A Cars forum. AutoBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » AutoBanter forum » Auto newsgroups » Technology
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

Rubbing the tire on the road, is it really mathematically simple?



 
 
Thread Tools Display Modes
  #11  
Old May 13th 19, 02:16 PM posted to rec.autos.tech
Xeno
external usenet poster
 
Posts: 363
Default Rubbing the tire on the road, is it really mathematically simple?

On 13/5/19 7:48 pm, dsi1 wrote:
> On Saturday, May 11, 2019 at 8:28:26 PM UTC-10, Xeno wrote:
>>>

>> What they really say;
>> Don't sweat the petty things but
>> don't get caught petting the sweaty things.
>>
>> --
>>
>> Xeno
>>
>>
>> Nothing astonishes Noddy so much as common sense and plain dealing.
>> (with apologies to Ralph Waldo Emerson)

>
> Don't pet the sweaty things? I like it. The Lord is a shoving leopard.
>

I speak from experience! LOL

--

Xeno


Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)
Ads
  #12  
Old May 13th 19, 02:27 PM posted to sci.math,sci.physics,rec.autos.tech
Xeno
external usenet poster
 
Posts: 363
Default Rubbing the tire on the road, is it really mathematically simple?

On 12/5/19 3:14 pm, Sylvia Else wrote:
> On 12/05/2019 7:13 am, micky wrote:
>> When I was in high school I was taught, or I read, that it's bad to turn
>> the steering wheel when the car is not moving.Â*Â* It's hard on the front
>> tires, wears out the tread, and one should be moving the car at least a
>> little when turning the wheel.Â*Â* Did they say that?Â* Do they still?
>>

>
> More importantly, it's hard on the steering linkage, which tends to be a
> lot more expensive to replace.


If it was so hard on the steering, manufacturers would never have fitted
power steering to cars.
>
> Mind you, with modern power steering, clueless drivers, and longer
> warranties, manufacturers have probably beefed up that part of the
> mechanism.


Nope, the parts were sufficiently strong enough before the advent of
power steering.
>
> Still, when you trust your life to a machine, treating it well seems
> like a no-brainer.
>
> Sylvia.


All driving instructors (should) tell their students to roll the car
fore or aft slightly when turning the steering. It is amazing just how
much of a difference that makes to steering effort. What you are
effectively doing is transferring the energy to the tread blocks and
they are sufficiently flexible enough to absorb the energy involved.
After all, it's the tread blocks that are giving you slip angles at
higher road speeds. https://en.wikipedia.org/wiki/Slip_angle



--

Xeno


Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)
  #13  
Old May 13th 19, 02:46 PM posted to sci.math,sci.physics,rec.autos.tech
SergIo
external usenet poster
 
Posts: 2
Default Rubbing the tire on the road, is it really mathematically simple?

On 5/13/2019 8:27 AM, Xeno wrote:
> On 12/5/19 3:14 pm, Sylvia Else wrote:
>> On 12/05/2019 7:13 am, micky wrote:
>>> When I was in high school I was taught, or I read, that it's bad to turn
>>> the steering wheel when the car is not moving.Â*Â* It's hard on the front
>>> tires, wears out the tread, and one should be moving the car at least a
>>> little when turning the wheel.Â*Â* Did they say that?Â* Do they still?
>>>

>>
>> More importantly, it's hard on the steering linkage, which tends to be
>> a lot more expensive to replace.

>
> If it was so hard on the steering, manufacturers would never have fitted
> power steering to cars.


power steering is force multiplier, makes it easier to steer.

but along the way companies cheapend out the power steering, mostly the
pump, and it is less reliable, in some cars not replaceable if it
breaks, you can only get another from a junk yard and put it in, but it
is just as bad, plastic tanks that crack....

>>
>> Mind you, with modern power steering, clueless drivers, and longer
>> warranties, manufacturers have probably beefed up that part of the
>> mechanism.

>
> Nope, the parts were sufficiently strong enough before the advent of
> power steering.


true, I think all cars have power steering now, know of any that do not ?

>>
>> Still, when you trust your life to a machine, treating it well seems
>> like a no-brainer.
>>
>> Sylvia.

