crank_addict

I'd like to give this one a shift

tiger1964 

Looks like a dirt-catcher design and it sounds like he almost put it into the spokes... but neat fabrication skills.

fietsbob

50s bikes had the RD mounted further ahead , on the chainstays , in about that location..

crank_addict

True that but even earlier. I have this mid- 1930's hanging on a late 50's era bike. Acquired it NOS including cable, lever and instructions (French print). The instructions show where to drill an index hole under the chainstay, the idea for the mount bracket to remain in position.

[IMG]IMG_7139 by carrera247, on Flickr[/IMG]

Spaghetti Legs 

Very cool. I also like the chainstay protector although I can’t tell how it’s secured.

nlerner

If I wanted something to shift that poorly, I’d just used Campy NR.

Spaghetti Legs 

Yeah but you make it yourself! It would be just like all the other half ass kludges around my house.

Chombi1 

Plunger type mechanisms on derailleurs are not new with many of them that came and went through the ages, but not sure If a rack and pinion type like this was tried out yet. This one can be further developed with a top cover, bellows and seals to keep the grunge and moisture out of the internal mechanism.
Makes the rear dropout and RD a bit more susceptible to crash damage, as it is fully rigid, without that bit of "give" that a typical springed/jointed RD has.

steelbikeguy

Credit to the creator for tinkering and coming up with something that works (mostly)!

It would be interesting to learn what the creator knew about the history of the derailleur, and specifically, if he/she knew about plunger derailleurs. I always liked how the plunger derailleurs used a linear movement of the cable to produce a linear movement of the pulleys. The creator of this derailleur chose instead to convert the linear cable movement to a rotary motion by wrapping it around a drum, and then converted that back to a linear motion with the rack and pinion. Seems like a lot of added complexity with no particular added value.
Of course, I've never shifted a plunger derailleur, so maybe I'm missing something??

Steve in Peoria
(I make my own bike headlights, so I applaud anyone who goes out and makes something that is already commercially available. Making stuff is fun!)

steelbikeguy

cool stuff!
Does it just use the cable to make the change in direction? Doesn't seem like there's enough room to use the tiny chain like so many other designs.


Steve in Peoria

Chombi1 

What might have been lost is the angular tracking of the jockey wheels to stay near to the cogs
as what was pioneered by the Japanese with the angled parallelogram designs that was eventually copied by everyone. I guess that feature
can be somehow added into the design.

JosephCP

Thats quite a design...looks like an old Huret.

Wileyone 

Mine work fine. Let us know the problems you are having and maybe we can help you sort them out.

ThermionicScott 

That's neat! It reminds me of some of the things I see in "The Dancing Chain" where all kinds of derailleur designs were tried when the technology was brand-new and any idea you could think of was on the table.

If that rack-and-pinion one were scootched backward a little in relation to the mounting bolt, and perhaps angled a little to move with the freewheel, I could see it shifting a lot better. But with the added complication, I see more opportunities for it to gum up and not work well if dirt got into it.