Tech Tidbit: How a Differential Works

Interesting | July 3rd, 2011 by 6
24-hr-nurburgring-BMW-59

Every car (of recent vintage) has a differential and most people take them for granted without any idea of what they do, why they’re needed, …

Every car (of recent vintage) has a differential and most people take them for granted without any idea of what they do, why they’re needed, or how they work.

Going around a corner in a four wheeled vehicle requires the inside tire to travel at a slower speed than the outer tire. If the two drive sides were ‘locked’ into rotating at the same speed, the inside tire would be forced to slip/scrub. So differentials are employed to provide the ability of the driven wheels to rotate at different speeds when cornering.

The following video (unearthed from some GM vault – black and white and hokey in the extreme at the beginning and end) does as good a job of explaining basic differential operation as I’ve seen. Be forewarned though, the first 1:50 seconds of the video are painful to watch – unless you’re into campy motorcycle stunts.

Tech Tidbit: How a Differential Works

In the grand scheme of things, differential gears (that we would recognize as useful for automotive applications) have been around since the 1820s. And limited slip differentials are just what the name
implies, differentials that limit slip. More on those later . . .

Thanks, and a hit tip, to Roy DeGregory for dredging this up from the bowels of the intertubes and sharing it with me!

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  • Asdsdf

    thx for this but i have a question: what about FWD cars? do they have a differential or sth else?

    • http://www.facebook.com/profile.php?id=100000477069969 Hugo Becker

      Yes, FWD cars have differentials. Most have the differential in the same case as the transmission.

      The key is, whatever wheels are driven, you’ll need a differential. So for AWD/4WD you’ll have a differential on both axles.

  • http://twitter.com/mnmn90 Korin Bates

    who let the dogs out? http://derwan.my3gb.com/360.htm

  • Guest

    Oh come on! The first 1:50 is the most fun! Look! I can stand and ride! Now I can hold my male buddy’s crotch against my head and ride!

    Right, now some stuff about differentials…

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