>
> All driving instructors (should) tell their students to roll the car
> fore or aft slightly when turning the steering. It is amazing just how
> much of a difference that makes to steering effort. What you are
> effectively doing is transferring the energy to the tread blocks and
> they are sufficiently flexible enough to absorb the energy involved.
> After all, it's the tread blocks that are giving you slip angles at
> higher road speeds.Â* https://en.wikipedia.org/wiki/Slip_angle
>
>
>


  #14  
Old May 13th 19, 03:05 PM posted to sci.math,sci.physics,rec.autos.tech
Xeno
external usenet poster
 
Posts: 363
Default Rubbing the tire on the road, is it really mathematically simple?

On 12/5/19 7:13 am, micky wrote:
> When I was in high school I was taught, or I read, that it's bad to turn
> the steering wheel when the car is not moving. It's hard on the front
> tires, wears out the tread, and one should be moving the car at least a
> little when turning the wheel. Did they say that? Do they still?
>
> I've been thinking about this and now I have doubts.
>
> Seems to me any extra wear on the tread because of turning the direction
> in which the tires point will be the same whether the car is moving or
> still. It's harder to relate to the sliding motion of the tire on the
> road surface when the car is moving, but it's clear when the car is
> still. That seems to me to be the difference, but the vectors that
> indicate rubbing seem the same either way.


When you are driving along the road, the tread stays gripped to the road
surface. If it didn't you would be in deep **** at the first corner. At
speed, any speed, the tread blocks are sufficiently flexible to allow
the wheels a small change in steering angle yet still remain gripping
the road surface. https://en.wikipedia.org/wiki/Slip_angle

>
> I included the math group first because it seems like they would have
> opinions.
>

Rather than opinions, I'll direct you to relevant texts on the topic;

Tires, Suspension and Handling, Second Edition
John C Dickson
https://www.sae.org/publications/books/content/R-168

This text covers the subject in more detail;

Steering Handbook
Editors: Manfred Harrer, Peter Pfeffer
https://www.springer.com/gp/book/9783319054483

Chapters 1 through 5 should more than adequately cover your needs.

If you really want to delve heavily into the mathematics of it all, then
this book should do it;

The Automotive Chassis
Engineering Principles, 2nd Edition
J Reimpell, H Stoll, J.W. Betzler
https://www.abebooks.com/97807680065...0768006570/plp


The above cover steering, including tyres, from an engineering
perspective and I suspect that's what you're after. The Along the way
you'll get a good grounding on all the effects of steering geometry.



--

Xeno


Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)
  #15  
Old May 13th 19, 03:10 PM posted to sci.math,sci.physics,rec.autos.tech
Xeno
external usenet poster
 
Posts: 363
Default Rubbing the tire on the road, is it really mathematically simple?

On 13/5/19 11:46 pm, sergIo wrote:
> On 5/13/2019 8:27 AM, Xeno wrote:
>> On 12/5/19 3:14 pm, Sylvia Else wrote:
>>> On 12/05/2019 7:13 am, micky wrote:
>>>> When I was in high school I was taught, or I read, that it's bad to turn
>>>> the steering wheel when the car is not moving.Â*Â* It's hard on the front
>>>> tires, wears out the tread, and one should be moving the car at least a
>>>> little when turning the wheel.Â*Â* Did they say that?Â* Do they still?
>>>>
>>>
>>> More importantly, it's hard on the steering linkage, which tends to be
>>> a lot more expensive to replace.

>>
>> If it was so hard on the steering, manufacturers would never have fitted
>> power steering to cars.

>
> power steering is force multiplier, makes it easier to steer.
>
> but along the way companies cheapend out the power steering, mostly the
> pump, and it is less reliable, in some cars not replaceable if it
> breaks, you can only get another from a junk yard and put it in, but it
> is just as bad, plastic tanks that crack....


Plastics are the *new vanguards of planned obsolecence*.
>
>>>
>>> Mind you, with modern power steering, clueless drivers, and longer
>>> warranties, manufacturers have probably beefed up that part of the
>>> mechanism.

>>
>> Nope, the parts were sufficiently strong enough before the advent of
>> power steering.

>
> true, I think all cars have power steering now, know of any that do not ?


