Just to extend a little bit from the end of the video: Since the resultant normal force is non-uniform and lean towards the front edge of the contact patch, it does not pass through the center of the tire and create a moment that resists its rotation.
@@halfmv2 I tend to believe that energy lost due to intermolecular friction, i.e hysteresis energy loss, and energy lost due to negative torque are two different matters, although they both are the consequences of hysteresis effect. From an energy perspective and consider a rubber element approaching and departing the contact patch. Even without considering losses due to molecular friction, the element already need to spend more energy when approaching to overcome higher pressure and receive less energy when departing since experiencing lower pressure. If indeed two separate losses, it might be possible that hysteresis energy loss in most cases dwarf the lost due to negative torque. But I mean, I am not sure either...lol
Didn't think about that until I read this lol Who's gonna believe it's just moving on it's own? Just put a hand in there, you know these people are idiots.
I know the term from SpeedFan, where you set temperature thresholds for your computer fans to activate, and hysteresis is how much the temperature can drop back down before the fans will deactivate again.
These explanations are fascinating. Very simple, straight forward and well illustrated. The way is explained reveals a lot of links between different fields of knowledge. Very well explained.
I was tired of my tires wearing out so quickly, so I decided to make a set out of tungsten carbide. Rolling resistance and hysteresis were dramatically reduced. I expect wear to increase by several orders of magnitude. I'm still working on traction, road holding ability, etc.
4:47 yup, that resultant force acts away from the center of the wheel. Causing a moment/torque opposite to the direction of the wheel's rotation. Also, the heavier the vehicle, the higher this resultant force hence higher rolling resistance. Also, at a higher velocity, the tires actually expand outward which reduces the rolling resistance. This is one reasons why a vehicle operating at highway speed is more efficient than in cities.
A very well-made video, especially with the part on how the hysteresis results in an uneven normal force distribution. Thank you for explaining this so clearly!
Dear author. I have a request for you. Whenever you make such interesting videos, make sure you add formulas in them . This will show the importance of calculations to our society and upcoming engineerings. I know you know what i want to say . People run from formulas and calculations but they never run from theories. So we have make sure when we are explaining theoretically , we show them importance and use of formulas at the time. Thanks , i hope this comment could reach out to you.
Hysteresis has application in Human physiology too. Learned in 1'st year of my med school. Lung compliance during expiration and inspiration follow a hysteresis curve and deviation from standard can help make diagnosis of restrictive or obstructive lung diseases.
"The resultant becomes zero velocity means the contact point has no relative motion with thre road and frictional force should also be zero. Because of this a perfect tire can roll forever" on any frictional surface. Thank you for this perfect explanation. Many thanks.
No. It is to guide it on rails and increase the load bearing capacity, as the load is transmitted to the road along steel beams and wooden or concrete posts with a large area for rails and just four patches for tyres. Those are just two reason on top of my head, I'm sure there's more.
Roberto I’m sure it is a contributing factor as to why both are steal, being both are steal there barely deform to eachother upon contact and movement. That also means that they wouldn’t wear as quickly as tires would on a road. When rails were introduced, vehicles that could transport that much material so easily were few to none, so having such an efficient mode of transport was necessary.
These automotive engineering videos are great. I learned a long time ago to overinflate new tires 5 psi above spec then bleed the air out until it's at spec vs inflate to spec and let it lose a few psi on its own. They all do.
What about: Coefficient of Deceleration due to other factors? Such as 1: Chemical properties of the materials used. 2: Road and or friction surfaces in contact 3: Amount of force exerted at what RPM? 4: At the time of the specific interval of experiment, how much acceleration was active or zero acceleration, obviously that resulted in deceleration after and or due certain conditions. 5: wind factor. 6: Quality of the interactive surfaces 7: E.g. if braking is applied considering anti-lock braking, vehicle or tires will sink more and increase the friction contact area. 8: values may differ for every vehicle considering, type, make, class, horsepower, automated tech, etc. So for every given scenario General equation must include scenarios specific factorial equations to calculate accurate and precise values, for example as in ballistics calculations.
The way you explained it is awesome, I am highly impressed. Now I know why my vehicle consumes more fuel with tyre having less air in it than stipulated level. Keep up the good work.
