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Griffon hub repair

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  • Griffon hub repair

    Hi guys, I'd be grateful of a little advice. At Maylandsea a couple of weeks ago I had a freak occurrence. Brake pedal came loose and momentarily wedged itself between the swing arm and rear hub. Hub came off worse with the flange that holds the spokes being smashed. pic 2. I guess I was lucky to get back in without the back wheel collapsing - I thought I had just being clipped from behind by another rider so carried on to the end of the race.

    Asking around the paddock, the jury was out as to whether this is repairable ( or cost effective to repair) and who would have the expertise / willingness to have a go. Your thoughts appreciated.

    I do have another rear wheel but the brake lining has a chunk broken off. pic 1. So again, is this worth the cost of repair, given the spokes and rim would also need replacing ( or swapping from the original wheel). I've drawn a blank trying to find someone who can replace this lining so if anyone can recommend where I might get this done, I'd be grateful

    Or the easier option, does anyone have a spare griffon rear wheel or hub they would be willing to part with?

    Cheers in advance,

    Paul

    You may only view thumbnails in this gallery. This gallery has 2 photos.

  • #2
    Forget it paul, they are both scrap, for your own safety, please do not try & have these repaired!
    source a replacement, try tds, or others......

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    • #3
      Ouch! thanks for comment Dave. I was pretty sure the broken flange was un-repairable but had hopes for the other hub. I thought these drum linings were just pressed in so should be replaceable. But I've also heard some are cast-in which means they are not. I cant tell if mine is pressed in or cast in. I saw Terry on the day and he was going to try and find me a hub - I will give him a nudge.
      How you doin' by the way....

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      • #4
        I would repair both to use myself. Boring the brake liner out is not a big job and most engineering shops should be able to do this with the rim still on. I usually find a hub with a similar sized liner and machine that from the hub rather than turning up a new one.
        The spoke flange could be copied and sweated back on halfway along the hub. I made a hub for my tri grieves and used this technique. When in full 500 size and using twin carbs it would be producing more power than the griffin and stood the test of time

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        • #5
          I have re-linered a Griffon hub which had a cracked liner. I did it just to see if I could. The hub is cast around the liner which has projections, so there is a fair bit to machine away. I then got a suitable size piece of steel tube and machined it to be a shrink fit and pegged it.
          If you pay a machine shop the going rate it's just not worth it, perhaps if it was the only Griffon hub on the planet it might be. Put it in the scrap aluminium bin, the chances are that the bearing housing is knackered anyway, but there is a solution to that.

          Druid..

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          • #6
            Thanks guys, its comforting to know that there is help out there from people with top draw engineering skills and with first hand experience of doing this themselves. For folk like me whose precision engineering skills amounts to hitting stuff with a big hammer, your advice is priceless.

            I talked to a chap who advertises in one of the classic mags today, and among other engineering services offered, he does machine out and replace liners. I expected it to cost more than the hub was worth, but he gave me a ball park figure and it was considerably less than I expected. Certainly less than a second hand hub would be (which could also require some work). I'm in a difficult position here as I don't want to sit out the rest of this years Greeves Championship waiting for a hub to become available, so I think I will talk again with the chap and see how we go.

            Druid, just so I'm clear, you mention the liner has projections. Is it necessary to machine these right out? I would have thought you need to keep as much of the meat on the hub as possible, even if this meant leaving some of the liner projections in the hub?

            Paul

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            • #7
              Paul,
              When you machine the liner these projections become loose, I wanted a close contact between hub and liner so I felt happier machining them out to give a tight parallel bore, it still leaves enough meat in the hub.

              Druid

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              • #8
                Fair enough John. Just got off the phone with Dave Harper who explained the projections are more like small splines on the outer face of the liner. I had imagined they were more like blisters which indented several mm. It all makes more sense now, cheers.

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                • #9
                  Paul, Did you fix this ? I have a rear conical where the brake liner has come away slightly - so not sure who to approach -Paul A suggested machine it out, Sam H is more for welding without removing? But he hasnt seen the wheel yet- I will pesonal message you

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