[GZG] GZG] AFV ground pressure ( was Re: New to the list, and 2

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I know tire pressure varies with temperature. As does the ability of the
tire to retain air usually. I live in Canada and get seasonal
demonstrations
of this.

2) My argument was that my car has had two differing types of the same
size
tires (same rolling diameter), both of which were Z-rated performance
radials, and the difference in recommended pressure was 28 psi to 35
psi.
That suggests about a 20% change in contact patch. I'm skeptical that
this
much of a change is made by that extra inflation. Tread pattern may well
impact this - one of the tires was a directional asymetric tire, the
other a
non-directional asymetric tire.

3) I have driven big trucks - 24' ban body 6-wheeler with a diesel. They
come with adequate mirrors and huge windscreens with wide visibility a
lot
of the time. I suspect most armoured vehicles have far more limited
viewpoint, which is why large armoured vehicles trying to manouver
through
tight urban spaces = damage to urban spaces. A Weasel or some of the
smaller
vehicles are a horse of a different colour.

And to all you 'higher pressure is good' folks: That's only one side of
the
story. Car tires  have optimal ranges based on traction requirements and
tread pattern and they also account for composition of the tire. If you
over
inflate for better gas mileage more than a few psi, you can end up
creating
a safety risk. Certainly, I never ran my Z-rated radials at overpressure
- I
bought Z-rated radials because I wanted the maximum stick that non-slick
drag tires could provide. When I was cornering at 180 kph plus, I wanted
every bit of stick to the track I could get. I never hit 240 kph, but I
had
an (unconfirmed) feeling that a Z-rated radial had more traction at all
speeds than a T-rated, for instance. That's why I bought Z.

Wear numbers like 220 suck for most people for replacement cycle (25K km
was
enough on some camaros and corvettes), but I had 260 and never had a
problem
with my tired - I'd get 65K-70K km on them. Mostly I didn't drive like I
was
on the way to a fire, just once and a while and then I wanted sticky. I
wonder what the wear number equivalent would be on tank rubber pads? I'm
guessing they're pretty hard, although less hard than asphalt and
probably
ablate thus saving the asphalt.

Running your tires under or overinflated beyond a few PSI is a bad idea
and
not terribly safe nor good for the tire. Buying fuel economy at the cost
of
ending up in a ditch during a snowstorm or wet road conditions isn't
smart.

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