Wide tyres, powerful engines and front wheel drive, with attendant
torque steer, have guaranteed it.
>
>>>
>>> Still, when you trust your life to a machine, treating it well seems
>>> like a no-brainer.
>>>
>>> Sylvia.

>>
>> All driving instructors (should) tell their students to roll the car
>> fore or aft slightly when turning the steering. It is amazing just how
>> much of a difference that makes to steering effort. What you are
>> effectively doing is transferring the energy to the tread blocks and
>> they are sufficiently flexible enough to absorb the energy involved.
>> After all, it's the tread blocks that are giving you slip angles at
>> higher road speeds.Â* https://en.wikipedia.org/wiki/Slip_angle
>>
>>
>>

>



--

Xeno


Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)
  #16  
Old May 13th 19, 06:03 PM posted to rec.autos.tech
Sanity Clause[_3_]
external usenet poster
 
Posts: 11
Default Rubbing the tire on the road, is it really mathematically simple?

dsi1 wrote:
>
> My method of avoiding excessive tire slippage when parallel parked is to use a floor jack to lift the front tires off the ground and swing the entire front end clear of the car in front. This saves excessive strain on the tires, steering linkage, the steering rack, and the power steering pump. Never having to replace the entire front suspension is pretty much a no-brainer. Thanks to years of practice, I can pull out of a space in only 2 minutes!


Too slow. Go electric built-in.
How to park in tight spaces - https://www.youtube.com/watch?v=WTg2DJNtk3A

Faster way to get out of tight spaces -
https://www.youtube.com/watch?v=-s3xYaqWcAE



  #17  
Old May 13th 19, 07:54 PM posted to rec.autos.tech
[email protected]
external usenet poster
 
Posts: 128
Default Rubbing the tire on the road, is it really mathematically simple?

On Monday, May 13, 2019 at 9:10:05 AM UTC-5, Xeno wrote:
> On 13/5/19 11:46 pm, sergIo wrote:
> > On 5/13/2019 8:27 AM, Xeno wrote:
> >> On 12/5/19 3:14 pm, Sylvia Else wrote:
> >>> On 12/05/2019 7:13 am, micky wrote:
> >>>> When I was in high school I was taught, or I read, that it's bad to turn
> >>>> the steering wheel when the car is not moving.Â*Â* It's hard on the front
> >>>> tires, wears out the tread, and one should be moving the car at least a
> >>>> little when turning the wheel.Â*Â* Did they say that?Â* Do they still?
> >>>>
> >>>
> >>> More importantly, it's hard on the steering linkage, which tends to be
> >>> a lot more expensive to replace.
> >>
> >> If it was so hard on the steering, manufacturers would never have fitted
> >> power steering to cars.

> >
> > power steering is force multiplier, makes it easier to steer.
> >
> > but along the way companies cheapend out the power steering, mostly the
> > pump, and it is less reliable, in some cars not replaceable if it
> > breaks, you can only get another from a junk yard and put it in, but it
> > is just as bad, plastic tanks that crack....

>
> Plastics are the *new vanguards of planned obsolecence*.
> >
> >>>
> >>> Mind you, with modern power steering, clueless drivers, and longer
> >>> warranties, manufacturers have probably beefed up that part of the
> >>> mechanism.
> >>
> >> Nope, the parts were sufficiently strong enough before the advent of
> >> power steering.

> >
> > true, I think all cars have power steering now, know of any that do not ?

>
> Wide tyres, powerful engines and front wheel drive, with attendant
> torque steer, have guaranteed it.
> >
> >>>
> >>> Still, when you trust your life to a machine, treating it well seems
> >>> like a no-brainer.
> >>>
> >>> Sylvia.
> >>
> >> All driving instructors (should) tell their students to roll the car
> >> fore or aft slightly when turning the steering. It is amazing just how
> >> much of a difference that makes to steering effort. What you are
> >> effectively doing is transferring the energy to the tread blocks and
> >> they are sufficiently flexible enough to absorb the energy involved.
> >> After all, it's the tread blocks that are giving you slip angles at
> >> higher road speeds.Â* https://en.wikipedia.org/wiki/Slip_angle
> >>
> >>
> >>

> >

>
>
> --
>
> Xeno
>
>
> Nothing astonishes Noddy so much as common sense and plain dealing.
> (with apologies to Ralph Waldo Emerson)


Japanese slider cars. Yonaguni, Okinawa, Japan received 14.4 inches of rain in 6 hours. https://yonews.org Good for sliding cars.
  #18  
Old May 26th 19, 09:10 PM posted to sci.math,sci.physics,rec.autos.tech
micky
external usenet poster
 
Posts: 383
Default Rubbing the tire on the road, is it really mathematically simple?


