bar to PSI for Steffi

[JHertzman@xxxxxxx]

I thought the conversion from bar to PSI for Jochen Tydecks' friend would be
the usual ho-hum look it up, but quickly found that a bar is a unit of
pressure equal to one million dynes per square centimeter, and that a dyne is
the unit of force which would give a free mass of one gram an acceleration of
one centimeter per second per second. That is as far as I got (it IS late) but
I would bet that the dyne is a unit introduced in the recent past along with
others intended to finesse the slight inaccuracies of the eighteenth century's
archaic Metric System definitions. I would be very surprised if the bar
differs markedly from the kilograms per square centimeter which Alfa has used
as long as I can remember (& still does), and which is the alternate
calibration shown on my fifties-era northern-European Draeger pressure guages.

If this is correct, Alfa accepts equivalences of:
1.5 kg/cm = 21 PSI
1.7 kg/cm = 24 PSI
1.8 kg/cm = 26 PSI
1.9 kg/cm = 28 PSI
2.0 kg/cm = 29 PSI
2.2 kg/cm = 31 PSI
2.5 kg/cm = 35 PSI

These allow some fudging, the 164 calls 35 PSI = 2.4 kg/cm and calls 31 PSI
2.1 kg/cm. It is also the source of the 28 PSI figure which does not exactly
split 26 & 29. Few of us get that precise with tire pressures.

If this doesn't fit the case probably her German car has a dealer near
Washington who could tell he how many PSI to use. 

Cordially, 

John H. 

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