Scott Dorsey wrote on 6 Dec 2016 16:45:21 -0500:

Assuming "Imperial" means "USA", that would mean I need a 32 TPI nut
somewhere between 0.271 inches and 0.305 inches in iD, but that doesn't
seem to be a standard size for a USA nut.

Sure isn't, that's deliberate.

I keep seeing this *mix* of metric and what they seem to call "Imperial",
(which I guess is the USA?).

Are we really that imperial?

Anyway, I'm confused about this mix of metric and US measurements. I
realize that car tires have both at the same time but for different things.

For example, the P250/50R18 designation is a mix of units for different
measurements
1. P = passenger
2. 250 = millimeters of tread width
3. 50 = percent width being the height in millimeters
4. R = radial
5. 18 = diameter in inches

So they mix letters, percents, millimeters, and inches but each one
designates a different measurement.

Is it the same with the mix of units on the Schrader valve threads?
The reason I ask is that there are only two measurements:
1. Nominal diameter (thread root & thread crown)
2. Threads per measurement unit

Given there are only really two measurements on a valve stem nut selection,
I thought the two lines in the Wikipedia weren't a mix but just two ways of
measuring the same thing?

Aren't these two different measurements measuring the same thing?
1. Metric: 7.7 mm OD, 6.9 mm thread root, 0.794 mm pitch
2. USA: 0.305 in OD, 0.271 in thread root, 32 TPI pitch

Right?
That means it's *not* a mix.
It's just like measuring a 5/32 and 4mm bolt, where both use the same
wrech.

My question is:
Isn't the tire valve NOT a mix of measurement standards?