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  1. #1
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    Sliding dropout bent my frame

    I have a 09 Kona Unit 2-9 and I've got an issue with the sliding dropouts. The slot that the sliding dropout slides in has somehow been pryed slightly wider than it should be, causing the dropout to wobble up and down. It used to be nice and tight, in fact when I first adjusted it, it was so tight I could barely move it. The damage is to the non drive side. The drive side is still nice and tight, and I switched drops to make sure it wasn't just the actual dropout itself, but it wasn't, the slot in the frame is widened on the brake side. I would post a picture, but I've already brought the frame to the dealer, and really, you wouldn't be able to see much. It's not really apparent until you grab the dropout and wiggle it and see how much play there is. Its to the point where my wheel is visibly askew, and if it bends any more, my tire will be rubbing the chainstay.

    Has this happened to anyone else out there? I only weigh 155 lbs, but I do ride a lot of very rocky terrain. My rim is fine (stans arch 29), and I haven't crashed the bike badly. I may have brushed against some rocks, but nothing major.

    I'm hoping Kona will warranty it, I'm waiting to see.
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  2. #2
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    Never heard of this happening previously. Good luck, man. I'm betting they'll come through for you.

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  3. #3
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    I do remember seeing this same issue on the 29er board with a steel KHS frame I believe. It ended up being warrantied

  4. #4
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    Quote Originally Posted by boomn
    I do remember seeing this same issue on the 29er board with a steel KHS frame I believe. It ended up being warrantied
    yes, always to the disc side.

    this is the first i've heard of a 2-9 though but it makes sense, both used a similarly minimalist slider system.

    i think you'll see warranty help.
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    Quote Originally Posted by nogearshere
    yes, always to the disc side.

    this is the first i've heard of a 2-9 though but it makes sense, both used a similarly minimalist slider system.

    i think you'll see warranty help.
    Yes, their's and a few others have some really petite lookin sliders....I've wondered about this exact problem with them. My Speialized Rockhopper 29er sliders are larger and I (knock on wood) haven't had any problems with them as long as they are torqued to spec.
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  6. #6
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    Quote Originally Posted by Natedogz
    Yes, their's and a few others have some really petite lookin sliders....I've wondered about this exact problem with them. My Speialized Rockhopper 29er sliders are larger and I (knock on wood) haven't had any problems with them as long as they are torqued to spec.
    couple things.
    material - aluminum sliders tend to be more beefy, thicker to begin with...builders are 'used' to overcompensating for aluminum (myself included). there can be a false sense of security when using steel.
    location - when the axle and mount extend way past the chainstay and seatstay 'joint' there are some serious forces at work. smart builders of lower-end (not intended as an insult) chromoly have relocated the disc mount to alleviate the forces (on-one for example).
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  7. #7
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    The problem is in the forces used by the disc brake. It leverages one bolt up and the other down. That's one thing nice about Paragon sliders. They don't just have the bolts. They have a long piece of material in the groove to spread out the load. They do typically require a bridge between the seat and chain stays.

  8. #8
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    Seat/chain stay bridge - kinda like this?

    Saw this on History Channels Monster Quest...

    Quote Originally Posted by Schmucker
    The problem is in the forces used by the disc brake. It leverages one bolt up and the other down. That's one thing nice about Paragon sliders. They don't just have the bolts. They have a long piece of material in the groove to spread out the load. They do typically require a bridge between the seat and chain stays.
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  9. #9
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  10. #10
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    Quote Originally Posted by nogearshere
    couple things.
    material - aluminum sliders tend to be more beefy, thicker to begin with...builders are 'used' to overcompensating for aluminum (myself included). there can be a false sense of security when using steel.
    location - when the axle and mount extend way past the chainstay and seatstay 'joint' there are some serious forces at work. smart builders of lower-end (not intended as an insult) chromoly have relocated the disc mount to alleviate the forces (on-one for example).
    Agreed.
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  11. #11
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    I had the same thing happen to my KHS. I temporarilly fixed it with some spacers I made from a cut up aluminum can. The frame ended up cracking in a different spot so I got a new one under warranty. The new one has an extra vertical tube in the rear triangle on the brake side, seems to stiffen it up a bit. Time will tell if it alleviates the issue.

  12. #12
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    Hmm, wonder if I should be worried about running 8" discs on my 09 unit.