I just got home and I have time now to read this detailed answer
carefully, but it's been two weeks and many may miss my answer now, let
alone if I wait longer, so this reply just addresses non-technical
points.

To comment on the technical points of this and a post by Xeno, I have to
read the links. That will take a few more days.

In sci.math, on Sun, 12 May 2019 01:14:45 +0200, Thomas 'PointedEars'
Lahn > wrote:

>micky amok-crossposted to sci.math, sci.physics, and rec.autos.tech:
>^^^^^
>Please post here using your real name.
>
>> When I was in high school I was taught, or I read, that it's bad to turn
>> the steering wheel when the car is not moving. It's hard on the front
>> tires, wears out the tread, and one should be moving the car at least a
>> little when turning the wheel. Did they say that? Do they still?

>
>Yes, of course. However, this is just a rule of thumb; the amount of wear
>depends on the surface and the type of tread. For example, the wear from
>turning a still tire on ice or snow is negligibly small compared to the
>turning on asphalt.


Sure, but I was figuring "all things being equal".

>> I've been thinking about this and now I have doubts.

>
>You have not thought this through.
>
>> Seems to me any extra wear on the tread because of turning the direction
>> in which the tires point will be the same whether the car is moving or
>> still.

>
>It is not. When the car is moving relative to the ground surface (road),
>and the wheel and tire are rotating the tire’s tread is experiencing mostly


"Mostly rolling", but if you integrate the sliding** portion over the
time the wheels are being turned, I think the amount will equal no
matter whether the car is going quickly, slowly, or not at all.

**kinetic friction you call it.

>rolling resistance/friction/drag with the road. When the car is at rest
>relative to the road, if the wheel is turned, the tread is experiencing
>mostly kinetic friction with the road.


Maybe entirely.

>The magnitude of the friction (a force) between two surfaces is calculated
>as the friction coefficient (commonly: µ, mu) for the contact of the two
>surfaces for the respective situation times the magnitude of the normal
>force F_n on the body with significantly less mass (lighter body):
>
> F_f = µ F_n,
>
>whereas
>
> F_n = F_g cos ? = m g cos ?
>
>is the force with which a body is pressed against the ground surface by
>gravity (actually the force that the ground surface must exert on the
>lighter body to prevent it from continuing to fall freely towards the center
>of energy–momentum of the heavier body, e.g. the center-of-mass of Earth).
>
>? is then the angle of the ground surface to the tangent surface of the
>heavier body:
>
> .
> :`.
> : `.
> : `.
> : `. m
> : `* cos(?) = F_n/F_g
> : F_n .^:`. F_n = F_g cos(?)
> : .' ?: `.
> : .' : `.
> : `. : F_g `.
> : `. : `.
> : `.: `. ^
> :__ v `. : n __
> : | ?`. : |PE
> '--------------------------`----'--
>
>(? = 0 ? F_n = F_g cos(0) = F_g × 1 = F_g as expected, so this works.)
>
>The coefficient of rolling resistance is generally much smaller than that of
>kinetic friction – which is why the wheel was invented in the first place.
>For example, the coefficient of kinetic friction for car tire rubber on
>concrete is 0.6 to 0.85, while the coefficient of rolling resistance is only
>0.01 to 0.015.
>
><https://en.wikipedia.org/wiki/Friction#Kinetic_friction>
><https://en.wikipedia.org/wiki/Rolling_resistance>
>
>For a car that has an average mass of 1 metric ton, on a horizontal road
>that makes a difference of friction of at least
>
> F_fs = µ_s m g = 0.6 × m g = 0.6 × 1'000 kg × 9.82 m/s² ? 5'892 N
>
>to
>
> F_fr = µ_r m g = 0.01 × 1'000 kg × 9.82 m/s² ? 98.2 N,
>
>i.e. at least 60:1. The greater the friction, the greater the wear. So,
>roughly speaking, turning a still tire wears it off 60 times more than
>turning it while driving, which means that its lifetime is reduced to 1/60
>of its normal lifetime if this would be done continuously.
>
>> It's harder to relate to the sliding motion of the tire on the
>> road surface when the car is moving,