When practical, I usually run my tires at maximum pressure. Less deformation creates a smaller patch area, which produces a rougher ride, but reduces rolling resistance so slightly improves fuel economy.
lol but you also have less contact patch for corners so you need to take them slower and accelerate on the next straight more -> losing fuel economy :)
Carlos Reis That’s like saying you don’t need a seatbelt because almost all the time you aren’t in a crash. Just because you don’t need it 99% of the time doesn’t mean you shouldn’t wear it to be prepared for that 1%
@Issac Brewer @Keisuke Takahsai You boys are off in the land of theory. Here in the real world, I'm driving heavy-duty trucks with 80 psi in the tires. On-road, or off, we drive fast around here. And we don't slow down corners, little cars, or people who can't drive well enough to keep up.
If I had enough money to spend, I wound spend you some after this fantastic video! Sadly I am just a mechanical engineering student. But I wish you good luck and a large future on youtube!
This video I can say I have learnt hysteresis very properly. 👍🙏👍 No one can be better than youin explaining this type of town but we can ever imagine before
My understanding of rolling hysteresis incorporates a strong relationship with rawhide: "Keep Rollin', Rollin', Rollin', Though the streams are swollen, Keep them dawwgies rollin', Rawhide!"
The hysteresis should largely be due to the fact that the compression and decompression are not instantaneous, and so the heat generated by compression is partially lost so that the system has less energy to 'decompress' the rubber by the time its no longer being compressed.
In the virtual experiment environment I guess they added some Force opposing the normal, then the simulation only focuses on energy lost by expansion delay. If ground friction was considered, the tire would roll even less
This is the "friction" that makes the car slow down. The only contributes of energy loss that have to be added to this effect are the aerodynamic friction and the friction between the components of the car's trasmissions, and possibly the ground slope.
@@halfmv2 Shouldn't we have a contact 'line' to have zero velocity at the bottom of the wheel? If it is a rubber wheel, the contact area would be a surface rather than a line; therefore the bottom of the wheel should have a velocity relative to the ground. If you move a line on the wheel, you can see that there is a distance that must be traveled between where it touches the ground and leaves the ground, so technically there is a rubbing of surfaces. However, the direction of the kinetic friction would change depending on whether you are speeding up or slowing down. If you accelerate a vehicle, the kinetic friction is the force that makes you accelerate; therefore, in this case, the only force against movement would be hysteresis energy loss while accelerating. But if you are slowing down, the kinetic friction would also contribute to the opposing forces.
@@halfmv2 I thought a bit more about my first question, and I came to the conclusion that there is no need for a contact 'line' to have zero velocity relative to the ground. We can have a static connection between the ground and the wheel even if there is contact 'surface'. I think what I previously thought is true if there is slippage and a car is accelerating or the driver is pressing the brakes. However, If there is no slippage, the tire loses energy only from the hysteresis energy loss besides the air resistance, as you said.
👍🏻 great content, as expected. Someone on TH-cam placed a GoPro inside a tire/rim and drove around his neighbourhood with the wheel mounted to his car. Interesting!
Is there a material with reverse hysteresis, meaning decompression is faster than the compression? If so, how would it affect rolling resistance if applied on wheels?
I think that’s impossible, considering hysteresis occurs from energy losses in the material, reverse hysteresis would have to result from energy gained somewhere.
I knew it!! I was tired of people saying "A low tire will cause bad gas mileage because the contact patch is wider when the air is low" WRONG. Gas mileage is worse with low tires because of the energy loss associated with that rubber being mushy gushy.
A great explanation of how the hysteresis of rubber creates a rolling resistance. But what about the relatively large contact patch area? Since the front and back of the patch are a different distance from the axis than the middle, there must be some tangential flexing of the rubber or slippage along the road surface? How does this come into things?
