22.3M views · Sep 16, 2009 · 9:31 · 17 HN recommenders · 20 mentions · discussed 2013–2024
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.
Why Hacker News points people here: Held up as a marvel of pedagogy and the best explanation of differentials, recommended again and again.
“this video explaining differentials is from 1937 and is a marvel of pedagogy”HN comment, 2019
“This 1937 video about differentials is also enlightening”
Thorough 1937 explanation of how differentials work.
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: this video Why is it that old tutorial videos are so thorough and informative?
“this video explaining differentials is from 1937 and is a marvel of pedagogy”
1937 differential explainer praised as a marvel of pedagogy.
Not just the 50s/60s - this video explaining differentials is from 1937 and is a marvel of pedagogy: this video
“Here’s a terrific explanation of how differential gears work, from a film produced by GM in the 30s”
Terrific GM-produced explanation of how differential gears work.
Here’s a terrific explanation of how differential gears work, from a film produced by GM in the 30s: this video
“the best explanation I've seen about how cars' differential steering works comes from 1937.”
Best explanation of differential steering the commenter has seen.
A similar thing - the best explanation I've seen about how cars' differential steering works comes from 1937. this video
“Done properly, it's an amazingly powerful way of explaining things.”
Example of an amazingly powerful way of explaining things.
First thing I thought of when you said that: this video Done properly, it's an amazingly powerful way of explaining things.
“It's almost 100 years old by now but still one of the best "how" videos ever.”
Still one of the best how-it-works videos ever.
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. this video
“My favorite is probably this one on vehicle differentials”
Favorite old video on vehicle differentials.
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: this video
“is a great example of this.”
Example of explaining core concepts with simpler older technology.
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. this 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.
“There's also a great video from 1937(!) that shows why we need differentials, and how they work.”
Shows why differentials are needed and how they work.
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: this video
“Heres a couple of others that I like. Differential Steering”
Liked explainer on differential steering.
Wow these are really great thanks for sharing. Heres a couple of others that I like. Differential Steering: this video Turbo Encabulator: link
“Classic video about differentials from 1937 (!)”
Classic 1937 video on differentials and multi-shaft mechanisms.
This kind of mechanical device where there are more than two shafts are always cool. Classic video about differentials from 1937 (!): this video
“Videos were very instructive back then too.”
Example of instructive old videos that prioritized function over form.
Videos were very instructive back then too. At some point, we started to prioritize form over function. E.g. this video [Around The Corner - How Differential Steering Works (1937)]
“It also is extremely interesting to watch. Minute 5 is very illuminating.”
Extremely interesting 1930s differential explainer with a key insight at minute 5.
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] this video
“How a car differential works”
Listed as a favorite tutorial for total beginners.
How guns work: link How a car differential works: this video Downright the best zero-to-programmer course in the world. Wish I knew about it when I was starting out: link
“I would maybe start with the individual components. How a differential works”
Starting point for learning how car components work.
I would maybe start with the individual components. How a differential works: this 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.
“Similar videos about cars”
Listed among similar old educational car videos.
Similar videos about cars: Chevrolet Suspension (1938): link How Differential Steering Works (1937): this video How A Transmission Works (1936): link And as a bonus, an explanation about transistors from 1953: link
“All of the old US gov't/mil funded education films are pretty good.”
One of the pretty good old government educational films.
All of the old US gov't/mil funded education films are pretty good. * this video * link * link * link * link Etc.
“is the non-clickbait-title version, hosted by the channel with other popular recovered films in the same genre.”
Pointed to as the non-clickbait-title version from a channel of recovered films.
this video is the non-clickbait-title version, hosted by the channel with other popular recovered films in the same genre.
Offered as an example of focus on basics without filler.
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.: this video
Commonly encountered 1937 differential video.
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): this video
