A derailleur that does not have a parallelogram

I made a DIY derailleur that does not have a parallelogram. This isn’t practical enough, but I’m happy with the unique mechanism of the derailleur.

It looks like it’s moving.

When I first made this, it was the first mechanism in the world! I thought.
However, when I looked it up, I found that the mechanism of FSA K-FORCE WE was the same.

Another derailleur that does not use a parallelogram is the slide shaft type, but the world’s first electric derailleur, the MAVIC ZAP, is also a slide shaft type.

Do you know what other parallelogram derailleurs do not use?


Well everything before the Nivex in about 1937 and lots after it.

Check out Disraeli Gears for history, including such wonders as the White Industries LMDS:


I learned a lot from Disraeli Gears.
By the way, Nivex is the world’s first parallelogram derailleur!
White Industries LMDS is a slide shaft type derailleur.

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Very impressive machine work–and, it actually works–pretty amazing!!

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You could also look at a Campy Croce d’Aune rear derailleur released in 1988. It is a non-slant parallelogram, one of the oddest designs ever made.

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I used to have one of those, although it isn’t slanted it does have a parallelogram and fairly ordinary shifting due to slop in the uper ball and socket. Better than the Huret Jubilee it replaced but that’s not saying much.

It’s a strange and interesting design. I am attracted to that gimmick.

In pursuit of performance, today all of them are the same slanted parallelogram derailleur.
I think the FSA K-Force WE is the only derailleur that doesn’t have a parallelogram in the current product.

From an engineering perspective, would there be some advantage to not using a parallelogram? It seems like this would just be an inherently heavier and less rigid design to me but I’m admittedly no expert in that regard.

In short, no. That’s why nearly everyone uses parallelograms.

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That’s why I make a derailleur that doesn’t have a parallelogram.
If I enjoy making DIY, I will make something that everyone does not make.:wink:


Wow, you’re amazing - I love your cool projects. :slight_smile:

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Thank you.:heart::heart:

I love the ingenuity on display here and in your other projects.

Here’s a thought: the parallelogram derailleur became dominant because it is simple, robust and a reasonable approximation of the ideal travel path for the upper jockey wheel, especially if it is slanted. A reasonable approximation.

One point of difference is that the curvature of the parallelogram path has the opposite sense to that of the ideal path: the parallelogram follows a convex path while the cogs are concave (unless you are running a straight block (aka corncob) but I haven’t seen one of those since the 80’s).

I wonder if you could adapt your cog mechanism so that it caused the jockey wheel to follow a concave path as it travelled over the cogs. It would be interesting to see if it actually made a difference to shifting performance.

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I noticed a mistake, so I will cancel the post.

Your thoughts are great!
Thanks to that, I could understand the advantages of the renewed Nivex.

Campagnolo already patented it for their Ekar rear derailleur:

It’s a mechanism that reminds me of CROCE D’AUNE.
For mechanical derailleurs, don’t you think Nivex simply serves that goal?

Thanks, I hadn’t seen that.

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