How would you lower the rolling resistance of a tire made of an elastic material(rubber, polyurethane, or whatever)? I heard adding Silica to rubber decreases the rolling resistance.
there are patterns used in the weave of the belt plies and radial weave that decrease roll resistance but make the tyre directional. Materials used in the belts, walls and radial banding also vary to reduce roll resistance. Reducing the tyres weight and moving the weight balance closer to the center of there rotaional axis also reduce roll resistance losses due to centrifugal loss. Stiffening the side wall without reducing. reducing surface contact patch pinching and spreading by changing tread patterns and varying tread densities across the contact patch. They will also have there own 11 herbs and spices they use for the rubber. they may add sillica (glass) , plastic, PTFE, kevlar and many other ingrediants to reduce internal frictions and increase traction. For instance silica will make the compound harder wearing and stiffer but will also make the tyre more thermally conductive and introduce more road noise transmission. as such it may make a good addition to the primary tread sections but will be a poor choice for the side wall.
This is why having your tires properly inflated improves mpg.. lower rolling resistance. Some people even say to put 10% above what the car specs say to get the best mpg. Air also expands the hotter it gets so its most accurate to check the tire psi with as little driving as possible.
as a cyclist (and engineering dropout), my only question, is "why do wider tires have lower rolling resistance?" From the video I can only surmise that a wider contact patch produces a less long contact patch, getting it closer to that perfect line, thus two things happen: the tire deforms less and the differential in normal forces is minimized (plus the normal force is much closer to the axle, minimizing the moment), and the tire turns less mechanical energy into heat through internal friction. is that assessment right?
Just to extend a little bit from the end of the video: Since the resultant normal force is non-uniform and lean towards the front edge of the contact patch, it does not pass through the center of the tire and create a moment that resists its rotation.
Yep, the video is missing that final bit to come back around and answer the original question fully. Thanks for putting it in words.
@@halfmv2 I tend to believe that energy lost due to intermolecular friction, i.e hysteresis energy loss, and energy lost due to negative torque are two different matters, although they both are the consequences of hysteresis effect. From an energy perspective and consider a rubber element approaching and departing the contact patch. Even without considering losses due to molecular friction, the element already need to spend more energy when approaching to overcome higher pressure and receive less energy when departing since experiencing lower pressure. If indeed two separate losses, it might be possible that hysteresis energy loss in most cases dwarf the lost due to negative torque. But I mean, I am not sure either...lol
Ah so these two effects combined are why low PSI tires cause poor gas mileage.
@@ImBoredToo oh interesting !
Thank you for that extra information. I didn't think this way.
i like how the animation has a hand pushing the tire.
Details. XD
Grimgaunt R6 gamer ????
Didn't think about that until I read this lol
Who's gonna believe it's just moving on it's own? Just put a hand in there, you know these people are idiots.
🤣
Well someone has gotta roll it out after all jajaja
I knew about hysteresis but this gave me new knowledge.
Was going to make same comment.
Yep
Hysteresis is also in transformers isn't it? ( not the movie transformers but those on electric factory)
@@killerdroid99 yes hysteresis loss in magnets
I know the term from SpeedFan, where you set temperature thresholds for your computer fans to activate, and hysteresis is how much the temperature can drop back down before the fans will deactivate again.
These explanations are fascinating. Very simple, straight forward and well illustrated.
The way is explained reveals a lot of links between different fields of knowledge.
Very well explained.
I was tired of my tires wearing out so quickly, so I decided to make a set out of tungsten carbide. Rolling resistance and hysteresis were dramatically reduced. I expect wear to increase by several orders of magnitude. I'm still working on traction, road holding ability, etc.
Bolt on some spikes like a golfer's shoes and you'll be fine.
Wow
You expect wear to increase?
@@Steamrick My mistake, sir. I should have said "wear resistance and durability"
The local council wants to know where to send the bill for the damaged tarmac?
Guys you should be awarded. Making minute details and explaining them via animation could be enervated. Appreciated! Thank you.
4:47 yup, that resultant force acts away from the center of the wheel. Causing a moment/torque opposite to the direction of the wheel's rotation. Also, the heavier the vehicle, the higher this resultant force hence higher rolling resistance. Also, at a higher velocity, the tires actually expand outward which reduces the rolling resistance. This is one reasons why a vehicle operating at highway speed is more efficient than in cities.
Thanks, most accurate depiction till now.
I have been curious about his topic for so long now, but never found good content on it. Great Job!