>
>A tire is usually *rolling*, NOT sliding, on the road surface.
>
> [If it would be sliding, then the respective vehicle would be out of
> control. One possibility for this condition is aquaplaning: the tire
> is sliding on the water on the road instead of rolling in proper
> contact with the road. Tires with a pronounced profile and suitable
> tread pattern reduce or avoid aquaplaning as the water can be displaced
> into the tread pattern so that the tire keeps in contact with the
> road.
>
> <https://en.wikipedia.org/wiki/Aquaplaning#Prevention_by_the_driver>]
>
>> but it's clear when the car is still. That seems to me to be the
>> difference, but the vectors that indicate rubbing seem the same either way.

>
>Most certainly they are not. In the rolling case there is an additional
>non-zero force vector in the direction of the wheel’s axial rotation:
>
> ___ ___
> : : : :
> : .-:----> F_fk : -------> F_fk = F_res
> ^ : : :
> F_fr : : : :
> : : :
> =:=*=:= =:=*=:=
> : : : :
> : : : :
> : : : :
> : : : :
> :___: :___:
>
> rolling, at rest,
> turning left turning left
>
> (friction is always opposite to the direction of motion)
>
>Since the tread profile is optimized for the wheel rolling in the direction
>of axial rotation, NOT sliding, sidewards sliding of the tire at rest is
>detrimental to the lifetime of the tire and quality of the tread,
>particularly when the vehicle has a great mass and it is done on a
>horizontal road (as then the friction is greater; see above). Also, one can
>imagine that the greater torque required to turn a still wheel (to work
>against the greater friction) produces additional stress and wear for the
>steering.
>
>> I included the math group first because it seems like they would have
>> opinions.

>
>Please do not do that again.


Sorry, I can't abide by your request. People from the math group red my
first question and they are interested in all the answers. Especially
since you put so much effort into this one, I'd think you'd want anyone
who might be interested to see it.

Plus I think it's a violation of Usenetiquette to drop groups. Were
that done in 2 or 3 of the 3 groups I posted to, I'd have to read all 3
groups to see all the answers.

>
> “No article in the world is relevant for more than
> a few newsgroups. If World War ? is announced,
> it will be announced in news.announce.important.”
>
> –attributed to Peter da Silva


I dont' know who he is, but even if he's right, I only posted to 3
newsgroups.

>F’up2 sci.physics


  #19  
Old May 26th 19, 10:01 PM posted to sci.physics,sci.math,rec.autos.tech
Odd Bodkin
external usenet poster
 
Posts: 1
Default Rubbing the tire on the road, is it really mathematically simple?

micky > wrote:
>
> I just got home and I have time now to read this detailed answer
> carefully, but it's been two weeks and many may miss my answer now, let
> alone if I wait longer, so this reply just addresses non-technical
> points.
>
> To comment on the technical points of this and a post by Xeno, I have to
> read the links. That will take a few more days.
>
> In sci.math, on Sun, 12 May 2019 01:14:45 +0200, Thomas 'PointedEars'
> Lahn > wrote:
>
>> micky amok-crossposted to sci.math, sci.physics, and rec.autos.tech:
>> ^^^^^
>> Please post here using your real name.
>>
>>> When I was in high school I was taught, or I read, that it's bad to turn
>>> the steering wheel when the car is not moving. It's hard on the front
>>> tires, wears out the tread, and one should be moving the car at least a
>>> little when turning the wheel. Did they say that? Do they still?

>>
>> Yes, of course. However, this is just a rule of thumb; the amount of wear
>> depends on the surface and the type of tread. For example, the wear from
>> turning a still tire on ice or snow is negligibly small compared to the
>> turning on asphalt.

>
> Sure, but I was figuring "all things being equal".
>
>>> I've been thinking about this and now I have doubts.

