John,
In the 60's, the English tire and wheel sizes were in inches. Same as
ours. Although there are 25.4 mm/inch the wheel holes are 4 1/4 inches,
which is more like 107.95 mm (close to 108, rounded). So they are both
the same, if you are generally comparing wheels, but that does not
insure interchangeability. Luckily a quarter (or fifth) of a full circle
is the same no matter what system you are using, but such things as the
shape of the fastner connection to the wheel differs even with the same
standards, according to material and manufacturer's design.
A Shortened Version of Metric/English measurements:
There is the English system of measurements, (feet, inches, pounds), and
the Metric system (meters, centimeters, grams, kilograms, etc.) There
are also Standards. This would differentiate thread sizes, pitches,
depths, etc. Hence the "English" system can have Whitworth Bolts,
British Standard Bolts, and American Standard bolts, (all using inches)
as well as metric standards. The French, for instance, while using the
metric measurement system, earlier had their own unique bolt standards
that differed from other users of the metric measurement system. Hence
we had Standard metric and French metric bolts. I believe they have
since "unified" with the rest of the world, but the French are as
stubborn about their own "thing" as the English and the Americans.
We originally (Colonial days) used the "English System" for all our
measurements and standards, except money (after the Revolution). Our
original "American" monetary system is in units of 10, unlike the
British system of the time of pounds Sterling, Guineas, and schillings
of non-uniform intervals (like ounces, pounds, tons, feet, miles, etc.).
In the '50s we made a decision to nationally convert to the metric
system. As you can see, in our gas stations, super markets, liquor
stores, and cars, in the past 50 years our conversion has been very
slow.
The British also made a decision in the 50's to convert their
measurement system to the American standard in bolt sizes and standards,
and the metric system in currency and other goods. My '52 MG was full of
Whitworth bolts, requiring all special wrenches, sockets, taps, etc. All
bolts and nuts were imported and expensive. In '55 the cars had American
Standard fastners, for most stuff anyway. They also converted their
monetary system in the 70's. They used the same names, but divided them
in units of ten pence to the Pound, etc.
As we, they are still in the process of "converting". Many of the newer
cars are metric fasteners and other measurements. But in the 60's the
wheels were in inch standards.
Steve
--
Steve Laifman < One first kiss, >
B9472289 < one first love, and >
< one first win, is all >
< you get in this life. >
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