Early Derailleur (I think)

Graham

Cruising
Feb 4, 2014
18
13
23
58
Minato-ku, Tokyo, Japan
Does anyone have any knowledge of how this might work? There were two bikes displayed on the wall of a restaurant I was in last night; one was a normal fixie and the other had this odd gearing. I`m told it is an early form of derailleur; and that you pedal backwards to change gear; but do we know more? Restaurant was Les Valseuses in Prenzlauer Berg, Berlin so a bit off IMG_0545.JPG the TCC radar screen perhaps.
 
  • Like
Reactions: bloaker

Half-Fast Mike

Lanterne Rouge-et-vert
May 22, 2007
4,153
2,710
143
Kawasaki
halffastcycling.com
Pedalling normally will turn the smaller sprocket in the forward direction. Reversing the pedalling action will turn the larger sprocket in the forward direction. Presumably there are two independent and opposing freewheels allowing the non-engaged sprocket to coast. Ingenious.

Edit: once you see what's happening, it's easier to find
http://en.wikipedia.org/wiki/Retro-direct
 
Last edited:
  • Like
Reactions: bird

bloaker

Sincerely A Dick
Nov 14, 2011
2,624
3,495
433
Miura, Japan
Wow! Thanks for noticing, taking a picture and asking.
I have never seen anything like that before. Very interesting!
 

GSAstuto

Maximum Pace
Oct 11, 2009
947
243
103
tokyo
www.roadfixie.com
Mike is correct - this a retro-direct gearing. You pedal forward for the higher (faster gear) and backward for the lower (slower) gear for climbing. One way to avoid 'flip flop' on the steep hills... the later versions usually had a front chainring derailler so you could actually get a 4 speed with very wide range!
 

Cactaur

Maximum Pace
Feb 3, 2014
202
137
63
Very cool. It's going to mess with peoples minds nowadays to see someone pedaling backward up a hill.
 

bloaker

Sincerely A Dick
Nov 14, 2011
2,624
3,495
433
Miura, Japan
So,... can your coast? It seems it would be possible and if you pedal forward or back, as long as you pedaled slower than the bike, it would be fine. But having never seen this before, I am just trying to think it out.
I would be awful if there were any accidental engagements.
 

TCC

Tokyo Cycling Club
Jun 30, 2013
2,360
1,294
133
Both the freewheels engage in the same direction, so freewheeling behaves normally.

I would like to see how the freewheels attach to the hub shell. I suspect two co-axial threaded tubes with the smaller extending further than the larger
 

theBlob

Bokeh master
Sep 28, 2011
2,978
1,648
129
...
Ha ha ha love it... This thread has it all going on!
 

TCC

Tokyo Cycling Club
Jun 30, 2013
2,360
1,294
133
Warning. That is not the real TheBlob.

I think.
 

TCC

Tokyo Cycling Club
Jun 30, 2013
2,360
1,294
133
My mistake. Your IP checks out.

Sorry about that.