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Re: Tire information

To: Ajhsys@aol.com
Subject: Re: Tire information
Date: Thu, 29 Aug 2002 15:24:09 -0400 (EDT)
Cc: david@vermonthardwoods.com, spridgets@autox.team.net
Allen:

I don't need a pyrometer for this one!

Underinflation is such a heat monster,
that any underinflation on airliner tires
requires immediate attention of some
sort. This is so important that the checking on tire inflation (where
not
monitored by gauges) is a daily maintenance inspection item.

I do not recall the numbers exactly but,
even 10% underinflation on one tire
allows for replacement of the other tire
on that "truck" supporting tires wherein
the underinflated one was found. Of course, "load" figures into this but
more
important is the >120+ speeds these tires
are subjected to during takeoffs and landings and the "squirm"
(distortion)
they go through when underinflated.

(Jets regularly exceed 160mph on takeoffs
so you can just imagine the heat caused
by "distortion" in terms of underinflation.)

And if both tires on that "truck" are found
underinflated by a certain number of 
pounds (not much though I do not recall
the exact number), both tires must be
replaced immediately. Underinflation
(in even minor pounds) is a "grounding"
item 'til properly attended to my a qualified mechanic and "signed off"
as
properly attended to "by the book".

Oddly enough, there are no penalties
whatsoever for overinflation, when found!

I guess "too much" equals a blown tire so
the "penalty" for this is obvious and thus requires no explanation as to
"proper 
corrective action"! :)

Auto applications:
Of course, tires can be safely inflated up
to the tire mfrs. maximum as noted
on the tire. Only penalty I know of for
overinflation beyond the VEHICLE's mfrs..
recommendation as used on the
road is a more firm ride and consequent
possible accelerated wear and tear on suspension components but when it
gets
"far out", you can usually see this in the form of "obvious" centerline
tire treadware
as compared to off-centerline treadware. 

And I can see where you might
lose a little blow-out protection hitting potholes and such due to
inflation beyond
the TIRE mfrs. specifcation so this is a
"no-go" limit in my book though by this
time "reasonable" ride quality has gone
by the wayside, I would think.

And, yeah. You want to see your gas
gauge drop and your car lose it's "pep"
along with "crisp" handling qualities and
grip....just underinflate vehicle mfrs. numbers by 10%.

I started at 22psi all around and am
now up to 26psi all around these days
(I have a 3/4 front bar and 175/70's on
5.5 Western "Minilite wannabe's" for
highway speed stability so the car is
a bit more of an "understeeror" than the "oversteeror" it was factory
equipped and thus "matching" front tire pressures rather
than less in front and more in rear gives
me more "neutral" handling).

Responsiveness and adhesion (grip)
have improved as has fuel mileage
(this is quite noticeable) while still
maintaining "reasonable" ride quality.

Will try 27 next week and see how this
"feels". At some point below the tire
mfrs. limit the ride quality will go to hell
and I'll have reached "my" limit accordingly.

Still, would be interesting to see pyrometer results! :)




Cap'n. Bob
    '60 :{)  

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