Around The Corner - How Differential Steering Works (1937)

US Auto Industry17 HN recommenders · 2013–2024
22.3M views · explainer · evergreen · Uploaded 2009-09-16

A 1937 GM-produced film explaining how the automobile differential lets wheels turn at different speeds around a corner. It uses clear animations and cutaway demonstrations to build the idea from first principles.

Held up as a marvel of pedagogy and the best explanation of differentials, recommended again and again.

Watch on YouTube

20 comments from Hacker News

@aa02013 · in “Five Hundred and Seven Mechanical Movements”

That was a great video, thank you! Knowing basic gear mechanics helps a lot in understanding how cars function. This 1937 video about differentials is also enlightening: [VIDEO] Why is it that old tutorial videos are so thorough and informative?

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@aunty_helen2015 · in “How a car works (2012)”

This is great. As for the criticism that a lot of the content is old, most of the core concepts can be explained better with older tech as it's simpler. This allows you to focus on what is happening and leave the extra details about what technology a part or process has for a case by case basis. [VIDEO] is a great example of this. Saying that, an article on direct injection, common rail diesels, efficient turbo charging, variable valve timing, MAF VS MAP EFI would be worth considering.

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@japhyr2016 · in “4WD vs. AWD. What's the Difference?”

Here are the key takeaways for me: "Thanks to that differential between your axles, an AWD car will send your engine’s power down the path of least resistance—the wheel with the least grip. Where a two-wheel drive car can only choose between two wheels, an AWD system looks for that least resistance across all four wheels." "4WD works by locking the front and rear axles together, splitting torque 50:50 between them. This provides great traction, but a vehicle locked in 4WD cannot safely be operated on dry pavement because its front and rear axles are forced to rotate at the same speeds." I remember being scared when I bought my first 4wd vehicle, a '91 Toyota pickup. I knew I shouldn't have the wheels locked in 4wd on dry pavement, and I was worried about going from snowy roads to dry pavement. When I moved on to an Outback (AWD, not 4wd) I wondered why I didn't have to worry about transitioning between slippery roads and dry pavement. Now I understand. There's also a great video from 1937(!) that shows why we need differentials, and how they work. Here's a direct link to the video if you're going to skip the article: [VIDEO]

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@sheltron2018 · in “Walt Disney's MultiPlane Camera (1957) [video]”

Wow these are really great thanks for sharing. Heres a couple of others that I like. Differential Steering: [VIDEO] Turbo Encabulator: [LINK]

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@foobarian2018 · in “Honda will use GM’s self-driving technology, invests in Cruise”

This kind of mechanical device where there are more than two shafts are always cool. Classic video about differentials from 1937 (!): [VIDEO]

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@Raphmedia2018 · in “Space Transportation System”

Videos were very instructive back then too. At some point, we started to prioritize form over function. E.g. [VIDEO] [Around The Corner - How Differential Steering Works (1937)]

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@lqet2019 · in “Five Hundred and Seven Mechanical Movements (1908)”

A few months ago, this video [0] from the 30ies explaining a differential was posted on HN. It also is extremely interesting to watch. Minute 5 is very illuminating. [0] [VIDEO]

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@dTal2019 · in “Five Hundred and Seven Mechanical Movements (1908)”

Not just the 50s/60s - this video explaining differentials is from 1937 and is a marvel of pedagogy: [VIDEO]

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@ohaideredevs2019 · in “Ask HN: Your favourite tutorial for total beginners?”

How guns work: [LINK] How a car differential works: [VIDEO] Downright the best zero-to-programmer course in the world. Wish I knew about it when I was starting out: [LINK]

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@smogcutter2019 · in “South-Pointing Chariot”

Here’s a terrific explanation of how differential gears work, from a film produced by GM in the 30s: [VIDEO]

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@Arnavion2020 · in “How to Use a Differential Analyzer”

[VIDEO] is the non-clickbait-title version, hosted by the channel with other popular recovered films in the same genre.

@throw12346512342020 · in “Why are Soviet math textbooks so hardcore in comparison to US textbooks? (2017)”

I find this to be true. It seems like there was more focus on the very, very basics. Now there is a ton of filler and the content gets lost. E.g.: [VIDEO]

@sajforbes2020 · in “Calculus Made Easy (1914) [pdf]”

A similar thing - the best explanation I've seen about how cars' differential steering works comes from 1937. [VIDEO]

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@paulkrush2021 · in “3D Printed South Pointing Chariot”

I am surprise I have not seen this, with how many times I have run across the Around The Corner - How Differential Steering Works (1937): [VIDEO]

@AussieWog932021 · in “Patterns in Confusing Explanations”

First thing I thought of when you said that: [VIDEO] Done properly, it's an amazingly powerful way of explaining things.

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@ironmagma2021 · in “Ask HN: What practical skills do you recommend?”

I would maybe start with the individual components. How a differential works: [VIDEO] There are a number of videos of transparent engines: [LINK] But if that doesn’t work, searching YouTube for “how an engine works” should give lots of content. Once you’ve figured out how the engine turns the flywheel, you can investigate how the flywheel applies different speeds to the wheels via a transmission. Manual transmissions are simpler, so I would start there: [LINK] then figure out how the clutch fits in. After that, you can move on to torque converters (coolest component imo, basically a fluid coupling) and automatic transmissions, which can be a mind-bender. Feel free to reach out to me at pc.peterso at Mail of g dot common TLD, happy to share what I learned and save you some time. Lastly, there is a wealth of tidbits on Engineering Explained and howacarworks.com, although the latter goes into far more detail than you probably need.

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@bramhaag2023 · in “Hydraulic Steering – Principles of Operation (1956) [video]”

Similar videos about cars: Chevrolet Suspension (1938): [LINK] How Differential Steering Works (1937): [VIDEO] How A Transmission Works (1936): [LINK] And as a bonus, an explanation about transistors from 1953: [LINK]

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@deaddodo2023 · in “1962 Military Innstructional Video on Magnetic Cores”

All of the old US gov't/mil funded education films are pretty good. * [VIDEO] * [LINK] * [LINK] * [LINK] * [LINK] Etc.

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@nixass2024 · in “The Basics of How Engines Work (2021) [video]”

One of the best "how this mechanical thing works" for me is about differential/steering by Chevrolet (1937.). It's almost 100 years old by now but still one of the best "how" videos ever. [VIDEO]

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@mdorazio2024 · in “Basic Mechanisms In Fire Control Computers (1953) [video]”

Not just military training videos, older ones in general are often superior to what gets made today. My favorite is probably this one on vehicle differentials: [VIDEO]

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