Troul 

I use what the manufacture instructs to use. If none are available, I use my hot air to determine what is best practice. Metric is more likely used in general.

onsay99

Mostly MKS, but I am comfortable with both.

Gresp15C

I use whatever is convenient. Cycling related: Miles, Fahrenheit, metric dimensions on modern bikes, imperial on old bikes, some Whitworth threads too. Work related: Mostly metric, but some assemblies still have imperial fasteners. Many building materials have their own standards: Plywood comes in 4 x 8 foot sheets, but the thicknesses are not precisely in inches.

Living with two unit systems is an occasional minor inconvenience, but really doesn't matter any more. Modern design and production tools switch units effortlessly. Consumer products are mostly metric. The typical American household has a dwindling need for imperial tools.

79pmooney

Ship design pre computer - engineering scales in decimal feet. (I think there have been small wars waged to get those things.) With those scales you could go directly from the drawing to the math, no need to deal with inches and feet. Every design office, everyone knew who had that scale and it got borrowed a lot but you had to sign over your first born to get it.

vane171

We are lucky not having the old English currency and I think also their measuring system, that was something really devious. We are lucky that measuring calipers nowadays can display imperial values in fractional notation as well as decimal and convert btw the metric and imperial on the fly. With my carpenter friend, when we have done something together, I got used to call 1/16" parts the 'little guys' I would say for example, that it measures one and a half inch plus two little guys, which would be one and five eighth of an inch

Swampthing 

This is a sore spot with me.
I normally use metric, but sometimes have to use feet and tenths of feet, and at other times feet and inches.
I often report the same issues in metric and then in other odd units like switching from cubic meters per second, to gallons per second, to a number of acre feet delivered.
it’s enough to give one a headache.

Troul 

is there a difference when referencing midgets & dwarfs?
Does 4 midgets equate to 1 little guy? 7 dwarfs sum to 0.0625?

Flip Flop Rider

my weight is down to 5 stone

Troul 

Kidney?

jack pot 

Ronald Reagan did away with the US Metric Board as part of his American agenda ... this killed the metric conversion movement

mdarnton

"Both" isn't in the poll. My field uses both and I'm comfy with either.

cyccommute 

Just use “about” conversion. Rather than think of prices in terms of 167 pesetas to a dollar, think of them as 200 pesetas to a dollar. You’ll over estimate but in the end it’ll be close enough.

I’m very well versed in the metric system from my career but I don’t really use it much in my actual life. I don’t do the conversions but just estimate. For example, Fahrenheit to Celsius is mostly close enough if you just double Celsius to Fahrenheit, especially for higher temperatures. Not completely exact but close enough. For “normal” temperatures, remembering a few landmarks will help in conversions. The freezing point is water is 0°C which is easy. 20°C is 70°F which is pleasant and body temperature is 37°C so that’s hot.

I had to serve as a pro forma measurement interpreter when my wife and I did a Bike and Barge trip in Belgium. We were given a cue sheet and told to follow it for the route. The cue sheet would say something like “0.1: Turn right”. All us ‘Mericans were thinking a tenth of a mile (almost 600 feet or about 2 blocks). I had to constantly remind the other riders that Belgium uses metric distances so the “0.1” meant about 100 yards so just one city block.

One morning one of the Belgian guides was giving us a weather update and one of the ‘Mericans asked him what that temperature was in “real” units. He had no clue. I gave everyone a quick lesson in the temperatures above and everyone...’Mericans and Belgians...got it.

I do need a calculator to get exact conversions but for the most part we estimate most everything anyway.

Marcus_Ti

Actually...even 'imperial' units are actually metric.

The USA signed the International Yard and Pound treaty, along with Canada and Russia and the UK etc, way back in the late 1950s. This defined as a matter of international standards, and legally, that all the 'imperial' units were defined via metric measurements. All those 'imperial' measurements are actually defined in metric and then obfuscated, because--well--'murica'.

No matter what--the USA actually uses metric units--we just refuse to come out of the closet.

Cyclist0108

Atomic units.

That, and \alpha = 1/137

Not everything gets to be 1.

Gresp15C

I've forgotten all of them: e = c = hbar = g = i = 2 = pi = 0 = 1, or something like that.

My professor refused to use atomic units. He said it just led to formulas that couldn't be used for calculating anything, plus invited lots of dimensional errors.

In my view, metric failed in the US because of the way it was introduced. The message was, "metric is easy, it's just a bunch of math." Well, most people freeze up when they see math. I still remember a machinist who told me: "I hate the metric system because of all the math."

Cyclist0108

Work-wise, I always use metric units. Much more rational. Much easier math. Everything is base 10.

For things like observing the weather, purchasing gas, sizing clothing, etc, I use the crazy system that everyone does in the US. But I almost never have to do conversions (and if I do, I just use some google interface).

British pints are 20 oz rather than 16 oz. My wife ( who is British) thinks that this is a con that bartenders invented to cheat you out of 20% of your beer.

base2 

Blog post by an official site of the United States government.

On a related note: I used to run a NIST affiliated calibration lab in a former life. So I went to school for this.

More detail from the government.

Short story: All Imperial units are defined in metric. Not the other way around. The US is Metric in official capacities, Imperial by convention for the proletariat. Literally, it's because it just plain costs too much to change all the road signs & there's no compelling reason to do so.

Darth Lefty 

My favorite are bootleg metric units like calories (both sizes) and kgf. We have some really awful units for heat like BTU’s and kilowatt-hours and therms.

Considering the power output on a bike maybe we should be using dynes and ergs

In my job a few of the properties we use have an exponential relation (due to activation energy of a chemical reaction) and the units on that equation are... put back on after you get the result

Outrider1

No choice for both.

spelger

being BikeForums i automatically assumed the question would be understood to be directed to bikes.

being BikeForume i guess not.

Reflector Guy

I think it is because you asked, that we assumed it was a question about more than just bikes.

If your bike is metric, you're pretty much going to be using metric tools on it. I suppose you can search the toolbox for the closest SAE sockets and Allen bits which might fit, most of the time, but why? Proper metric tools which fit correctly are available everywhere and won't booger up the fasteners on your bike.

To put it another way, your car probably needs a 19mm socket to remove the lugnuts. A 3/4-inch socket will fit.... But it might damage the lugnuts. Why risk it?

guachi

For cycling I use metric because the numbers are larger.

Cyclist0108

The argument of an exponent or log has to be unit-less. So an equilibrium constant technically has no units. Students just love hearing about that.

Marcus_Ti

You're leaving out the most absurd unit of them all still in use in the USA air-conditioner 'tons'

veganbikes

I use Smoots, Tatums, Sagans and MegaFonzies. I also find Potrzebies and Banana Equivalent Doses to be acceptable as well. The silly Murican and EuroDisney measurements aren't really worth using, I mean they are so outdated.