Advertise on Bikeforums.net



User Tag List

Results 1 to 14 of 14
  1. #1
    Part-time epistemologist invisiblehand's Avatar
    Join Date
    Jun 2005
    Location
    Washington, DC
    My Bikes
    Jamis Nova, Bike Friday NWT, STRIDA, Austro Daimler Vent Noir, Haluzak Horizon, Salsa La Raza, Hollands Tourer, Bike Friday tikit
    Posts
    5,224
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    chain tensioner at end of derailer?

    Hi ... I saw the following in the MIT V8 thread

    MIT-V8 800x600.jpg

    To me it looks like a chain tensioner attached to the end of the tension pulley. Since it's a Brompton clone, I assume it's needed when the bike folds given that the distance between the derailer and crank decreases.

    However I imagine that it could have other uses as well. The derailer in the picture might be a short cage rear derailer to minimize the chance of striking something on the ground. The additional chain tensioner could pick up additional slack from the length of chain needed for the triple.

    Does anyone know what that thing is and where one might get one?

  2. #2
    coprolite fietsbob's Avatar
    Join Date
    Jun 2010
    Location
    NW,Oregon Coast
    My Bikes
    7
    Posts
    3,368
    Mentioned
    50 Post(s)
    Tagged
    0 Thread(s)
    Fabricate , DIY.

    apparently nobody even imports the whole 'mit' bike to the US let alone the parts ..

    suntour decades ago made a 3 pulley cage

    over on the I BoB list someone demo'd how they modified an existing RD .. they made the parts themselves.


    a drill and a jewelers hand saw hand files and time can make things..


    though the CAD CAM and 3D printer is now the other end of the Tech spectrum now.

  3. #3
    Senior Member smallwheeler's Avatar
    Join Date
    Aug 2012
    Location
    NYC
    Posts
    1,756
    Mentioned
    7 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by fietsbob View Post

    suntour decades ago made a 3 pulley cage
    awesome:



    extraordinarily idiotic:


  4. #4
    coprolite fietsbob's Avatar
    Join Date
    Jun 2010
    Location
    NW,Oregon Coast
    My Bikes
    7
    Posts
    3,368
    Mentioned
    50 Post(s)
    Tagged
    0 Thread(s)
    Like I said, Its so low to the ground it could be a kickstand ..

    It's why an IGH makes so much more sense than a long cage RD on a small wheel folding bike ..

  5. #5
    Senior Member bhkyte's Avatar
    Join Date
    Sep 2008
    Location
    York UK
    My Bikes
    2X dualdrive Mezzo folder,plus others
    Posts
    2,275
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by fietsbob View Post
    Like I said, Its so low to the ground it could be a kickstand ..

    It's why an IGH makes so much more sense than a long cage RD on a small wheel folding bike ..
    Agreed. I have just realised this is one advantage of dual drive instead of a triple. I have no problems with my short cage on my dual drive 349 bikes.

    Can't the one from a birdie be used. That's unobtainable also?
    Dual drive Mezzo (GOLD), Dual Drive Mezzo with bullbars (black), White Brompton thingy with Dahon Androes stem and bull bars. Birdie (old sytle) 7 speed. Downtube NS8. Birdie red.

  6. #6
    coprolite fietsbob's Avatar
    Join Date
    Jun 2010
    Location
    NW,Oregon Coast
    My Bikes
    7
    Posts
    3,368
    Mentioned
    50 Post(s)
    Tagged
    0 Thread(s)
    Brompton's 3 speed if the chain length is right, (Fairly short) tucks right up high .. ..

    then for me, the low gear is the 2nd range in the Mountain drive crank 54/21.6t [ a 50/20 is even numbers]


    though running a 110 BCD speed-drive the 34t acts like a 54t when kicked in overdrive

    (but chain never moves, 1 cog 1 chainring.) .

  7. #7
    lowlife bottom feeder BassNotBass's Avatar
    Join Date
    Apr 2008
    Location
    Lou-evil, Canned-Turkey USA
    Posts
    1,855
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    What's wrong with dual short cage derailleurs? It's such a simple arrangement and I bet it would work great.
    Last edited by BassNotBass; 04-10-14 at 05:31 PM.
    I plan on living forever... so far so good.

  8. #8
    Part-time epistemologist invisiblehand's Avatar
    Join Date
    Jun 2005
    Location
    Washington, DC
    My Bikes
    Jamis Nova, Bike Friday NWT, STRIDA, Austro Daimler Vent Noir, Haluzak Horizon, Salsa La Raza, Hollands Tourer, Bike Friday tikit
    Posts
    5,224
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by fietsbob View Post
    Like I said, Its so low to the ground it could be a kickstand ..
    I think that the original picture in the thread had a Shimano SS or GS road derailer. I can't tell for sure.

    There are reasons to pick something other than an IGH.

  9. #9
    Part-time epistemologist invisiblehand's Avatar
    Join Date
    Jun 2005
    Location
    Washington, DC
    My Bikes
    Jamis Nova, Bike Friday NWT, STRIDA, Austro Daimler Vent Noir, Haluzak Horizon, Salsa La Raza, Hollands Tourer, Bike Friday tikit
    Posts
    5,224
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by BassNotBass View Post
    What's wrong with dual short cage derailleurs? It's such a simple arrangement and I bet it would work great.
    That's interesting.

  10. #10
    Senior Member smallwheeler's Avatar
    Join Date
    Aug 2012
    Location
    NYC
    Posts
    1,756
    Mentioned
    7 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by BassNotBass View Post
    What's wrong with dual short cage derailleurs? It's such a simple arrangement and I bet it would work great.
    i think its really down to the needs of the individual cyclist.


  11. #11
    lowlife bottom feeder BassNotBass's Avatar
    Join Date
    Apr 2008
    Location
    Lou-evil, Canned-Turkey USA
    Posts
    1,855
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by smallwheeler View Post
    i think its really down to the needs of the individual cyclist.

    Now that's what a pro can do with PS! LOL... simply awesome!!
    I plan on living forever... so far so good.

  12. #12
    The Recumbent Quant cplager's Avatar
    Join Date
    Jan 2012
    Location
    Norwalk, CT
    My Bikes
    2012 Cruzbike Sofrider, 2013 Cruzigami Mantis
    Posts
    2,906
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by BassNotBass View Post
    . simply awesome!!
    Huh. Somehow awesome isn't the word I would have picked...

    http://Charles.Plager.net
    http://RecumbentQuant.blogspot.com

  13. #13
    Part-time epistemologist invisiblehand's Avatar
    Join Date
    Jun 2005
    Location
    Washington, DC
    My Bikes
    Jamis Nova, Bike Friday NWT, STRIDA, Austro Daimler Vent Noir, Haluzak Horizon, Salsa La Raza, Hollands Tourer, Bike Friday tikit
    Posts
    5,224
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Three derailers?!?


  14. #14
    coprolite fietsbob's Avatar
    Join Date
    Jun 2010
    Location
    NW,Oregon Coast
    My Bikes
    7
    Posts
    3,368
    Mentioned
    50 Post(s)
    Tagged
    0 Thread(s)
    Ah, the humor potential of photo shop ..

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •