On Thu, 19 Jan 2006 07:30:24 -0600, "pkurtz2" <pkurtz2@cox.net> wrote:
>
>"Donut" <Donut@donut.net> wrote in message
>news:qc1ss1hls99an4e3bj7vd3rv6ic5bknr7g@4ax.com...
>> <top posting only because the auto student is>
>>
>> pkurtz,
>>
>> You are taking my examples *way* to literally. The reason I put
>> "normal driving conditions" in quotes is because I know there is no
>> such thing. How about average driving conditions? You know, that
>> state it which the vehicle is most often driven, that work for you?
>>
>> And when I referred to the three wheeler's, that was just another
>> example. So no, I wont be able to provide an identical car on the road
>> that you ask for. That was never my intention.
>>
>> Your argument still falls flat (no pun intended) to me.
>>
>> Harder tires (more inflation) equals better milage. Softer tires (less
>> inflation) equals worse milage. On average.
>>
>> To take it to some extremes. If you are driving on ice, then an under
>> inflated tire may increase your milage, as it provides a bigger
>> footprint, thus more traction, and without traction, you'd be
>> slipping. Of course your milage would be way worse than normal, but
>> you might be able get somewhere.
>>
>> On the other hand, if you are driving around in a place with little
>> precipitation, let alone the frozen kind, then a smaller footprint
>> would be good for your milage, and you *can* achieve this by
>> overinflating your tires.
>>
>> Not saying you should, mind you, you do have to factor in the altered
>> wear. Higher risk of puncture, and most likely shortened life of the
>> tires. And of course, less foot print equals less effective braking.
>>
>> I really just don't buy your argument that there would be significant
>> "slip". If your driving so fast that your vehicles tires are leaving
>> the road surface, then you aren't too worried about milage I'd guess
>> :) And even at moderate speeds, wouldn't inertia negate most of the
>> alleged "slip"?
>>
>> You used the word "exponentially" twice. As that is a mathematical
>> term, and you are an auto student, I suppose you could produce the
>> study or research that provides those numbers. You probably have
>> easier access than I would, so I'd appreciate seeing them, or links
>> to them.
>>
>> And if you're curious about the comment I put at the top of this post
>> in <>'s... http://en.wikipedia.org/wiki/Top-posting
>>
>> Don
>>
>Don,
>I appologize for top posting. I was unaware that it was a problem. The
>reason I do it that way is because I believe that it makes for an easier
>read, and if people are keeping current with the issue at hand, then it
>should not be a problem. I understand that some older generations of Usenet
>users won't like this, but I am not from that generation; however I try to
>have consideration for others, so I hope this is better.
> As to your comment about research being easier for me to come up with,
>well if I talk with my instructors then I am sure they can give me all the
>material I need. However, thanks to the WorldWideWeb, the information that
>you seek is at the hands of anyone with a computer. I just did a search five
>minutes ago on "gas mileage research" and it came up with about a thousand
>hits, and on the second one I looked at it actually said to follow
>manufacturers specifications for tire inflation, both quoting over-inflation
>and under-inflation as a source of fuel mileage loss. Keep in mind when
>doing web searches though, some common sense applies, and websites that end
>in .net or .org will tend to be the more trusted sites to have "good"
>information. The sites that end in .com are usually commercially based, and
>usually say things so that they can sell a product.
> As for producing the research I have read, I would have to go back 10yrs
>to compile everything. I have picked up various bits of information by
>reading material produced at shops that I have worked at, and through
>information produced in the classes I have taken.
> Also, as you said "taking my examples *way* to literally". I can only
>base my arguments on the "facts" which are given to me, and back up my
>arguments based on that. If you had come up with different, more real world,
>examples. Then I would have analyzed your argument and put it up against
>what I have been taught, and read over the years. Then I would have either
>agreed, or dismissed your argument and provided the information as to why.
>
>Here are some links that I picked up off the net for you. I realize that the
>first one ends in .com, but I think we can all trust CNN.. LOL
>http://money.cnn.com/2005/09/01/Auto...s_saving_test/
>
>http://en.wikipedia.org/wiki/Miles_per_gallon I had a feeling you would
>like this site, since you already used to inform me of my top posting.
>
>Hope these fine useful. I did notice that only first one said anything about
>over-inflating your tires. Anyway, have a good one, I have to get started on
>a head gasket job now..
Hi.
"Keep in mind that OVERINFLATION of your tires will actually HURT your
gas milage. The reason for this is because it changes the "footprint"
of the tire on the road, or the amount of tire you have in contact
with the road. Overinflating tires lessens how much tire is on the
road and contributes to slip. The more slip you have, the worse milage
you will get."
And
"So if you overinflate your tires, especially on the rear of a truck,
then you have increased the amount of slip exponentially."
These are your statements that I'm having trouble with. The first
statement I believe is false. If you want to say that overinflation
(and we still haven't said by how many psi) will cause poor handling
or poor tire wear or less effective braking, then fine. But you are
saying that it will hurt your gas milage, and I've not seen you
produce any evidence that corroborate that statement as fact. As a
matter of fact, the first link you sent sorta hurts your argument.
The second statement: While I'm very well versed in how to search the
web, I was fairly certain it would be hard to find the same research
you were using to cite those exponentially numbers. That's why I
asked you for it/them.
Remember, I'm only speaking to the issue of overinflated tires and
their effect on milage. You say it has a negative effect, ON MILAGE,
I say it doesn't.
Here's just a bit of stuff I found, one of them from you:
"Method: We drove the 55-mile test loop four times at 60 mph — twice
with tires at or above proper inflation. Once, we did the test with
the tires 5 psi below the pressure recommended by the manufacturer.
Since this produced very little difference we enlarged the gap and
under inflated the tires by 8 psi. We felt that it was important to
make sure the tires were inflated to the recommended level or above."
This from the link you sent.
http://money.cnn.edmunds.com/ownersh...cle.html#test5
------------
"Good inflation: Drivers waste millions of gallons of fuel each year
due to under-inflated tires. Maintaining optimum tire inflation is one
of the best things you can do to increase fuel economy. Inflate your
tires to the upper limit of the manufacturer's recommendations."
http://www.autosite.com/content/rese...cle/AID/135657
------------------
"Harder tires present less rolling resistance and improve gas mileage;
therefore, the Buick Estate Wagon outperformed our expectations based
on our regression model, which did not account for tire inflation
pressure. In our model Tire Pressure is a lurking variable, variable
that seems to help in predicting gas mileage but is not included in
the model."
http://score.kings.k12.ca.us/lessons...variables.html
-------------
"and keeping tires inflated to the maximum recommended pressure can
improve your gas mileage."
http://www.epa.gov/otaq/consumer/17-tips.pdf
---------------------
Me again.
I think you would be hard pressed to find anyone in an "official"
position suggesting that one "overinflate" one's tires past the
recommended maximum (due to liability), but they sure do seem to
suggest that you keep it as close as possible. But one wonders,
considering "Under-inflated tires can lower gas mileage by 0.4 percent
for every 1 psi drop in pressure of all four tires. Properly inflated
tires are safer and last longer." what every increase in psi (over the
recommended max) would bring?
Any way, I'm done with this discussion. Unless you can produce
evidence that shows moderately over inflated tires decrease gas
milage, we'll just have to agree to disagree.
Have fun with the Head Gasket :)
Don
>
<snip>
