Mono Shock Spherical Bearings

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by Hockenrider, Feb 20, 2012.

  1. Hockenrider

    Hockenrider Wheel in Front

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    Could any one tell me whether they have used another Brand or found another source of Spherical bearings to replace the listed KTM Bearing repair kit's (R12013- R12012 ) for the Rear mono shock .

    Looking for upper and lower bearings to be replaced.

    Checking first before I pull these out and maybe damage them and then not being able to use the beast.

    Issue here is the time waiting for these to arrive EX KTM.

    Cheers In advanced.
    #1
  2. EZ300

    EZ300 Just wanna ride my motorsickle

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    I need the same information...


    BUMP
    #2
  3. EZ300

    EZ300 Just wanna ride my motorsickle

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    ..... no replies leads me to believe the only option is a stock replacement part.
    I sure was hoping Synergy Seals or someone had something for this application similar to the x bushing.
    #3
  4. uk_mouse

    uk_mouse Aquatic adventurer

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    I'm bringing this thread back from the dead, as I was about to post a very similar question.

    Basically, these spherical bearings in the shock don't seem to last very well. Probably dirt or water is getting in, especially to the lower one, but mine seem to wear out in less than a year. Replacement parts from KTM aren't cheap, but the dimensions of the bearings are not standard so my attempts to find a 3rd party replacement have failed so far.

    Also I have a problem with the rear suspension 'binding'. Some days it feels super plush and responsive, and some days it feels as though something is sticking and the shock isn't compressing properly. I've just had the shock serviced so it's not the unit itself. And the swinging arm moves totally freely (but no play in bearings) when the shock and wheel are removed.

    So I'm left to concluse that the problem is the spherical bearings sticking. After all, they are dry bearings with just a thin layer of PTFE (I think) for lubrication. And if I remove the bearings, clean them as best as I can, and spray a bit of silicon lubricant in there, it does seem to improve matters, for a short time. That's not a long term solution though.

    So I'm wondering - has anyone got ideas for an alternative? Either an alternative spherical bearing that lasts better, or something totally different?

    If Powercell is reading this, what do you use in your aftermarket uber-shocks, please?

    Thanks for any advice :)
    #4
  5. PowerCell

    PowerCell Manufacture

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    We use a special SKF spherical bearing for this very reason. It's much larger, requires our special bushings, and is not compatible with the factory shock...


    [​IMG]

    .
    #5
  6. Hockenrider

    Hockenrider Wheel in Front

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    #6
  7. uk_mouse

    uk_mouse Aquatic adventurer

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    Powercell - thanks for the info, shame the bearings are not compatible!

    Hockenrider - the trouble is they seem to wear out so fast. And from KTM those bearings are not cheap. I'm still searching for an alternative, if I find anything I will share the info.
    #7
  8. gefr

    gefr Life is a trip

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    So I can follow? I recently had the rear suspension refurbished...
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  9. uk_mouse

    uk_mouse Aquatic adventurer

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    A spherical bearing isn't a ball bearing, they look like this:

    [​IMG]


    The ones we are referring to are parts 5 and 89 in this diagram. #89, the lower one, is the one that fails most for me, presumably as it gets more dirt in it.

    [​IMG]
    #9
  10. wcohl

    wcohl Been here awhile

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    #10
  11. uk_mouse

    uk_mouse Aquatic adventurer

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    Yes I've found a similar item on ebay, intended for steering rod ends. I'm not sure if the size is totally compatible as I've lost my notes of the OEM bearing sizes! :(

    The SC16 bearing wcohl mentions is 16mm ID, 32mm OD - which is the same as the KTM lower bearing part. The dimensions I'm not sure of are the bearing outer shell depth, and inner ball depth (labelled B and C on the page linked above). Anyone have these measurements to hand for the KTM part please?

    The OEM upper bearing is 15mm ID, 25mm OD which doesn't appear to be a standard size and I've never seen one in any of the catalogues I've loooked at. But this part fails less frequently in my experience.

    What might be really good would be to fit one of the aftermarket parts (if they fit) without the teflon liner, and then also fit a grease nipple - but I'm a bit reluctant to go drilling holes in my shock absorber.
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  12. wcohl

    wcohl Been here awhile

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    uk,

    The B and C dimensions from Hirschman are the same as KTM dirt bikes. I've never had one of the bigger bike heim bearing out, but I doubt they are different.

    I've never tried to find a replacement upper bearing, but I would think KTM/WP used a standard size and not a proprietary baering.
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  13. PowerCell

    PowerCell Manufacture

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    I should have mentioned this before, but yes, they are the same as on the top end of the smaller bikes. It's just the 14mm bushings that vary... :thumb


    .
    #13
  14. uk_mouse

    uk_mouse Aquatic adventurer

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    I've now checked the size of the lower bearing, and this item from ebay looks like it will be compatible. I've ordered one to try out, I'll report back.

    http://www.ebay.co.uk/itm/160932377783

    For future reference, the lower bearing dimensions are:

    Inside diameter: 16mm
    Outside diameter: 32mm
    Shell width: 15mm
    Ball width: 21mm

    I've yet to find a match for the upper bearing.
    #14
  15. sproot

    sproot Sturdy Adventurer

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    I just bought that bearing, it fits, don't know how long it will last but it was an improvement over the seized original!
    I couldn't find a match for the top one either, ended up getting the KTM OE part, for a small fortune, which was mildy annoying because the top one wasn't seized.
    #15
  16. uk_mouse

    uk_mouse Aquatic adventurer

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    I might be fitting my ebay bearing later today too - I fitted a KTM replacement earlier this year and it feels like it's developed a bit of play already :( Side by side the ebay part and KTM part look identical.
    #16
  17. uk_mouse

    uk_mouse Aquatic adventurer

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    Here's another possibility - anyone fancy trying a plastic bearing? Part number KGLM-16 from this page: http://www.igus.co.uk/wpck/2493/igubal_Gelenklager_KGLM_mm

    It's not nearly as strong as the metal version ... radial load of 8000 N compared to (allegedly) 90,000 N. That's still equivalent to about 800kg though.
    #17
  18. gefr

    gefr Life is a trip

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    That is still 1/10 th of the OEM strength. I wouldn't like to be too far off. I suppose some engineers designed this for a reason.
    Cheers.
    #18
  19. uk_mouse

    uk_mouse Aquatic adventurer

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    Indeed - I might do some calculations to estimate the force through the shock sometime.

    I've just had my bike in bits (again) and measured the top shock bearing, for completeness. The dimensions are:

    Outer diameter: 25mm
    Inner diameter: 15mm
    Ball width: 13mm
    Shell width: 12mm
    #19
  20. LWC3077

    LWC3077 Adventurer

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