A very well-made video, especially with the part on how the hysteresis results in an uneven normal force distribution. Thank you for explaining this so clearly!
Dear author. I have a request for you. Whenever you make such interesting videos, make sure you add formulas in them . This will show the importance of calculations to our society and upcoming engineerings. I know you know what i want to say . People run from formulas and calculations but they never run from theories. So we have make sure when we are explaining theoretically , we show them importance and use of formulas at the time. Thanks , i hope this comment could reach out to you.
he explained clearly without formula
Hysteresis has application in Human physiology too. Learned in 1'st year of my med school. Lung compliance during expiration and inspiration follow a hysteresis curve and deviation from standard can help make diagnosis of restrictive or obstructive lung diseases.
Thanks for the extra info
"The resultant becomes zero velocity means the contact point has no relative motion with thre road and frictional force should also be zero. Because of this a perfect tire can roll forever" on any frictional surface. Thank you for this perfect explanation. Many thanks.
Its great to find an rbd concept explained so lucidly. Rbd has always been a nightmare for jee aspirants . 😅
Long story short this is why trains have steel wheels on steel rails.
Too bad our roads can't be smooth as rails. If we had solid metal tires that ride would break your spine. 😆 🤣
@@justinhackstadt6677 The resistance of an air filled tire is less than that of a solid one on uneven surfaces.
No. It is to guide it on rails and increase the load bearing capacity, as the load is transmitted to the road along steel beams and wooden or concrete posts with a large area for rails and just four patches for tyres. Those are just two reason on top of my head, I'm sure there's more.
Roberto I’m sure it is a contributing factor as to why both are steal, being both are steal there barely deform to eachother upon contact and movement. That also means that they wouldn’t wear as quickly as tires would on a road. When rails were introduced, vehicles that could transport that much material so easily were few to none, so having such an efficient mode of transport was necessary.
Loco! Motion! Shits crazy mang
youtube algorithm - You need to know this before you sleep
aliazar pisor, I saw this when I woke up...
morning here
Going to be noon here
About to go to sleep aha
These automotive engineering videos are great. I learned a long time ago to overinflate new tires 5 psi above spec then bleed the air out until it's at spec vs inflate to spec and let it lose a few psi on its own. They all do.
"This video was sponsered by... BMW!"
I thought it was the Learn Engineering logo, damn i need glasses
He Just use and old model he cant do and new model for evry video
wow, i never thought i would find an answer to this question.
Who knew that such a simple thing can be this nuanced.
What about: Coefficient of Deceleration due to other factors? Such as
1: Chemical properties of the materials used.
2: Road and or friction surfaces in contact
3: Amount of force exerted at what RPM?
4: At the time of the specific interval of experiment, how much acceleration was active or zero acceleration, obviously that resulted in deceleration after and or due certain conditions.
5: wind factor.
6: Quality of the interactive surfaces
7: E.g. if braking is applied considering anti-lock braking, vehicle or tires will sink more and increase the friction contact area.
8: values may differ for every vehicle considering, type, make, class, horsepower, automated tech, etc. So for every given scenario General equation must include scenarios specific factorial equations to calculate accurate and precise values, for example as in ballistics calculations.
The way you explained it is awesome, I am highly impressed. Now I know why my vehicle consumes more fuel with tyre having less air in it than stipulated level. Keep up the good work.
This is really cool. Videos like these are why I love being subscribed to channels like these where I get content that's almost nowhere else
When practical, I usually run my tires at maximum pressure. Less deformation creates a smaller patch area, which produces a rougher ride, but reduces rolling resistance so slightly improves fuel economy.
Smaller patch area also means less friction in wet conditions which is needed to stop. 🤷♂️ pros and cons.
@@isaacbrewer5616 almost the time is dry road.........
lol but you also have less contact patch for corners so you need to take them slower and accelerate on the next straight more -> losing fuel economy :)
Carlos Reis That’s like saying you don’t need a seatbelt because almost all the time you aren’t in a crash. Just because you don’t need it 99% of the time doesn’t mean you shouldn’t wear it to be prepared for that 1%
@Issac Brewer @Keisuke Takahsai You boys are off in the land of theory. Here in the real world, I'm driving heavy-duty trucks with 80 psi in the tires. On-road, or off, we drive fast around here. And we don't slow down corners, little cars, or people who can't drive well enough to keep up.
