. Reflex on the text and you will see this is not a word salad. If on the other hand you have dug your heels in the ground that the Only definition or the usage for the term “Rolling Resistance” is Only applicable to a Tire rolling on a surface then…. I actually pity you. I believe I have been patient and engage with some humor at your inflexible approach, but there are many Applications where the term “Rolling Resistance” is applicable. As far as am concern I have done all I can to help you understand that point. Now you can keep this thread alive but only with yourself. Good Luck in your endeavor’s.

I am calm, thanks.

Sorry man, but your attempt to make yourself seem knowledgeable falls flat every time. I understand the terms. It’s the context that is senseless. If you think that you are correct and that your gibberish is intelligible, then I pity you.

Rolling resistance and resistance within a drivetrain are not the same thing. Your inability to grasp that very simple concept is troubling.