>>
>> You have not thought this through.
>>
>>> Seems to me any extra wear on the tread because of turning the direction
>>> in which the tires point will be the same whether the car is moving or
>>> still.

>>
>> It is not. When the car is moving relative to the ground surface (road),
>> and the wheel and tire are rotating the tireÂ’s tread is experiencing mostly

>
> "Mostly rolling", but if you integrate the sliding** portion over the
> time the wheels are being turned, I think the amount will equal no
> matter whether the car is going quickly, slowly, or not at all.
>
> **kinetic friction you call it.


The point is that when you steer the car while rolling, there is actually
no sliding involved, or at least quite a bit less. This answer would be
different if you were talking about a metal or wooden wheel. But when you
turn a wheel with a rubber tire, the rubber tire twists. One way you can
look at it is that the tread of the tire that is in contact with the
asphalt is still aligned straight ahead, while the tread in front of that
patch is angled to the left. There is indeed heating of the tire that comes
from such distortion if the rubber, but this is quite distinct from the
tire tread sliding against asphalt, which it doesn’t do.

A simple thing to notice is the sound your tire makes when you lock the
brakes at low speed, which IS a case of kinetic friction. Do the tires make
that noise when you make a rolling turn? Try it.

>
>> rolling resistance/friction/drag with the road. When the car is at rest
>> relative to the road, if the wheel is turned, the tread is experiencing
>> mostly kinetic friction with the road.

>
> Maybe entirely.
>
>> The magnitude of the friction (a force) between two surfaces is calculated
>> as the friction coefficient (commonly: µ, mu) for the contact of the two
>> surfaces for the respective situation times the magnitude of the normal
>> force F_n on the body with significantly less mass (lighter body):
>>
>> F_f = µ F_n,
>>
>> whereas
>>
>> F_n = F_g cos ? = m g cos ?
>>
>> is the force with which a body is pressed against the ground surface by
>> gravity (actually the force that the ground surface must exert on the
>> lighter body to prevent it from continuing to fall freely towards the center
>> of energy–momentum of the heavier body, e.g. the center-of-mass of Earth).
>>
>> ? is then the angle of the ground surface to the tangent surface of the
>> heavier body:
>>
>> .
>> :`.
>>> `.
>>> `.
>>> `. m
>>> `* cos(?) = F_n/F_g
>>> F_n .^:`. F_n = F_g cos(?)
>>> .' ?: `.
>>> .' : `.
>>> `. : F_g `.
>>> `. : `.
>>> `.: `. ^

>> :__ v `. : n __
>>> | ?`. : |PE

>> '--------------------------`----'--
>>
>> (? = 0 ? F_n = F_g cos(0) = F_g × 1 = F_g as expected, so this works.)
>>
>> The coefficient of rolling resistance is generally much smaller than that of
>> kinetic friction – which is why the wheel was invented in the first place.
>> For example, the coefficient of kinetic friction for car tire rubber on
>> concrete is 0.6 to 0.85, while the coefficient of rolling resistance is only
>> 0.01 to 0.015.
>>
>> <https://en.wikipedia.org/wiki/Friction#Kinetic_friction>
>> <https://en.wikipedia.org/wiki/Rolling_resistance>
>>
>> For a car that has an average mass of 1 metric ton, on a horizontal road
>> that makes a difference of friction of at least
>>
>> F_fs = µ_s m g = 0.6 × m g = 0.6 × 1'000 kg × 9.82 m/s² ? 5'892 N
>>
>> to
>>
>> F_fr = µ_r m g = 0.01 × 1'000 kg × 9.82 m/s² ? 98.2 N,
>>
>> i.e. at least 60:1. The greater the friction, the greater the wear. So,
>> roughly speaking, turning a still tire wears it off 60 times more than
>> turning it while driving, which means that its lifetime is reduced to 1/60
>> of its normal lifetime if this would be done continuously.
>>
>>> It's harder to relate to the sliding motion of the tire on the
>>> road surface when the car is moving,

>>
>> A tire is usually *rolling*, NOT sliding, on the road surface.
>>
>> [If it would be sliding, then the respective vehicle would be out of
>> control. One possibility for this condition is aquaplaning: the tire
>> is sliding on the water on the road instead of rolling in proper
>> contact with the road. Tires with a pronounced profile and suitable
>> tread pattern reduce or avoid aquaplaning as the water can be displaced
>> into the tread pattern so that the tire keeps in contact with the
>> road.
>>
>> <https://en.wikipedia.org/wiki/Aquaplaning#Prevention_by_the_driver>]
>>
>>> but it's clear when the car is still. That seems to me to be the
>>> difference, but the vectors that indicate rubbing seem the same either way.

