After finally getting a couple of the new spur 20T clutch gears, I was struck with an idea for a new gearbox setup I could make, making use of their ability to drive chains. Because of this, and the new 12T and 20T spur gears, there's actually a lot of options for gearing, which can be done in a straight line, much like a real car's gearbox.

I built two versions of this gearbox, which were a bigger 5+R gearbox, with these gears:

R: 20:28, direct drive rather than chain

1: 20:24

2: 20:20

3: 20:16

4: 20:14

5: 20:12

By nature, this gearbox is very close range, and the fact that I used the old and chain-capable 14T gear to get a fifth speed makes some speed changes extremely small. Additionally, doing six positions with the wave selectors is tricky. I did it by offsetting them by connecting them all to another axle beside it with 12:20 gearing, which, because 12 is divisible by 3, allowed me to space three of them apart evenly, making only one ring engaged at once.

Because of these reasons, and its size, I figured that most people wouldn't be interested in using it, so I also built a much more basic 4-speed version, with 20:24, 20:20, 20:16, and 20:12 gears and a straightforward wave selector setup. Unfortunately, I took it apart last night after it had been sitting on the shelf for a while, and only just now realized that I didn't take any videos of it... It should be pretty easy to figure out how it would have looked based on this 5+R one, though.

I'm not sure how the chain would hold up to heavy use, but it is a refreshingly straightforward way to get lots of speeds in a Lego transmission!

By the way, I only had two of these gears from Lego, so I had to 3D print the other four. It still worked fine!

Edited April 23, 20231 yr by 2GodBDGlory

Nice gearbox!

Chainlinks can handle more torque when put on inside out. Can be observed here:

 

Good to know! I seem to remember The Unofficial Lego Technic Builder's Guide suggesting the opposite, but those tests look convincing, and make sense to me, so I'll change my practice.

Wow, something new! Will investigate how it works!

This is very interesting. I would like to build it so I can try it myself. Are there any instructions for it?

38 minutes ago, 1963maniac said:

This is very interesting. I would like to build it so I can try it myself. Are there any instructions for it?

No, sorry. If you have specific questions about something I can answer I'd be happy to help, but I think the working principle is simple enough to copy