Advertise on Bikeforums.net



User Tag List

Results 1 to 8 of 8
  1. #1
    Senior Member d2create's Avatar
    Join Date
    Apr 2003
    Location
    Houston we have a problem
    Posts
    2,913
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    half link adds 2" of chain slack?

    Before I added the half link my chain was very taught with maybe a quarter inch of movement if I lifted or pressed on it. Then by just adding the half link there is way too much slack... At least 2"! Never expected to get that much. Would going from a 48t ring to a 47 give me that much slack?
    2008 Rivendell A. Homer Hilsen
    Pics and Specs Here!

    2010 Specialized Rockhopper 29er

  2. #2
    Numbnuts
    Join Date
    May 2005
    Location
    Bozeman, MT
    My Bikes
    KHS 555, Trek 820 converted to cruiser/winter bike, Trek 520 singlespeed conversion.
    Posts
    128
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Apparently so.

    Is this your IRO?

  3. #3
    You Know!? For Kids! jsharr's Avatar
    Join Date
    Apr 2005
    Location
    Just NW of Richardson Bike Mart
    My Bikes
    '05 Trek 1200 / '90 Trek 8000 / '? Falcon Europa
    Posts
    6,013
    Mentioned
    10 Post(s)
    Tagged
    3 Thread(s)
    did the two things occur at the same time. You decreased the size of your front ring and lengthened your chain? If so, then yes, it may well could.
    Are you a registered member? Why not? Click here to register. It's free and only takes 27 seconds! Help out the forums, abide by our community guidelines.
    Quote Originally Posted by colorider View Post
    Phobias are for irrational fears. Fear of junk ripping badgers is perfectly rational. Those things are nasty.

  4. #4
    Senior Member d2create's Avatar
    Join Date
    Apr 2003
    Location
    Houston we have a problem
    Posts
    2,913
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by jsharr View Post
    did the two things occur at the same time. You decreased the size of your front ring and lengthened your chain? If so, then yes, it may well could.
    No.
    All i did was add the half link.
    So what I'm wondering is if going one tooth smaller on the front chain ring (and removing the half link) will make as drastic of a difference?

    And no, this is not the IRO.
    2008 Rivendell A. Homer Hilsen
    Pics and Specs Here!

    2010 Specialized Rockhopper 29er

  5. #5
    Senior Member BCRider's Avatar
    Join Date
    Mar 2008
    Location
    The 'Wack, BC, Canada
    My Bikes
    Norco (4), Miyata, Canondale, Specialized, K2 Proflex
    Posts
    5,359
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Yes that sounds about right to me.

    Think if it in terms of triangles. Draw a long but shallow equilateral triangle with a long flat base and two equal upper parts with a 1/4 inch of center height. Now measure the lengths of the two equal upper sides. Then add 1/4 inch to each upper side and arc them up from the ends until the inner ends meet again. You'll be amazed at the "slack" you'll see.
    Model airplanes are cool too!.....

  6. #6
    `````````````` CaptainCool's Avatar
    Join Date
    Feb 2007
    Location
    san jose
    Posts
    765
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    If you're running SS/fixed on a bike with vertical dropouts, there's a more elegant way to find the magic gear combo for your bike.

    Quote Originally Posted by BCRider View Post
    Yes that sounds about right to me.

    Think if it in terms of triangles. Draw a long but shallow equilateral triangle with a long flat base and two equal upper parts with a 1/4 inch of center height. Now measure the lengths of the two equal upper sides. Then add 1/4 inch to each upper side and arc them up from the ends until the inner ends meet again. You'll be amazed at the "slack" you'll see.
    Yep. To run some numbers:

    Assuming a 17" chainstay, in half is 8.5". Half of a half link is 0.25", meaning there's 8.75" of chain for 8.5" of chainstay. Pythagoras says that means about sqrt(8.75^2 - 8.5^2) = 2.1" of extra vertical slack.

  7. #7
    Senior Member d2create's Avatar
    Join Date
    Apr 2003
    Location
    Houston we have a problem
    Posts
    2,913
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by CaptainCool View Post
    If you're running SS/fixed on a bike with vertical dropouts, there's a more elegant way to find the magic gear combo for your bike.
    Is this what you mean?
    http://eehouse.org/fixin/javafmu.php

    I ran the numbers and it says I need one tooth less on the big ring which is why I'm asking if that will make as big of a difference as that half link. I sure hope not.
    Just trying to double-check before buying a new ring.
    2008 Rivendell A. Homer Hilsen
    Pics and Specs Here!

    2010 Specialized Rockhopper 29er

  8. #8
    `````````````` CaptainCool's Avatar
    Join Date
    Feb 2007
    Location
    san jose
    Posts
    765
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by d2create View Post
    Is this what you mean?
    http://eehouse.org/fixin/javafmu.php

    I ran the numbers and it says I need one tooth less on the big ring which is why I'm asking if that will make as big of a difference as that half link. I sure hope not.
    Just trying to double-check before buying a new ring.
    Yes, that's the calculator.

    I think one tooth on the chainring will be about half as much change as adding or removing a half link. There will be about half a tooth difference in the amount of chain touching the chainring.

Posting Permissions

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