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  1. #1
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    Threaded fork tube length

    I there a ratio or a chart that I can download that will tell me how long the threaded fork tube needs to be for the frame. I bought a bigger frame because my other frame was a little small. I did not get the matching forks with the frame. I know the diameter is not in question. When the cups, bearings are installed is there a length that I need to have sticking out for the remaining hardware? Will thread less forks convert for my older frame.

  2. #2
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    Quote Originally Posted by cncwhiz View Post
    I there a ratio or a chart that I can download that will tell me how long the threaded fork tube needs to be for the frame. I bought a bigger frame because my other frame was a little small. I did not get the matching forks with the frame. I know the diameter is not in question. When the cups, bearings are installed is there a length that I need to have sticking out for the remaining hardware? Will thread less forks convert for my older frame.
    Fork Steering Column Length and Sizing - Park Tool

  3. #3
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    It's impossible to measure, and you would not want to anyway.
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  4. #4
    coprolite fietsbob's Avatar
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    Many Possibilities .. If You have access to the proper Tools or Bought services of those who have invested in the tools,

    I have had my touring bike Fork, made extra Tall and threaded it down Further ,
    and used the extra height via spacers
    and some special Thin Nuts I Had Hoarded (from past shop assemblies that didn't need them)

    to mount a Bell on a Spacer tube and still have plenty of Bar Height ..

    Used a Long Quill stem inserted well into the fork to support the cut thread length.


    If you want to seek out a threadless fork You are welcome to Try,

    Just The Market for 1" threadless forks is past , so the search will be a bit more challenging ..
    Last edited by fietsbob; 09-29-15 at 12:20 PM.

  5. #5
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    It's very straightforward.

    The steerer length measured from the crown seat to the top must be longer than the end to end head tube length by the stack height of the headset.

    You'll find headset stack height data in the headset's spec sheet, or can search using phrases like headset stack height for (model).

    Typically stack heights vary between 33 and 45mm (with exceptions) so if you buy a fork 50mm taller than the frame you'll be fine, and can use spacers or trim it to fit.

    WARNING -- do not buy a fork more than 60mm taller than the head tube. Quality forks only have about 50mm of thread, and if trimmed too much will run out of thread.
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  6. #6
    Old fart JohnDThompson's Avatar
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    For a threaded headset, the steer tube needs to be at least as long as the head tube plus the stack height of the headset. Threaded headset stacks vary in height between about 30mm and 44mm, depending on model. So, don't trim your steer tube until you know what headset you will be using, and it's better to cut it longer than you'll think you need, as you can always use spacers to take up the space. Here are some examples:



    Source: Barnett's Manual

  7. #7
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    [QUOTE=JohnDThompson;18204404]For a threaded headset, the steer tube needs to be at least as long as the head tube plus the stack height of the headset. Threaded headset stacks vary in height between about 30mm and 44mm, depending on model. So, don't trim your steer tube until you know what headset you will be using, and it's better to cut it longer than you'll think you need, as you can always use spacers to take up the space. Here are some examples:



    Source: Barnett's Manual[/QUOTE


    Do you have any for 1 1/8?

  8. #8
    Old fart JohnDThompson's Avatar
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    Quote Originally Posted by cncwhiz View Post
    Do you have any for 1 1/8?
    Not me, but a google search came up with this (in German):


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