Re: Only 14 gear ratios? Primitive!

On 12/4/2024 9:39 AM, Zen Cycle wrote:

On 12/4/2024 9:54 AM, AMuzi wrote:

On 12/3/2024 11:05 PM, Frank Krygowski wrote:

Bike transmissions: Derailleurs are easy to understand. Internal gear hubs are more complicated. (When I was teaching, I had our machinist do a cutaway of a Sturmey- Archer AW hub and mount it on a display stand near an explanatory poster, so interested students could see what made it work.)
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Rohloff 14 speed gear hubs are an order of magnitude more complicated than AWs. But this new gizmo makes a Rohloff look like child's play. It's a true continuously variable transmission, with an infinite number of gear ratios, that is completely gear-based. No slipping surfaces, and supposedly minimal friction losses.
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Here's the link to the half hour explanation video:
https://www.youtube.com/watch?v=mWJHI7UHuys
You may want to start at about 14:30 before returning to the beginning to digest the super-complicated explanation of it's operation.
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No info in the video about prototype weight, efficiency, etc.
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Brilliant and clever! Thank you.
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I can only see complexity, cost to fabricate and weight as downsides, none of which would be deal breakers for some applications. Motor power for example.

 It actually seems to me to be significantly less complicated than a standard automatic transmission
 

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Sort of the inverse of fixed, which are dirt cheap, light and reliable at the cost of zero gear variance.
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 Nothing a good pair of legs can't handle :)
 

I have to admit I don't know much about modern electronic control slushboxes (except to avoid them) but the geared CVT is much more complex than what I drive* and infinitely more complex than what I most often ride (fixed)
* https://corvair.com/user-cgi/catalog.cgi?show_page=130
--
Andrew Muzi
am@yellowjersey.org
Open every day since 1 April, 1971