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  1. #1
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    New question here. how to tighten sliding dropouts? rear disc brake rubbing..

    Hello,
    I'm riding a Kona Honzo, which has horizontal sliding dropouts:how to tighten sliding dropouts? rear disc brake rubbing..-sliding-dropout-left-exp.jpg

    This is the first bike I have put together myself, so I'm wondering if I did something wrong. The problem is that atm my rear disc brake rubs the pads once every turn. Now, I think that the rotor was already crooked before I even rode my bike (is that even possible??), as I had a hell of a time installing it, while my front brake was immediately ok (using self centering technique). Also, when I lift my rear wheel and give it a good turn, I can see a slight wobble in the disc rotor, while my wheel seems perfectly straight.

    However, it took me almost an hour of fiddling but I eventually got the callipers screwed tight in such a way that the rub wouldn't occur, even though I could still see the slight wobble. But when I go biking, and especially after drops/jumps/hard turns, the rotor starts rubbing again, always once a turn (probably when the wobble passes the pads).
    So I'm wondering, maybe I didn't tighten my dropouts correctly? I just tightened the 2 bolts hand-tight using an allen key, not with my torque wrench, as that seemed enough to hold the wheel in its place. I'm not really sure what the nut and the threaded rod are meant to do? I screwed the rod in until it touched the axle part, and again, hand tightened the nut, not even using a wrench. It doesn't seem to come loose after a ride, but still, the brake rub is always worse when some force is applied to my rear wheel by jumping or turning aggressively.

    Sorry for the long explanation, English is not my first language and I wanted to be clear. I think my question boils down to: how tight do I need to tighten the dropouts bolts, and the nut on the rod?

  2. #2
    AZ
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    The "rod" is the screw and it is there to position the axle and to prevent the axle from sliding forward and the nut that you hand tightened should be gently wrenched tight. Center the wheel in the frame, gently tighten the screws and wrench the jam nuts gently tight. Then you can center your brake caliper. That should keep you rolling smoothly. Good luck.

  3. #3
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    Ok thanks, I called it a rod because it doesn't have a head on my bike, unlike the picture I posted. I tightened it like you said, seems it still occurs though Gonna bring it to my lbs to straighten my rotor next week, I'll see what he says.

  4. #4
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    Quote Originally Posted by Dirty $anchez View Post
    The "rod" is the screw and it is there to position the axle and to prevent the axle from sliding forward and the nut that you hand tightened should be gently wrenched tight. Center the wheel in the frame, gently tighten the screws and wrench the jam nuts gently tight. Then you can center your brake caliper. That should keep you rolling smoothly. Good luck.
    Gently tight, how tight is that exactly?

  5. #5
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    how to tighten sliding dropouts? rear disc brake rubbing..

    Quote Originally Posted by dfuse View Post
    Hello,
    I'm riding a Kona Honzo, which has horizontal sliding dropouts:Click image for larger version. 

Name:	sliding-dropout-left-exp.jpg 
Views:	503 
Size:	59.1 KB 
ID:	813891

    This is the first bike I have put together myself, so I'm wondering if I did something wrong. The problem is that atm my rear disc brake rubs the pads once every turn. Now, I think that the rotor was already crooked before I even rode my bike (is that even possible??), as I had a hell of a time installing it, while my front brake was immediately ok (using self centering technique). Also, when I lift my rear wheel and give it a good turn, I can see a slight wobble in the disc rotor, while my wheel seems perfectly straight.

    However, it took me almost an hour of fiddling but I eventually got the callipers screwed tight in such a way that the rub wouldn't occur, even though I could still see the slight wobble. But when I go biking, and especially after drops/jumps/hard turns, the rotor starts rubbing again, always once a turn (probably when the wobble passes the pads).
    So I'm wondering, maybe I didn't tighten my dropouts correctly? I just tightened the 2 bolts hand-tight using an allen key, not with my torque wrench, as that seemed enough to hold the wheel in its place. I'm not really sure what the nut and the threaded rod are meant to do? I screwed the rod in until it touched the axle part, and again, hand tightened the nut, not even using a wrench. It doesn't seem to come loose after a ride, but still, the brake rub is always worse when some force is applied to my rear wheel by jumping or turning aggressively.

    Sorry for the long explanation, English is not my first language and I wanted to be clear. I think my question boils down to: how tight do I need to tighten the dropouts bolts, and the nut on the rod?
    The rotor rub has nothing to do with the dropouts.

    You need to straighten / true the rotor. Very common problem and easy to fix. Should be able to do it with a clean cloth and your hand.
    mtbtires.com
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  6. #6
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    Somehow I didn't get a notification for the last message, but I came here to tell exactly that. The rotor/pads/dropouts move together so indeed, that couldn't have been the problem. My lbs trued my rotor for free, problem solved! I just couldn't believe that a new rotor could have been, eeuhm, how do you say it in English, un-true?

    I also found out that the screw on my frame can be tightened with a small allen key, I didn't see that at first, and thought it weird that on pictures on the internet like the one I posted the screw has a head. Then I finally understood how this works (or so do I think): I unscrew the two screws on each side, then center the wheel using small adjustement on the larger screws that goes in on the inside. When the weel is centered I 'gently' tighten the four screws and the two nuts. Turns out my wheel wasn't even straight in my frame to begin with! Now my bike runs a lot better.

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