I know their meanings, but i just can't get my head around them.

[mountainsport]

Hi again to all,

Nothing exciting to ask really, but is it my low level of understanding or is it not explained properly for people who find it hard to understand both of these words in principle ?

Who can please explain to me in simple A,B,C terms and also giving an example to back up their explanation.

Question: What is the difference between TORQUE & ACCELERATION ? PLUS HOW DO THEY BOTH DIFFER?

MS. THANK YOU FOR YOUR TIME..........

 

[ghouluk]

3am, and just finished fixing the mail server (the joys of running your own business), a fine time to break out my 20 year old degree knowledge

Most people usually ask to explain the difference between torque and power (which is easy) but let me give it a go.

Torque is a measure of the force applied to rotate a lever around a point, in cycling terms this would be the amount of force applied on the crank (by your foot on the pedal) to rotate it.

Linear acceleration is just force times * mass, but its unrelated to torque, so i'm guessing you want angular acceleration

angular acceleration is a measure of the change in velocity over time, in cycling terms this would be a way of expressing e.g. i turn the cranks at 2 turns per second and increase it to 4 turns per second over 5 seconds or the angular velocity changes from x to y in time z.

the relationship between the two is torque = inertia * angular acceleration, this is useful for comparing the two again in a cycling context, pressing the pedal and hence turning the crank, the faster you turn the crank over time the faster you accelerate, the resistance to turning the crank is the inertia, the amount of effort you use to overcome the resistance and turn the crank is torque (ish) so you need lots of torque to start in top gear on a hill, even though you don't accelerate fast as you have a great deal of inertia to overcome.

The other way that might make more sense is its simply a rotational way of expressing

linear - force = mass * acceleration
rotational - torque = inertia * rotational acceleration

hmmm why do i get the feeling this is going to be nonsense when i read it again tomorrow

feel free to correct me - time for bed!

 

[funkylyn]

hmmmmm ...........good question MS but I dont think we have had a simple non techie woman related reply there either

Acceleration just describes that you are going faster without saying how......

Torque is to describe how the power is getting there to make you go faster......

Hang on, Im off for my first coffee and will try to engage brain better later......well, anyway, you said simple and, well, thats a simple answer but might not be what you are asking and I really need my caffeine.....and a vape, some of us have just woken up you know.....

Lynda

 

[Deleted member 4366]

I think what you want is the relationship between torque and acelleration rather than the difference.

Torque is the turning force in the wheel. Its like a force because it results in a force between the tyre and road, which drives you forward.

Acelleration is what it does to you. It affects your speed in any particular situation.

If you're stationary, and apply torque to the wheel, your speed will increase until the torque is countered by the backward forces of wind, friction and gravity (hills)

The more torque you have, the faster you accelerate until you reach the top speed.

If you're on a hill and you don't t have enough torque, you'll slow down and stall out. If you have lots of torque, you can acellerate to a higher speed.

Motor torque isn't constant. It decreases as the motor speeds up, so when people give a figure for it, it's meaningless unless they say at what wheel speed it has that figure, which they never do, so never try and compare torques.

Torque is of interest to us because it determines how well you can climb hills. The more torque you have at the back wheel, the steeper it will climb without stalling; however, the speed at which it gives that torque is also very important.
Crank-drives can multiply torque by using a lower gear, but then you go slower. You can pull a battleship up any hill you want with a 250W motor if you have low enough gearing, but only at a speed so slow that you wouldn't notice it moving.

