There was a discussion on the BWMA website concerning bike tires a few
months before I joined. I read some of the exchanges and went to the
websites. It turns out that when tires were sized in inches there was such
mess with the sizes that the ISO took over and made bicycle tire sizing an
ISO standard.
You may find this site of interest, as it explains how the "traditional
sizing system" in inches was a total mess and how the ISO (fully metric)
sizing system fixed the problem. With the metric sizing system you can't
just translate back and forth between the two. The inch numbers and the
metric numbers measure two different points on the tire or rim.
http://www.sheldonbrown.com/tire-sizing.html
As for the sales man, I would have asked him to do the calculations in
pounds, and when he couldn't do it then shame him by telling him its his
pounds that limits his ability to understand how these things work. There
is more to being a salesman then parroting inches and pounds and not having
a clue as to what it all means.
This guy might not need to know metric as the customers who come into the
shop, other then you, are as dumb as he is.
The BWMA has an award they give out to those who promote metrication and it
is called the metrickery award. Maybe we can come up with the imperial
dummy award and give it out to those who have been made dumb by using
imperial. This guy could be the first recipient.
Dan
----- Original Message -----
From: "Pierre Abbat" <[EMAIL PROTECTED]>
To: "U.S. Metric Association" <[email protected]>
Sent: Monday, 2005-10-17 22:36
Subject: [USMA:34937] Bicycle salesman can't handle bars
I went to the bike shop to buy a pump. They had several pumps with a gauge
with a psi dial and a bar dial. I stuck my thumb on the end and pumped
with
the other hand and got two bars. Then I figured that if the piston area is
10
cm², I can get just over eight bars by sitting on the handle. So I asked
the
salesman what the area is. He didn't know. I searched the pump and found
that
the diameter is 31 mm. "32² is 1024, 31² is 961, so it's seven and a
half", I
calculated aloud. (I work with computers, so 1024 is a lot more familiar
than
961.) That meant I could get almost the full eleven bars by sitting on it.
I
tried to explain, "I weigh 83, so I multiply by 9.8 to get newtons. A
pascal
is a newton per square meter. Ten square centimeters is 1/1000 square
meter,
so that's just over 800 kilopascals. 100 kPa is a bar, so that's just over
eight bars." The guy looked at me as if I were telling him baseball
scores.
"We measure in pounds," he answered. I asked him, "Haven't you heard
millibars - or hectopascals - or kilopascals - on the weather report?" He
didn't know what I was talking about.
The dimensions on the pump are all metric:
Bore:31mm
Stroke:540mm (actually that's the length of the tube, the stroke is 513)
Volume:410cc³ (sic)
The dimensions of tires are metric. The tires have their pressure
indicated in
bars or kilopascals or both. How does he expect to do his job if he
doesn't
know metric?
phma
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