OT? Weigh your car by checking tire pressure?

[Paul Hovnanian P.E.]

...

Ok, now you think about it some more. The pressure of the
tire surfaces against the road isn't uniform as long as the tire
remains effectively round.

Define "effectively round".

It's higher near the center of the
footprint, and close to zero at the edge where the tire is
barely touching the road.

Not really. That will result in uneven tread wear. The pressure across
the tire-road contact patch should be relatively uniform, dropping off
at the edges, of course.

Deflate the tire, and as the tire
squishes flatter, the pressure becomes more uniform over
an area that hasn't increased a great deal.

Take a look at the wear pattern of an under-inflated tire. Its greater
near the edges where sidewall stiffness has more effect and less in the
center. An over-inflated tire wears more in the middle due to
non-uniform loading.

 

[E Z Peaces]

Define "effectively round".


Not really. That will result in uneven tread wear. The pressure across
the tire-road contact patch should be relatively uniform, dropping off
at the edges, of course.



Take a look at the wear pattern of an under-inflated tire. Its greater
near the edges where sidewall stiffness has more effect and less in the
center. An over-inflated tire wears more in the middle due to
non-uniform loading.

Here are scans of tread pressure:
http://www.tekscan.com/industrial/tirescan-system.html

It seems that on a passenger car, the highest pressures are at the toe
and heel. I have an idea why. If the belt around the circumference
won't compress much and the tensile strength of the sidewalls limits its
movement away from the rim, the belt will be "too long" when the bottom
is flat against the ground. The belt that's off the ground will be
shoving the toe and heel against the ground, increasing the pressure on
the tread a little above the psi to which the tire was inflated.

That might also be a reason underinflated radials wear on the shoulders.

 

[ChairmanOfTheBored]

Pretty emotional response for someone who doesn't care about what others
say.....

The TerrellTard spends a lot of his time attacking me.

Therefore I spend the time I use making responses to his bullshit doing
so in as nasty a way as possible.

Don't think so? You can **** off too, then.

 

[ChairmanOfTheBored]

They fake those post because they know that you don't have the guts
to say how you really feel about them. If you didn't hold in your
feelings so much, you could save them a hell of a lot of work.


They love you, no matter how much they 'bore' you.

You're a goddamned retard. Nearly every post you make proves it.

 

[ChairmanOfTheBored]

That's not entirely true. In fact, the footprint would increase, and
the pressure could never reach zero, unless you used a vacuum pump.
0 PSIG is equal to approx. 14.7 PSIA, you know. ;-)

Except that a relative value was given, and it also would depend on
altitude.

It certainly wouldn't be very accurate, however. ;-)

Like your assertions.

 

[Michael A. Terrell]

You're a goddamned retard. Nearly every post you make proves it.

Sigh. Like you would know 'anything' about anyone else being
retarded, Morph Meister. Your second grade insults and constant errors
in your posts prove that you've been brain dead for years. You are just
too stupid to finish the job, and drop dead.

You don't even have to post for people to see how much brain rot
you've suffered. There is nothing on Usenet that is any more boring
than you and your kook minions. Grow up and get a life, or take the
easy way out by investing in a single bullet, and play Russian Roulette
till you 'win'.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Michael A. Terrell]

The Morph Meister spends a lot of his time attacking people.

Very true, Morph Meister. The first honest thing that you have ever
said.

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[CBFalconer]

ChairmanOfTheBored wrote:
.... snip ...


Sigh. Like you would know 'anything' about anyone else being
retarded, Morph Meister. Your second grade insults and constant
errors in your posts prove that you've been brain dead for years.
You are just too stupid to finish the job, and drop dead.

--
+-------------------+ .:\:\:/:/:.
| PLEASE DO NOT F :.:\:\:/:/:.:
| FEED THE TROLLS | :=.' - - '.=:
| | '=(\ 9 9 /)='
| Thank you, | ( (_) )
| Management | /`-vvv-'\
+-------------------+ / \
| | @@@ / /|,,,,,|\ \
| | @@@ /_// /^\ \\_\
@x@@x@ | | |/ WW( ( ) )WW
\||||/ | | \| __\,,\ /,,/__
\||/ | | | jgs (______Y______)
/\/\/\/\/\/\/\/\//\/\\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
==============================================================

fix (vb.): 1. to paper over, obscure, hide from public view; 2.
to work around, in a way that produces unintended consequences
that are worse than the original problem. Usage: "Windows ME
fixes many of the shortcomings of Windows 98 SE". - Hutchinson

 

[*]

You're a goddamned retard. Nearly every post you make proves it.