Thanks for making these great educational videos
I am not an engineer, nor am I a physicist, but I do grasp the nuances of hysteresis.
Thank you for the insite!
unsprung mass would be a great video
I agree, it's not something most people know about.
How good is to understand english, I from Brazil and this channel helps me a lot to understanding those things. |Thank you so much!
I found this fascinating especially the part about non uniform load bearing! Thankyou for the video explaination
If I had enough money to spend, I wound spend you some after this fantastic video!
Sadly I am just a mechanical engineering student.
But I wish you good luck and a large future on youtube!
A TH-cam channel called “Warped Perception” put a GoPro camera inside a tire and drove it. Very relevant to this video. Worth watching.
cannot find a better channel illustrating scientific stuffs
Guess we finally know what happens when the rubber meets the road
This video I can say I have learnt hysteresis very properly. 👍🙏👍 No one can be better than youin explaining this type of town but we can ever imagine before
Did I just watch the most subtle BMW advertisement...?
That wasn't subtle
Finally I understood rolling resistance as opposed to friction!😊
The most expected video from a great channel like this
I had an intuition why this happened, but now I know it scientifically. Thanks.
Fascinating and informative. I learned something new about cars, first in a decade
My understanding of rolling hysteresis incorporates a strong relationship with rawhide:
"Keep Rollin', Rollin', Rollin',
Though the streams are swollen,
Keep them dawwgies rollin', Rawhide!"
Lol
The hysteresis should largely be due to the fact that the compression and decompression are not instantaneous, and so the heat generated by compression is partially lost so that the system has less energy to 'decompress' the rubber by the time its no longer being compressed.
You are the only one whome i subscribed first❤️❤️❤️
Nice video , i learn a lot from your videos!
Then this hysteresis energy loss is additional to the frctional energy loss that we've normally presumed for slowing a car ??
In the virtual experiment environment I guess they added some Force opposing the normal, then the simulation only focuses on energy lost by expansion delay. If ground friction was considered, the tire would roll even less
This is the "friction" that makes the car slow down. The only contributes of energy loss that have to be added to this effect are the aerodynamic friction and the friction between the components of the car's trasmissions, and possibly the ground slope.
@@halfmv2 Shouldn't we have a contact 'line' to have zero velocity at the bottom of the wheel? If it is a rubber wheel, the contact area would be a surface rather than a line; therefore the bottom of the wheel should have a velocity relative to the ground. If you move a line on the wheel, you can see that there is a distance that must be traveled between where it touches the ground and leaves the ground, so technically there is a rubbing of surfaces. However, the direction of the kinetic friction would change depending on whether you are speeding up or slowing down. If you accelerate a vehicle, the kinetic friction is the force that makes you accelerate; therefore, in this case, the only force against movement would be hysteresis energy loss while accelerating. But if you are slowing down, the kinetic friction would also contribute to the opposing forces.
@@halfmv2 I thought a bit more about my first question, and I came to the conclusion that there is no need for a contact 'line' to have zero velocity relative to the ground. We can have a static connection between the ground and the wheel even if there is contact 'surface'. I think what I previously thought is true if there is slippage and a car is accelerating or the driver is pressing the brakes. However, If there is no slippage, the tire loses energy only from the hysteresis energy loss besides the air resistance, as you said.
99% of the resistance in a car will be air resistance. Obviously will depend on speed.
perfect illustration for the uniform force distribution on the contact patch
yes! i'm pumped for the vehicle dynamics series!
Bah, you can't end an episode on a cliff hanger like this! I want to know about the rolling resistance
Thanks a lot. I always wanted to know why is there rolling friction but never got to know until I watched this video.
This channel just never disapoints
I love how this was explained!
Thank you
3:59 expanssion is spelled wrong. This is a great vid though.
Grammar nazi spotted
Dank Ju mein GrammaFuhrur
I commented about it too.
A good little doco. Thank you.
thank you so much :') i have no words to thank you enough, pls make more videos like this, it was a great help
This is kinda mind blowing.
great exp as usual
👍🏻 great content, as expected.
