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Re: [Phys-l] How "Compressive" is Defined.



"... personal injury lawyers who spanked service stations
formerly rash enough to offer air lines, where the gage could go out
of calibration, and injure motorists who overinflated."


So that's the reason; I thought it was the expense of an expensive compressor and its keepup including licensing and state mandated testing *. When gas stations were also garages, minimal marginal expense.

I foolishly have lost the photograph of the official in appearance sticker on a small box gas station compressor stating it's against CA law to charge for air next to the quarter slot. These things are useful only to the desperate. The volume ** is very low along w/ the low ultimate pressure. Last time I used one, it consumed three quarters to top off 25 => 35 psi (gauge).

* Whadau expect from a socialist?
** What's the correct physical term?

bc keeps a much quicker and more healthful hand pump in his mobile and, of course, a fancy digital display gauge.


Brian Whatcott wrote:

Sheldon Brown's bike enthusiast URL offers these inflation recommendations:

Tire widths are in millimeters, pressure recommendations in pounds
per square inch.

Wheel load 50 mm 37 mm 32 mm 28 mm 25 mm 23 mm 20 mm
100 lbs/50 kg 45 60 75 100 110 120 130
70 lbs/35 kg 35 50 65 80 90 100 110

Surprisingly high, you may think. It's not every service station air line
that can seriously exceed these numbers. Come to think of it,
it's not every service station that even offers an air line at all, thanks I
suppose to the personal injury lawyers who spanked service stations
formerly rash enough to offer air lines, where the gage could go out
of calibration, and injure motorists who overinflated.

Brian W



At 12:04 PM 11/13/2007, you wrote:

The airline concern is silly. I've certainly 'done' the experiment--blowing
out a tire by overpressurizing (using gas-station air to fill bike tires as
a kid). They just go 'poof' and leak the small volume of air contained. A
full 32 psi overpressure is not a huge percentage overpressure for bike
tires. I also am told, that car tires can usually withstand very large
overpressures as well.

Rick



Brian Whatcott Altus OK Eureka!
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