  13. #13
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    Quote Originally Posted by maxtheheathen
    Hmm, wonder if I should be worried about running 8" discs on my 09 unit.
    I use a 203mm on front and a 160mm on the rear.

    My buddy uses 160 front and rear on his 29er.

    I don't think there's any real need for a 203 in the back unless you're a downhiller.

  14. #14
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    Quote Originally Posted by nogearshere
    location - when the axle and mount extend way past the chainstay and seatstay 'joint' there are some serious forces at work. smart builders of lower-end (not intended as an insult) chromoly have relocated the disc mount to alleviate the forces (on-one for example).
    My dropout was also set up so that the back end of it(rear screw) was just past halfway along the slot, so that any leverage pressing up was pushing at probably the weakest point, as you can see that the further along the slot, the less steel there is.

    The dropout was about a quarter inch further back than when this was taken, you can faintly see a mark in the steel. That's about where it was set when it bent.

    2009 Kona Unit 2-9 sliding dropout
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  15. #15
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    Quote Originally Posted by icecreamjay
    My dropout was also set up so that the back end of it(rear screw) was just past halfway along the slot, so that any leverage pressing up was pushing at probably the weakest point, as you can see that the further along the slot, the less steel there is.

    The dropout was about a quarter inch further back than when this was taken, you can faintly see a mark in the steel. That's about where it was set when it bent.

    2009 Kona Unit 2-9 sliding dropout
    spreading those bolts apart (on that design) would work wonders too.
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  16. #16
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    They're paragon sliders, right? The older units had a different slider that was much beefier.

    As far as the 203 rotors, yeah they're overkill, but i ride some really long, twisty, crowded descents, and like that they don't get too hot and fade.

    I haven't heard of any problems with paragons other than some people having them slip.

  17. #17
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    Well the good news is that after 6 days and another email, Kona has responded. They've decided that a new slider assembly is the answer.

    Well I already tried the drive side one and it doesn't fit properly. Unless the slot on the brake side is supposed to be slightly ovalized and they make a magical slider that can expand and contract depending on where in the slot its located I can't see how it will help. At least if this doesn't work (and I really can't see how it possibly could), they will be forced to accept that something is wrong with the frame.

    So Friday the part should be in and we'll see. Hopefully this whole deal doesn't take much longer, as I really miss my 29er.
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  18. #18
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    There were some posts on the Dirt Rag Forum about steel KHS SS frames with the same sort of problem, the guy had two frames in a row develop the problem. He switched to a Misfit diSSent and as the saying goes "lived happily ever after".

    http://www.dirtragmag.com/forums/sho...5&postcount=21
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  19. #19
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    Quote Originally Posted by nogearshere
    spreading those bolts apart (on that design) would work wonders too.
    Yes, these 2 bolts are way too close together and that slider is mighty thin!

    Quote Originally Posted by icecreamjay
    Well the good news is that after 6 days and another email, Kona has responded. They've decided that a new slider assembly is the answer.

    Well I already tried the drive side one and it doesn't fit properly. Unless the slot on the brake side is supposed to be slightly ovalized and they make a magical slider that can expand and contract depending on where in the slot its located I can't see how it will help. At least if this doesn't work (and I really can't see how it possibly could), they will be forced to accept that something is wrong with the frame.

    So Friday the part should be in and we'll see. Hopefully this whole deal doesn't take much longer, as I really miss my 29er.
    Good luck....swap the parts like they want and when it doesn't work, call them again. I'd get some good caliper measurments of the slot width at equal intervals along it's entire length while you have it apart...should easily prove the problem. Oh and a good clear pic of both slots without the dropouts in place!

    Quote Originally Posted by rockyuphill
    There were some posts on the Dirt Rag Forum about steel KHS SS frames with the same sort of problem, the guy had two frames in a row develop the problem. He switched to a Misfit diSSent and as the saying goes "lived happily ever after".

    http://www.dirtragmag.com/forums/sho...5&postcount=21

    Wow, that is beyond fawked up! =P
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  20. #20
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    Yay!

    I got another email from the shop today, and Kona has decided to ship a new frame!
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  21. #21
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    Quote Originally Posted by icecreamjay
    I got another email from the shop today, and Kona has decided to ship a new frame!
    Congratulations, glad that they are finally going to take care of you properly! Hope the new frame is beefier/better design.
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