>>
>> Most certainly they are not. In the rolling case there is an additional
>> non-zero force vector in the direction of the wheelÂ’s axial rotation:
>>
>> ___ ___
>>>>> :
>>> .-:----> F_fk : -------> F_fk = F_res

>> ^ : : :
>> F_fr : : : :
>>>> :

>> =:=*=:= =:=*=:=
>>>>> :
>>>>> :
>>>>> :
>>>>> :

>> :___: :___:
>>
>> rolling, at rest,
>> turning left turning left
>>
>> (friction is always opposite to the direction of motion)
>>
>> Since the tread profile is optimized for the wheel rolling in the direction
>> of axial rotation, NOT sliding, sidewards sliding of the tire at rest is
>> detrimental to the lifetime of the tire and quality of the tread,
>> particularly when the vehicle has a great mass and it is done on a
>> horizontal road (as then the friction is greater; see above). Also, one can
>> imagine that the greater torque required to turn a still wheel (to work
>> against the greater friction) produces additional stress and wear for the
>> steering.
>>
>>> I included the math group first because it seems like they would have
>>> opinions.

>>
>> Please do not do that again.

>
> Sorry, I can't abide by your request. People from the math group red my
> first question and they are interested in all the answers. Especially
> since you put so much effort into this one, I'd think you'd want anyone
> who might be interested to see it.
>
> Plus I think it's a violation of Usenetiquette to drop groups. Were
> that done in 2 or 3 of the 3 groups I posted to, I'd have to read all 3
> groups to see all the answers.
>
>>
>> “No article in the world is relevant for more than
>> a few newsgroups. If World War ? is announced,
>> it will be announced in news.announce.important.”
>>
>> –attributed to Peter da Silva

>
> I dont' know who he is, but even if he's right, I only posted to 3
> newsgroups.
>
>> FÂ’up2 sci.physics

>
>




--
Odd Bodkin — Maker of fine toys, tools, tables
  #20  
Old May 27th 19, 09:01 PM posted to sci.math,sci.physics,rec.autos.tech
micky
external usenet poster
 
Posts: 383
Default Rubbing the tire on the road, is it really mathematically simple?

In sci.math, on Sun, 12 May 2019 01:26:41 +0200, Thomas 'PointedEars'
Lahn > wrote:

>Paul in Houston TX amok-crossposted:
>^^^^^^^^^^^^^^^^^^
>Please post here using your real name, “Paul in Houston TX” #74656.
>
>> I would think that total tire wear would be the same but wear per unit
>> area would be different.


Hmm. That sounds right.

>What is the basis for your assumption?


"Total tire wear would be the same". That's because of the law of
conservation of tire wear. Or, iow, one does't get something for
nothing so the wear would have to be the same. Or greater, but I don't
see why it would be greater.

When the car is not moving, all the wear would be in one place, but
surely when it's moving, the wear would be spread around the
circumference of the tire.

>F’up2 sci.physics



I put back the other two groups. Otherwise I, and everyone else, has to
read all three newsgroups to see all the answers.
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Local Tire Store 'Problems' With Road Force Balancer [email protected] Technology 4 August 26th 16 11:56 PM
What To Do When You Have Tire Blowout On The Road And How To Change A Flat Tire? news2feeds.com Technology 0 May 26th 07 04:20 PM
Tire rubbing problem Nevada Larry Ford Mustang 5 August 21st 06 05:14 PM
WJ road tire recommendation [email protected] Jeep 4 January 6th 06 10:57 PM
FS: Spare Super Swamper Off-Road Tire wheel and rack Must go ASAP! Hip 4x4 0 August 17th 04 03:21 PM


All times are GMT +1. The time now is 08:05 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 AutoBanter.
The comments are property of their posters.