It is incredible how this vintage speedometer works!

[spencerh]

Honestly had no idea that's how it worked

[ndfloorsongs]

Another reason it's hard to open is they don't want you messing around with the odometer. But on a lot of the old cars and motorcycles, you could actually run the thing backwards with a... Oh my gosh, an electric drill!

[DuckWasHere]

Thank god for trump telling everyone that magnets don’t work in water, I tried magnet fishing again and suddenly the magnet stopped working the instant that it hit the water

[patricksandeberg]

Yeah magnets not working under water Trump 😆👌🏾.
That’s why my magnet fishing is so difficult 😅

[Zigonce]

I figured it had to be some kind of clutch/spring combo. Didn't think they would've used magnetic couplers🤔

[jamesrindley]

It works because the spinning magnet induces eddy currents in the stationary cup. The magnitude of those eddy currents depends upon the relative speed of the magnet and the cup. The eddy currents create a force which tends to oppose the motion that created them (Lenz's law), thus the force will tend to rotate the cup against the spring.

[cheetodanger]

Magnets don't work underwater, I didn't know that Mr President thanks for teaching everybody that piece of factually correct information 👀

[Tasselhoff]

So you're a couple days late on my restoration project. I just opened and cleaned up my stuck speedo. Don't tell me your next bit is about two stroke pipe's expansion chambers 'cause I'm welding up mine tomorrow.

[windshieldraindrops]

Magnet created " Eddie current" in the opposite disk

[frosty]

I had an old Mazda B 2000 pich up. Grease from the cable would work up into the speedo and stick the magnet and cup together.

[Sir_Cactus]

I alwayswondered how they worked. My best guess was that it used a spinning magnet to induce a current in a coil. The Voltage would then be meassured using one of the super old school volt meters which use magnetic repulsion to meassure the voltage. However, on such a system the inertia of the needle would be quite problematic, especially when leaning into corners or driving on a bumpy road.

[LAWLESSKING]

Thank you for the reminding the world the lack of knowledge.

[ramishrambarran]

Magnetic flux !
What destroys those type of speedometers and tachometers was vibration.
Vibration from the engine and the constant shaking from using the bike.
I sill prefer those over digital, LED, and those printed circuitboards they use today.
Those speedometers and tachometers helped define the motorcycle for what it was !
Trinidad & Tobago.
West Indies.

[simplyelectronic]

Works with the induction of eddy currents on the round bit around the magnet. This effectively turns the little shell bit into another magnet thag is stronger with speed. Thus, the needle can fluidly drop and rise because of the build and decay of the curents.

[matthewbrown]

Not only did you answer a question that's been floating around in the back of my head ever since tinkering with my first classic bike, the clip at the end caught me off guard and made me laugh out loud 😂

[polymerkiki]

That's really interesting! I never thought there'd be magnet. I thought it was just a very clever engineering of springs and gears

[CommonBovine]

So it's basically a magnetic slip clutch. That's pretty neat!

[JStoppie]

😂

One thing I remember of the mechanical speed- and odometer of the 1982 Guzzi V50 III I used to have is that the cable only lasted 200km.

Which also explained why it only had 48000km on the counter and why I ran out of gas a few times. (The reserve valve also leaked and I’m not that good in estimating how much I have driven)

Interesting tech nevertheless 🤓

[meritholdingllc]

The Trump quote is funny, but if love to know the context of what he said.

[timothym]

The odometer isn’t fed by the magnetic coupler. Only the speedometer needle.