Someone on TH-cam placed a GoPro inside a tire/rim and drove around his neighbourhood with the wheel mounted to his car. Interesting!
Excellently Explained
Is there a material with reverse hysteresis, meaning decompression is faster than the compression? If so, how would it affect rolling resistance if applied on wheels?
I think that’s impossible, considering hysteresis occurs from energy losses in the material, reverse hysteresis would have to result from energy gained somewhere.
actually learned something new for once, pleasantly surprised
I appriciate your informative videos thank you from japan
Underrated channel
This was super insightful! Thank you.
Recommended after watching rogue tires gone wild videos.
I knew it!! I was tired of people saying "A low tire will cause bad gas mileage because the contact patch is wider when the air is low" WRONG. Gas mileage is worse with low tires because of the energy loss associated with that rubber being mushy gushy.
Thanks!
Excellent narration and animation !
Nice Topic Selection ! Thanks and well Explained !
Excellent
Thanks for uploading these vedios
Very helpful
exellent explanation. great. this movie makes me smarter.
Another awesome video! Thank you!
Your animations are fantastic
Wow.. what a clear concept.. thanku sir
Thank you so much very good explanation
Excellent and informative explanation !
Wow.... clearly explained !!
Wow loved it! They didn't teach us this in pow eng school 😊
Very much interesting,keep it up 👍👍
A great explanation of how the hysteresis of rubber creates a rolling resistance. But what about the relatively large contact patch area? Since the front and back of the patch are a different distance from the axis than the middle, there must be some tangential flexing of the rubber or slippage along the road surface? How does this come into things?
Great video, thank you.
Great video. Be good to see a follow up on why wider tyres have lower rolling resistance.
P.s. only one S in expansion
nice video sabine and team...............keep up your great work. LOVE.....
How would you lower the rolling resistance of a tire made of an elastic material(rubber, polyurethane, or whatever)?
I heard adding Silica to rubber decreases the rolling resistance.
Harder compounds and higher pressure
there are patterns used in the weave of the belt plies and radial weave that decrease roll resistance but make the tyre directional. Materials used in the belts, walls and radial banding also vary to reduce roll resistance.
Reducing the tyres weight and moving the weight balance closer to the center of there rotaional axis also reduce roll resistance losses due to centrifugal loss.
Stiffening the side wall without reducing.
reducing surface contact patch pinching and spreading by changing tread patterns and varying tread densities across the contact patch.
They will also have there own 11 herbs and spices they use for the rubber. they may add sillica (glass) , plastic, PTFE, kevlar and many other ingrediants to reduce internal frictions and increase traction.
For instance silica will make the compound harder wearing and stiffer but will also make the tyre more thermally conductive and introduce more road noise transmission. as such it may make a good addition to the primary tread sections but will be a poor choice for the side wall.
How fitting.... upon finishing tgus video Google played a geico ad depicting a flat tire.
Thanks for this video 👍
Awesome explaination
Awesome video..please make more videos on vehicle dynamics
This is why having your tires properly inflated improves mpg.. lower rolling resistance. Some people even say to put 10% above what the car specs say to get the best mpg. Air also expands the hotter it gets so its most accurate to check the tire psi with as little driving as possible.
Waaw, this was explained well.
Great knowledge library
Nice video and very informative and very entertaining and very satisfaction more videos.
What an informative video, just keep making more 👍🏼🙏🏼
very clear explanation
‘Knowledge is power’
Amazing!
Very much need ...gate added rolling friction in its syllabus
How did you guys animate the tire deformation? It looks really good!
Omg so trams and trains are awesome
amazing explanation
as a cyclist (and engineering dropout), my only question, is "why do wider tires have lower rolling resistance?" From the video I can only surmise that a wider contact patch produces a less long contact patch, getting it closer to that perfect line, thus two things happen: the tire deforms less and the differential in normal forces is minimized (plus the normal force is much closer to the axle, minimizing the moment), and the tire turns less mechanical energy into heat through internal friction. is that assessment right?
Beginner rollerskater here. I am following on this question!
Please make a detailed video on tyre dynamics.
Great teachers... Love you guys ❤️❤️