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  1. #1

    Join Date
    May 2016
    Posts
    2

    Default 33.4 front end issues!!

    Hey guys I'm in need of some desperate help. just cant get my head around my front end set up.

    I'm currently running 10" over tubes and a hamburger drum hub.

    Up until recently I didn't have a brace and everything was fine. when I did find the much needed brace to help control the front end, thats when everything fell apart.

    When I fitted the brace over six months ago it felt solid and that the forks were working correctly and the wheel fitted up perfectly.

    However I recently did a check up on the entire bike to realise that something seriously wrong is going on and that my fork lowers have managed to pull in to tightly somehow and have literally carved my hub up so bad that on every revolution of the wheel leaves more and more alloy shaving on my bench

    Now the most obvious problem would appear to be the brace and thinking that the width between the tube holes is narrower but as I can slide the brace right up under the lower tree this quickly rules that out. But as you can see from the photos theres a MASSIVE taper running from my lower tree all the way down to the axel and I don't know whats going on.

    If it is some how the brace then I'm wondering if there are different width trees over the years and maybe the brace is from a different front end?

    Im also finding it hard to get my head around why the forks would taper so much from the trees down to the hub as well as this dosent seem right either...

    Could I be missing a spacer or something to pull the forks apart so their not so hard up against the hub?

    Any help is greatly appreciated!

    Thanks
    Saxon
    Attached Thumbnails Attached Thumbnails IMG_3241-1.JPG   IMG_3255-1.JPG   IMG_3252-1.JPG   IMG_3251-1.JPG   IMG_3244-1.JPG  

    Last edited by seeny; 04-18-2019 at 11:30 PM.

  2. #2
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    Join Date
    Dec 2017
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    2,093

    Default

    Poor hamburger...ya, a big taper, from 5.300" at lower tree to 5.011" at tweek bar...289 thou, like over 1/4"!
    Seems like the wrong tweek bar - too narrow. Did you remove a wheel spacer? Take off tweek bar, check legs for parallel and straight, check lower legs for play due to bushing wear. Check neck bearings for looseness, lube and adjust tension. Confirm all is straight, legs parallel, lower legs have proper sliding clearance, then check wheel fit, center it, and add axle spacers.

  3. #3
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    Sep 2010
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    Hub internal bearings/spacers screwed ... ??

  4. #4

    Join Date
    Dec 2018
    Posts
    856

    Default

    Like all these HD front ends, one leg floats on the axle, and is clamped in place by the assembler. So it's YOU who determines whether the fork legs are parallel when YOU assemble it.

    Drag is on to something with his idea about internal damage. I have had that experience myself. The steps inside the hub that locate the bearing OD is thin, and can be battered or worn away over time. I have had to add a shim or ring to bring the bearing back to its proper location. And that bearing location being off will result in the damage pictured.

    Jim

  5. #5

    Join Date
    May 2016
    Posts
    2

    Default

    Thanks Jim but how do I control how parallel the fit up is when the forks are tapering well before the wheel and axel are even installed?

    I will have to pull the hub apart and examine it but I fear it’s already toast and will need to source another.

    I’m still concerned with the forks though as the taper seems way too extreme. I’ll have to take the tweak bar off and see if that resolves it. If so I will have to look at getting a new one made up as i have no more patience sourcing braces just to find that their the wrong width.

    If there is damage to the internal parts of the hub then it would make sense that the brace is pulling the forks in too tight at the axel/hub and has put too much pressure on the spacer and bearings etc and have now failed causing the hub the rub on the lowers?!

  6. #6

    Join Date
    Dec 2018
    Posts
    856

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    From your pictures, it appears that your tweak bar is pulling the fork tubes together when clamped. It will not do this when you shove it up to the lower tree because the lower tree is holding the tubes in place. Measuring with those calipers is problematic because the nibs don't appear to reach the centerline of the tube.

    I think your tweak bar is the culprit. But a disassembly of the hub is in order, for safety's sake if nothing else.

    Jim

  7. #7
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    Quote Originally Posted by seeny View Post
    Thanks Jim but how do I control how parallel the fit up is when the forks are tapering well before the wheel and axel are even installed?

    I will have to pull the hub apart and examine it but I fear it’s already toast and will need to source another.

    I’m still concerned with the forks though as the taper seems way too extreme. I’ll have to take the tweak bar off and see if that resolves it. If so I will have to look at getting a new one made up as i have no more patience sourcing braces just to find that their the wrong width.

    If there is damage to the internal parts of the hub then it would make sense that the brace is pulling the forks in too tight at the axel/hub and has put too much pressure on the spacer and bearings etc and have now failed causing the hub the rub on the lowers?!
    get a 33.4 original lower tree, take your cut off wheel and hack the back off where the stem is, dress it up by smooting some stuff out and you have the perfect brace. second from the front of the bike the left lower, the hole where the axle slide through, exam the diamter of the hole to the outside diameter of the axle, you may need to turn down a bushing insert for that hole on a lathe

  8. #8
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    When you mount the front wheel make sure you do not squeeze the forks together OR spread them apart to make everything fit!
    Make sure to use a thickness gauge if needed to get the proper thickness spacers.

    That rubbing up against the bearing is because the wheel outer spacer is not long enough.

    The fork brace if correct should fit on the TOP of the forks. Check that out.
    Attached Thumbnails Attached Thumbnails Front-view.jpg  
    Last edited by Luky; 04-22-2019 at 10:52 AM.

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