Tire Size Question

In that case you remember this.

"Every object in a state of uniform motion tends to remain in that state of
motion unless an external force is applied to it."

This is Newton's First Law of Motion, which is essentially the same as
Galileo's concept of Inertia. You do not observe this principle in the case
of a vehicle, because rubber tires dissipate energy and there is friction in
the wheel bearings and air resistance. These three factors have nothing to
do with the mass of the wheel and tire combination. However, mountain bike
tires will be filled to a lower air pressure than road racing bike tires,
and so will dissipate more energy. The same holds for any larger than stock
tire on a Jeep.

I have not done or seen any formal study, but I think that the main factor
to consider when changing tires is to maintain the same rpm to road speed
ratio. This is what we call "gear inches" in the bicycle trade. How far do
you go for each turn of the crank? If you change this factor, you will
change available power and economy, in many cases for the worst.

Earle

"L.W. (ßill) Hughes III" > wrote in message
...
> I have, along with calculus.
> God Bless America, ßill O|||||||O
> http://www.billhughes.com/
>
> RoyJ wrote:
> >
> > Blather. Go take an introductory physics course.

Hi Earle,
Simple experiment for you is see how fast you may drive your jeep
in a safe place, then do the same test after filling your tires with
water. Didn't you have any friend that converted their bugs to Manx,
then put fat tires on their reversed VW rims. My original experiment was
a switched from 400 X 19 motorcycle tires to 600 X 15, and went from a
top speed of 65 mph to about 50 as you may see no difference in outside
diameter: http://www.billhughes.com/36harley.jpg But I looked cool. ;-)
God Bless America, ßill O|||||||O


Earle Horton wrote:
>
> In that case you remember this.
>
> "Every object in a state of uniform motion tends to remain in that state of
> motion unless an external force is applied to it."
>
> This is Newton's First Law of Motion, which is essentially the same as
> Galileo's concept of Inertia. You do not observe this principle in the case
> of a vehicle, because rubber tires dissipate energy and there is friction in
> the wheel bearings and air resistance. These three factors have nothing to
> do with the mass of the wheel and tire combination. However, mountain bike
> tires will be filled to a lower air pressure than road racing bike tires,
> and so will dissipate more energy. The same holds for any larger than stock
> tire on a Jeep.
>
> I have not done or seen any formal study, but I think that the main factor
> to consider when changing tires is to maintain the same rpm to road speed
> ratio. This is what we call "gear inches" in the bicycle trade. How far do
> you go for each turn of the crank? If you change this factor, you will
> change available power and economy, in many cases for the worst.
>
> Earle

Awesome. Maybe I should have tried those 400x19s on my Bug. )

Earle

"L.W. (ßill) Hughes III" > wrote in message
...
> Hi Earle,
> Simple experiment for you is see how fast you may drive your jeep
> in a safe place, then do the same test after filling your tires with
> water. Didn't you have any friend that converted their bugs to Manx,
> then put fat tires on their reversed VW rims. My original experiment was
> a switched from 400 X 19 motorcycle tires to 600 X 15, and went from a
> top speed of 65 mph to about 50 as you may see no difference in outside
> diameter: http://www.billhughes.com/36harley.jpg But I looked cool. ;-)
> God Bless America, ßill O|||||||O
>
>
> Earle Horton wrote:
> >
> > In that case you remember this.
> >
> > "Every object in a state of uniform motion tends to remain in that state
of
> > motion unless an external force is applied to it."
> >
> > This is Newton's First Law of Motion, which is essentially the same as
> > Galileo's concept of Inertia. You do not observe this principle in the
case
> > of a vehicle, because rubber tires dissipate energy and there is
friction in
> > the wheel bearings and air resistance. These three factors have nothing
to
> > do with the mass of the wheel and tire combination. However, mountain
bike
> > tires will be filled to a lower air pressure than road racing bike
tires,
> > and so will dissipate more energy. The same holds for any larger than
stock
> > tire on a Jeep.
> >
> > I have not done or seen any formal study, but I think that the main
factor
> > to consider when changing tires is to maintain the same rpm to road
speed
> > ratio. This is what we call "gear inches" in the bicycle trade. How
far do
> > you go for each turn of the crank? If you change this factor, you will
> > change available power and economy, in many cases for the worst.
> >
> > Earle

"Earle Horton" > wrote in message =
news:1120505070.003960350be3a3afb69bfd2477673344@t eranews...
> I didn't invent perpetual motion. Newton did. The wheel would keep
> spinning forever, except for friction from the bearings, road and air. =
What
> keeps the Earth spinning? What happened to Stephen Cowell, anyway?
> I think that we need his expert opinion here.

Hey Earle.... here's my take... F =3D MA.

And forever is a *long* time... don't forget
about gravity waves, and magnetic effects.

And Bill... keep it up! I want to hear more
about gear ratios and E =3D mc^2!
__
Steve
..