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The Dirty Gearhead Phrase That Isn’t: Balls to the Wall

The Dirty Gearhead Phrase That Isn’t: Balls to the Wall

It is a phrase that lots of gearheads use frequently and probably few know the origin of. When you’re yapping with buddies and tell them that you’re going to run your car, “balls out” or “balls to the wall” you mean that the car will get run full on, to the floor, with everything she’s got. It sounds dirty and inappropriate as hell, but here’s the thing. It isn’t. You’re actually referencing a steam engine when you say that.

James Watt, one of the pioneers of steam engine development in the early 1800s invented lots of stuff. One item was the “fly ball regulator” which worked to regulate steam pressure and speed in a steam engine. As pictured below, the regulator used two balls mounted on arms. These were usually made of iron or brass and depending on the size of the engine they were used on, varied in weight and other details. They all worked the same though.

The regulator was hooked to the flywheel and as the flywheel spun, so did the regulator. As it spun faster the centrifugal force would cause the balls to raise higher and higher until the engine reached full speed at which point the balls would be “out” and facing toward the wall. At this point, the regulator would vent steam to keep the engine from running away or experiencing an explosion due to too much pressure.

As gearheads you know we make up saying and expressions to describe stuff all the time, so when these regulators became virtually standard and chief engineers asked mechanics at what speed an engine was running, they’d reply, “balls out” or “balls to the wall” to indicate it was humming along at full steam.

You’ll still never be able to utter the phrase at church, but the next time one of your bench racing pals says it, ask if he knows what it means and where it came from. Chances are he doesn’t!

Watt Flyball Regulator

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10 thoughts on “The Dirty Gearhead Phrase That Isn’t: Balls to the Wall

  1. Beagle

    Hell, even Monica knows that! lol. I love that expression… kinda like WFO, which isn’t clean but hey, whatever.

  2. Joe Henderson

    Yes, this was also an old nautical term (for the reasons above) because of where the engines were used.

  3. sbg

    From the Urban dictionary:
    Balls to the wall
    To push to the limit, go all out, full speed.
    A very colorful phrase, one needs to be careful when using “balls to the wall”. Although its real origin is very benign, mos people assume it is a reference to testicles.
    In fact it is from fighter planes. The “balls” are knobs atop the plane’s throttle control. Pushing the throttle all the way forward, to the wall of the cockpit, is to apply full throttle.

    1. Lee

      That is the correct origin – pushing the throttle control lever balls to the firewall.

      The steam engine definition came from Jay Leno and is not the correct origin

    2. Dude

      Yup, “Balls to the Wall” and “Balls out” (never heard that one in use) have completely different entomologies.

  4. Manifestospeed

    But it’s the double entendre that keeps a phrase from the steam era in the current vernacular.

  5. Ron Ward

    I always found it interesting that in bracket racing, the guy with the smaller package wins…

  6. 67pete300

    Brian, this reminds me that youshould visit the Charles River Museum of Industry in Waltham if you haven’t already. They have tons of cool stuff. Many with “balls” like these.

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