Don't ask about power. It's even more complicated

 

[timidtom]

'I am a bear of very little brain, and long words bother me ...'
I wish I'd said this but Pooh Bear beat me to it.
Good morning world, and may the sun shine on you as you e-ride today!
Tom

 

[funkylyn]

'I am a bear of very little brain, and long words bother me ...'
I wish I'd said this but Pooh Bear beat me to it.
Good morning world, and may the sun shine on you as you e-ride today!
Tom

Aww....and the same to you Tom, I hope it shines long and hot on me as I intend topping up my tan, not riding, today, but I might get out this evening and do a quick burn to chard and back

Lynda

 

[trex]

Torque and acceleration are related to one another like radius (torque) and circomference (acceleration). Torque is what makes the wheel turn faster, acceleration is how much faster the wheel turns. In effect, the bigger the torque, the quicker you gain speed. Bigger wheels gain speed faster than smaller wheel at the same torque.
You pay for acceleration. Muliplied acceleration (m/s2) by your mass (M) = power in Watts.
As you cannot change your body mass, your money purchases directly Watts on the ground. The ratio between Watts from the battery (input power) and Watts on the ground (output power) is the yield. You will want a big battery, big motor and big yield.
Now this is interesting. How many Watts you can get out of a kit depends on motor speed. There is a sweet zone where the motor gives maximum power for the same money. That's where crank motor pays better than hub motor because it will give a better yield and you can keep the motor in its sweet zone more of the time.

 

[Deleted member 4366]

There is a sweet zone where the motor gives maximum power for the same money. That's where crank motor pays better than hub motor because it will give a better yield and you can keep the motor in its sweet zone more of the time.

Great theory, but in practice it doesn't work out like that. With drive through the gears, it's not so easy to keep the motor in its sweet spot. It still has the full range of RPM in any gear and you've little idea of what speed it's turning at. The only time it's more efficient compared with a hub-motor is when the hub-motor is struggling up a steep hill. Most of the other time it has no advantage, and at times it had disadvantage. The end result is that they're about the same on normal roads.

Most of the crank-drives require that you pedal harder than most hub-drives, which gives the illusion of better range and higher efficiency. The new Chinese crank-drives don't require you to pedal so hard because they have a different type of controller They struggle to get the same range as a Bosch or Panasonic only because you don't have to pedal so hard.

 

[trex]

I have tried quite a few e-bikes and found that hub motors make you lazy.
Most of them require so little effort to go on the flat that you get little benefit from riding e-bikes. Crank bikes on the other hand let you control how much you want to pedal and more importantly, let you control your cadence.
Intuitively, you just know which assistance setting and gear to use to get the best out of your bike and to suit your mood, especially if the bike is derestricted. You have much less choice on hub bikes so you end up having to buy a big hub motor to compensate. Problem is, big motor will reduce your physical effort even further.

 

[funkylyn]

I absolutely agree trex, I can remember the difference I found when changing from my Windsor to the Tonaro.....first few rides I thought I was going to die lol

I certainly felt like I was having to work much harder for my pleasure......never a bad thing....

Lynda

 

[flecc]

I have tried quite a few e-bikes and found that hub motors make you lazy.

Certainly this was true for me. Switching from a Panasonic crank drive to hub motor e-bikes wrecked my cycling fitness very quickly. One factor in that was that the hub motor bikes were far harder to ride without power, where the Panasonic unit bike was almost as easy as any normal bike.

 

[mountainsport]

hmmmmm ...........good question MS but I dont think we have had a simple non techie woman related reply there either

Acceleration just describes that you are going faster without saying how......

Torque is to describe how the power is getting there to make you go faster......

Hang on, Im off for my first coffee and will try to engage brain better later......well, anyway, you said simple and, well, thats a simple answer but might not be what you are asking and I really need my caffeine.....and a vape, some of us have just woken up you know.....

Lynda

Lynda my sweet love, simple answer yes, but please get back to me after your caffeine treat. xxx

MS.

 

[mountainsport]

And about the power now d8veh? Just kidding. Therefore in other words acceleration starts off first then torque ends up second, so does acceleration determine the cut off point for the torque or does the torque determine when for the acceleration to take over? (Sorry still trying).

MS.

