Linear Derailleur Mechanism

sundaydoug

sundaydoug

Well-Known Member
For those that haven't seen this, Yeti is attempting to improve on the conventional derailleur by replacing the popular parallelogram design with a linkage system that promises true linear mech movement with respect to the wheel.

It's a tech-heavy article, but interesting. Especially the pulley axes graphs. Very promising, especially for those of us in the "form follows function" minority crowd.

https://wheelbased.com/2021/01/25/l...6I6AveTbFPYISkJ9mrq4p40WDuwPiAqSFbuUpsUho2JKg
 
good stuff -

couple of thoughts -
- i'm still going to smash it on a rock and knock it out of whack. can i grab it and "fix" it.
- seems a couple stepper motors and a little programming could do the same thing - so no pulleys or parallelogram.
(it bothers me that the big Ss just replaced the pulley with a motor without thinking what they really could do.)
 
Dingo said:
like make a lite weight-strong-durable-affordable internal 12 speed hub ?
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as always - replace your constraints as needed. I was too lazy to mash one up myself.

how nice would an internally geared, belt drive be!!!

1612305596470.png
 
This is a lotta hoopla ain't it? Ever think Derailleurs are non-linear to follow the path of the chainline? Or to keep the distance from the cog constant? You think a tiny little company like Yeti is going to do something Shimano or Sram hasn't already figured out? For real.
 
Feel like they are trying to fix something that isn’t broken (well, Patrick broke it l, but the rest of us).

and Patrick, shimano shadow sits 2” less than sram.
 
jimvreeland said:
Ever think Derailleurs are non-linear to follow the path of the chainline?
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I considered that after reading this article. If that were the case though, I'd expect to see equal value/opposite sign (one positive one negative) non-zero pulley axes yaw values (relative to the wheel axis) at each end of the cassette, with a zero somewhere close to the middle. To compensate for chain angle of the low gear and equal, but opposite chain angle of the high gear, respectively.

That's not what Yeti's data shows us for either of the SRAM or Shimano groups. Also, the pitch angle plots are entirely different for SRAM and Shimano.
 
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jimvreeland said:
You think a tiny little company like Yeti is going to do something Shimano or Sram hasn't already figured out? For real.
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Yes, I think it's entirely possible that Yeti employs a person (or team) with the brainpower to improve on an existing design, even if it's not related to bicycle suspension.
 
53 years ago, I had one of these, on a well used 2nd hand bike. It was cheap, relatively lite, reliable, er until I smashed the chain thingy.
In all this time they cannot come up with something better than what the french designed in 1905?
sturmey.jpg
 
Dingo said:
53 years ago, I had one of these, on a well used 2nd hand bike. It was cheap, relatively lite, reliable, er until I smashed the chain thingy.
In all this time they cannot come up with something better than what the french designed in 1905?View attachment 150755
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They try. Problem is how outrageously heavy even the highest end Rohloff is. Like a rear wheel weighs more than my whole bike it feels like. It's insane. Also, internal hubs are made for Commuters so they pop out of gear at like 250 watts. All of them do.
 
jimvreeland said:
They try. Problem is how outrageously heavy even the highest end Rohloff is. Like a rear wheel weighs more than my whole bike it feels like. It's insane. Also, internal hubs are made for Commuters so they pop out of gear at like 250 watts. All of them do.
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Right, so why have these not been improved. Paging Elon to the CAD room...
 
Dingo said:
Right, so why have these not been improved. Paging Elon to the CAD room...
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Probably because of the billions of little tiny gears. The old ones were a lot simpler. Also, a Rohloff is like the same price as AXS. If they made it better it'd be like $3,000.
 
Dingo said:
53 years ago, I had one of these, on a well used 2nd hand bike. It was cheap, relatively lite, reliable, er until I smashed the chain thingy.
In all this time they cannot come up with something better than what the french designed in 1905?View attachment 150755
Click to expand...

*cough*English*cough*

But yes. Big money in improving a gearbox that doesn't weigh a ton/has reasonably good range. Shimano has patients pending for that, too.
 
Patrick said:
again with the cables. Make a stepper motor part of the gear selection system with a strain gauge
and feedback to let-up a bit when shifting.

oh how nice and quiet this would be!
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Maybe Shimano should get back into the motorcycle game, too. They used to make moped brakes.
 
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