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  1. #1
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    New question here. Using a 26" Fork on a 20" Wheel Frame?

    I am definitely needing a better fork for my daughter than the Spinner fork on there now, as it doesn't move much, even with me pushing down on it, and still weighs in the 3-4 pound range. My daughter has a Specialized Hot Rock 20" wheeled frame, and I mounted a Shimano XT disc brake on the Spinner, with a stem with a decent amount of rise and carbon riser bars.

    What I would like to do is put a small travel fork that will actually move with her weight (45#). She is starting to ride downhills pretty quickly now, but everytime she hits a rock/bump, the Spinner doesn't deflect at all. So I would keep the 20" wheel on for now, so I would ideally move her handlebars up 3" with the 26" wheeled fork. I could hopefully negate half or more of that rise by removing the spacer under the stem, putting on a different stem (or flipping it) and either getting flat bars or flipping the bars too. I would then pad up the steerer tube / stem area, and she already wears a full face helmet and armour. Can anyone else see any problems with this safety or bike handling wise? I know the head tube angle will slacken a bit, but enough to be worried?

    Can anyone recommend any decently lightweight, fairly short travel air forks that can be tuned for a 45 pounder? I was looking at the older Rock SID 63mm forks, as they supposedly weigh less than 3#. So I would be getting a more supple fork that weighs less and is useable later down the road, sounds like a win-win-win to me.

    Thanks for any help - BS

  2. #2
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    I think you'd be far better off just going to a properly sized rigid fork w/ a high volume tire at low pressure. Won't look as fancy, but will work a lot better. Depends on your priorities - I know lots of people like to tinker with this type of stuff mainly for tinkerings sake, but I really doubt you're going to see any actual performance gain from a suspension fork at her size/age.
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  3. #3
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    Raising the front-end by 3" will also make the head-tube angle and the seat tube angles get slacker by almost 3. This is a huge change of geometry and can result in very wonky handling/steering characteristics and change the fit relationship between the seat and the bottom bracket. The bottom bracket and seat will also get raised upward by about 1.5" so makes it more difficult for kid to reach the ground.
    I would recommend first working on the 20" spinner for you already have, see if you can change out the springs to lighten the action. If there are springs in both legs, removing them from one side will reduce the spring rate by 1/2 and also reduce a bit of weight. You can also source springs from other forks or generic springs from hardware store that are lighter spring rate than the ones currently in the fork.

  4. #4
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    There's a number of ways to address your problem.

    I'd suggest putting an unmodified 26" fork onto the bike is not one of them.

    There are some people who have found 26" forks that can be cut down to work with 20" geometry, but I think the actual forks are few and far between.

    I started tinkering with this idea as well, although my daughters bike is currently rigid. Then I realized she's going to outgrow this bike pretty quick, and decided it wasn't a good way to spend money.

  5. #5
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    I use the same method that Slaphead recommended. I bought a beefier front tire and run it at a lower tire pressure. No complaints.

  6. #6
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    My daughter has a 2.3" tire on the front, run at fairly low psi (any lower and she will get rim strikes and pinch flats). I know it is a lot of money for a bike she will only ride probably the rest of this summer for, but I have a younger son who will get two years with it, and then will pass it down to my brother who has a son who will get two years out of it, so it's worth it to me.

    Does anyone know of a source for a good lightweight rigid fork for a 20" wheel that has disc brake mounts? If she isn't getting anything from the Spinner, might as well lose a pound or two.

  7. #7
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    I personally would again un-complicate things and forget the disc brakes, unless you guys are DHing regularly. It seems to me that a kid would really need to riding at a pretty high level for them to make any real difference beyond aesthetics.
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  8. #8
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    I would agree for 75% of the rides we do, getting rid of disc brakes would be good, but there are several 3,000 foot climb then 3000' downhills that we do, with the goal to do some 5k climb/downhills this year. The first time we did this ride, my daughter was in tears because her forearms and hands were cramping and it was dangerous as a couple times she couldn't stop when she needed to. We had to stop every couple of minutes and massage out her arms. I bought the XT brake for her front the next day, and we went down only stopping for food and drink a couple weeks later, with her having the biggest smile on her face. And yeah, she does like having the same brakes as mom and dad, but I would never put anything on her bike that brings heaviness without a substantial function.

  9. #9
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    Quote Originally Posted by Garasaki View Post
    There are some people who have found 26" forks that can be cut down to work with 20" geometry, but I think the actual forks are few and far between.
    I have a shortened manitou on my daughters 20". Novara Pixie 20" project
    Deal breaker here is that I doubt that there is any 26" fork that can so easily be shortened AND which has disk brake mounts. Only possible solution I can envision would be to fabricate a clamp-on brake mound sleeve can be added to left slider tube.

    Might also be interesting to try re-using just the sliders from the 20" spinner fork, rebuilding everything else with parts from a decent 26" fork (or custom fabricated parts) so as to replace the spinners crown, stanchions and springs with nicer, lighter weight parts.

  10. #10
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    Quote Originally Posted by BullSCit View Post
    there are several 3,000 foot climb then 3000' downhills that we do, with the goal to do some 5k climb/downhills this year.
    Sounds advanced enough for discs to me! That's awesome.

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