 

[mountainsport]

Torque and acceleration are related to one another like radius (torque) and circomference (acceleration). Torque is what makes the wheel turn faster, acceleration is how much faster the wheel turns. In effect, the bigger the torque, the quicker you gain speed. Bigger wheels gain speed faster than smaller wheel at the same torque.
You pay for acceleration. Muliplied acceleration (m/s2) by your mass (M) = power in Watts.
As you cannot change your body mass, your money purchases directly Watts on the ground. The ratio between Watts from the battery (input power) and Watts on the ground (output power) is the yield. You will want a big battery, big motor and big yield.
Now this is interesting. How many Watts you can get out of a kit depends on motor speed. There is a sweet zone where the motor gives maximum power for the same money. That's where crank motor pays better than hub motor because it will give a better yield and you can keep the motor in its sweet zone more of the time.

Seeping in a little bit more now, torque equals strength, muscle power.

MS.

 

[Deleted member 4366]

Most hub-bikes of today have control systems with several levels of PAS. You're right that they allow you to be lazy; however, they also allow you to pedal as hard as you want by setting the appropriate level. This characteristic has nothing to do with the type of drive (crank vs hub). It depends on the control system. Chinese crank-drives including Tonaros (sorry Lynda) have the same control system as their hub motors, so they're the same. Some European hub motors have the same control system as their crank motors, so you have to pedal harder on them too. It's nothing to do with the motor, neither is it anything to do with the type of sensor. It depends on the controller software. The programmer can make it any way he/she wants.

Things are changing rapidly regarding control systems. What I've said applies to today's bikes. I know that the Chines are rapidly catching up the others, but hopefully, the others are doing something to keep their lead.

 

[mountainsport]

Aww....and the same to you Tom, I hope it shines long and hot on me as I intend topping up my tan, not riding, today, but I might get out this evening and do a quick burn to chard and back

Lynda

Lynda, I hope that you are applying on your sun screen lotion with precise torque and acceleration

MS. xxxxxxxxxxxx

 

[mountainsport]

i have tried quite a few e-bikes and found that hub motors make you lazy.
Most of them require so little effort to go on the flat that you get little benefit from riding e-bikes. Crank bikes on the other hand let you control how much you want to pedal and more importantly, let you control your cadence.
Intuitively, you just know which assistance setting and gear to use to get the best out of your bike and to suit your mood, especially if the bike is derestricted. You have much less choice on hub bikes so you end up having to buy a big hub motor to compensate. Problem is, big motor will reduce your physical effort even further.

true,true,true and true again for being truthful in the truth.

Ms.

 

[KirstinS]

Here is my version (for non engineers like myself - I know this is oversimplified at best : )

Acceleration is the word that describes increasing your speed over time.

Example, get on your bike and go. In the first second you are travelling at 3mph , in the second 6mph, the third 9mph and so on. Congrats - you are accelerating !! That's all there is to it.

Torque is a word used to describe the strength of the twisty motion your motor makes when it is switched on.

Example - think of a kids handheld windmill. The type they sell on seafronts around then uk. When power is applied (wind rather than electric) they turn around. Stick your finger in the way - it stops. Very low torque indeed

Now think of your wheel. Power gets it moving , stick your finger in the spokes and you will no longer have a finger ! Much higher torque - high enough to overcome the drag of your finger

Quite right too as the torque an ebike needs to produce must be enough to overcome the combined weight of you and your bike (not just a finger !) and added to that it is expected to push you up hills. Some bikes are better than others at this - Lower torque means not so good hill climbing, higher means better

Higher torque also means better acceleration - more twisty strength means it is less dragged down or stopped by weight and hills

 

[funkylyn]

Lynda my sweet love, simple answer yes, but please get back to me after your caffeine treat. xxx

MS.

Oh my dear MS, Im getting a headache now...why not just do as I do and enjoy the ride without having to know all the reasons why it goes like it does....its far less stressful I find

..... sorry, Im being a bit facetious, but Ive just inadvertently had a mouthful of vaping juice whilst changing a tank with my teeth, ( dont ask lol ) and its not my favourite tipple

I do, however, admire your enquiring technical mind.........

Lynda

 

[funkylyn]

Lynda, I hope that you are applying on your sun screen lotion with precise torque and acceleration

MS. xxxxxxxxxxxx

Never use it MS......a bit like me not wearing a helmet.....I must like living on the edge

Lynda