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  1. #1
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    Threaded to Threadless

    I just purchased a 1993 stumpjumper fs and removed the non-working fork. Now that Iíve got it out and I am planning on swapping in a threadless fork - do I need to add more to my original steerer tube measurement to accommodate the threadless equipment or can I shop for a new fork with the same steerer tube length?

    Threaded to Threadless-img_1314.jpg

    Thanks for the help

  2. #2
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    Needs to be longer for the stem to clamp on.

  3. #3
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    While what you want to do is not a difficult task, it does require a good understanding of the two systems. I found this video and while it is obviously very dated, is does explain the basic differences between the two types of stems.
    https://www.youtube.com/watch?v=NjjMgPNieyk

    As the video shows, since the threadless stem clamps directly to the steerer tube, a threadless steerer fork will require a longer steerer tube than the fork you currently have. This will also require a different stem and changing the headset as well.

    There are people on this forum that have done what you asking about, on the exact bike you have. Maybe one of them can chime in with details.

  4. #4
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    Thanks for the replies, is there a general rule for how much of the fork tube you want or need sticking out above the head tube?

  5. #5
    Hardtail Steel Forever
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    Quote Originally Posted by Frizzman4 View Post
    Thanks for the replies, is there a general rule for how much of the fork tube you want or need sticking out above the head tube?
    It depends on your stem, but generally 40 - 45mm or so and that would be with zero headset spacers. You basically want the exposed steerer to fit most of the stem clamp height with just a small amount left so the cap can fit on and not be pushed up by the steerer.
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  6. #6
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    When I would install a new threadless setup, I would assemble the whole thing in the repair stand (headset, stem, spacers), make sure it all was seated firmly, then mark the steerer tube at the top of the whole stack with a Sharpie. Then I would pull the fork, and cut it about 3mm below the mark.

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  7. #7
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    Technically from the top of the headset to under the stem, you should not have more than 35mm of headset spacers.
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  8. #8
    Combat Wombat
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    Quote Originally Posted by Frizzman4 View Post
    Thanks for the replies, is there a general rule for how much of the fork tube you want or need sticking out above the head tube?
    If you are buying a new fork that comes with an uncut steerer, then this is not an issue. Buying a used fork that is already cut is where this really matters. Several factors come into play for how long of a steerer tube you will require and can vary considerably from bike to bike. Ultimately what you are looking for, is to end up with your grips at a level you are comfortable with.

    For me and the bikes I ride, I usually run my bars about level with the saddle. First, you need to measure the length of your head tube and this can vary considerable from frame to frame. Taking a quick look at three different bikes in my garage, I measured three different lengths from 90mm to 115mm.

    Averaging steerer length above the head tube, I would say make sure you figure in at least an additional 70mm to the length of the head tube. This leaves room for the upper and lower external headset cups that will be used on a 1993 Specialized, which will be @25mm. Figure in the high side for stem stack height at 40mm. Add a spacer or two and decide what length/angle stem and bars you want.

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