He must be one of those "Idiot Savants" then, because he is playing YOU
like a tightly strung violin...........

 

[*]

I think tread flexing may matter more than sidewall flexing, and taller
wheels have less of it.

Suppose your tire has a 10" radius and, due to sidewall flexing, the
distance from the center to the pavement is 9". The contact patch
should be 8.7" long, and the tread must flex 26 degrees at the front and
back of the patch.

I'd love to see the math on that one......

On a 4800 pound car with equally distributed wheel weights (1200 pounds at
each wheel) at 30 p.s.i. tire pressure, you would need a contact patch
that is 40 in² to support that weight.

In order to have an 8.7" long contact patch at 30 p.s.i., you would have a
contact patch that is only 4.59" wide.

Most of today's tire treads are much wider than that.....

I think you are confusing terms.......

Contact patch LENGTH is measured front-to-back - parallel with the tread.

Contact patch WIDTH is measured side-to-side - across the tread surface.

 

[E Z Peaces]

I'd love to see the math on that one......

On a 4800 pound car with equally distributed wheel weights (1200 pounds at
each wheel) at 30 p.s.i. tire pressure, you would need a contact patch
that is 40 in² to support that weight.

In order to have an 8.7" long contact patch at 30 p.s.i., you would have a
contact patch that is only 4.59" wide.

Most of today's tire treads are much wider than that.....

I think you are confusing terms.......

Contact patch LENGTH is measured front-to-back - parallel with the tread.

Contact patch WIDTH is measured side-to-side - across the tread surface.

I'll bet you've never seen a car with a 20" tire radius, either. It was
hypothetical. On my gravel drive, I've never tried to measure the
length of my contact patches.

I have read that tread flexing causes rolling resistance, but in a car
with proper inflation, the flexing must be much less than 26 degrees. I
have encountered something possibly more severe hauling gravel in a
pickup. When the tires sagged badly I needed engine power to keep
moving even downhill.

 

[Anthony Buckland]

Define "effectively round".


Not really. That will result in uneven tread wear. The pressure across
the tire-road contact patch should be relatively uniform, dropping off
at the edges, of course.
...

My bad, I wasn't specific about "edge".
I meant the front and back edges of the footprint,
not the side edges. By "effectively round" I
meant the appearance of the tire from the side,
not its appearance from the front or back.

I agree, a properly inflated tire should look
essentially flat from side to side where it
touches the road as seen from the front
or back (_) ; but seen from the side, there
will be regions at the front and back of the
footprint where the tire just touches the road,
tapering towards the full-contact region.
This will be more pronounced if the tire is
over-inflated, and will approach triviality
as the tire approaches squishing flat.

When a tire looks like (_) from the side,
you're in trouble.

 

[ChairmanOfTheBored]

He must be one of those "Idiot Savants" then, because he is playing YOU
like a tightly strung violin...........

You're a goddamned idiot.

 

[Richard Heathfield]

Anthony Buckland said:

When a tire looks like (_) from the side,
you're in trouble.

But not very much trouble. After all, it's only the bottom bit that's
broken - the rest of the tyre is fine.

 

[*]

You're a goddamned idiot.

Something "clicked" for me when I read your response.....

Your "clever" retort has convinced me to turn my life around....

I will now seek truth and justice......not the REAL truth and justice, of
course, but the so-called "truth and justice" of those who believe they
alone are the sole arbiters of truth and justice - such as you.....

Your absolute minimalist use of the English language to get your point
across has convinced me that you are, indeed, a shining star - a "Point of
Light" if you will - that I must follow and emulate.

I will abandon my old philosophy that says, "Profanity is Audible
Ignorance" in order to to study the rational enhancement of my statements
through the liberal use of profanity.

Nothing - ABSOLUTELY NOTHING - portrays a well-rounded, sophisticated
education quite the way profanity does.

I will join PETA, Greenpeace, and other "worthy" organizations in order to
place myself above the great unwashed, and to position myself so I, too,
can confidently say,

"You're a goddamned idiot!!!"

and, a sincere, happy "**** You Too!!"