Re-Attaching Front Mech Bracket

Pross
Pross Posts: 43,463
in Workshop
I'm currently having a new groupset fitted to my bike (Scott CR1 frame) and the mechanic doing the work has reported that the existing rivets have corroded and the mech is therefore loose. He has offered to try gluing / re-riveting the mech bracket but isn't confident it will hold and has suggested a specialist frame repair. Given the frame is now over 10 years old and the current problems travelling around I've said to try gluing first and have since read of similar issues including old threads on this site. Has anyone had success re-rivetting and / or using epoxy resins to fix a similar issue? Also, if it fails is it more likely to make a future repair more difficult? I suspect if it doesn't work I might just buy a new frame at some point as getting a repair done is going to be a hassle, possibly expensive and I'll be wondering if other issues are going to arise.

Comments

  • Wheelspinner
    Wheelspinner Posts: 6,692
    Can you not clean it off altogether and just use a band adaptor instead? Or has the down tube got failure issues that also need fixing?
    Open One+ BMC TE29 Seven 622SL On One Scandal Cervelo RS
  • Pross
    Pross Posts: 43,463
    The guy doing it was wary of using a band-on in case the carbon lay up isn't suitable. As far as I'm aware the only damaged area is around the original rivets.
  • me-109
    me-109 Posts: 1,915
    New rivets and glue should be fine. I took mine round to https://fibre-lyte.co.uk/ where they did that to a couple of my cable stops.
  • imposter2.0
    imposter2.0 Posts: 12,028
    edited March 2021
    As above, new rivets should work ok. The other thing to say is that if that part of the seat tube can handle the forces that a braze-on mech will apply, it should also be able to handle a band-on mech for the same reason. The actual clamping pressure that a band-on mech applies is pretty minimal..
  • Pross
    Pross Posts: 43,463
    Thanks all. I've asked him to try re-riveting / gluing and will see how it goes.
  • webboo
    webboo Posts: 6,087
    edited March 2021
    I have an Orbea Orca silver frame from 2012 which has external cables. The cable boss sheared off in 2013 and it went back to Orbea who riveted a new boss on. It had previously been bonded on.
    It still works fine, however I did think they should have replaced the frame under life time warranty but that’s another issue.
    My bike is not kept upside by the way.
  • Pross
    Pross Posts: 43,463
    Well, it has been done so I'll see how it goes. I've had issues with the front mech rubbing for ages (I've hardly ridden the bike for 4 or 5 years) so this probably explains it.
  • david37
    david37 Posts: 1,313
    Ive re done mine Pross, I can send some pictures it was absolutely successful. I bought a new front mech hanger for a cannonade supers hi mod frame. Drilled out the old ones, rubbed back the frame lightly to clean it, lined up the new one and inserted the rivets. To be absolutely sure I also used Epoxy to bond it. Absolutely fine.

    Some frame sprayers remove fittings too and reattach afterward. It is normal albeit not something you are likely to do often even in a bike shop.

    Also make sure your local mechanic is confident and has the right kit and rivets.

  • Pross
    Pross Posts: 43,463
    Cheers, the mechanic left it as it was as he wasn't confident doing it which is fair enough as I'd rather that than someone experimenting and messing up the frame. I can't decide whether to get a burr bit and rivet pliers and try to do it myself or find someone with better skills!
  • elbowloh
    elbowloh Posts: 7,078
    How about a new frame. There's a chap on here who's going to be selling a OnOne Pickenflik soon with just a minor bit of damage...


    😉
    Felt F1 2014
    Felt Z6 2012
    Red Arthur Caygill steel frame
    Tall....
    www.seewildlife.co.uk
  • david37
    david37 Posts: 1,313
    It's daunting but I found it to be straight forward. Take the cranks off and bottom brackets out to get the bits of rivet out after.
    these p


    These pics show the state of it before, during the repair and the finished bit. All done in a garage just like anyone else can.
  • david37
    david37 Posts: 1,313
    sorry the pics are a bit out of order but honestly it was a piece of p ss. I didn't have a bur bit handy so I just used a drill, (carefully so I didn't end up pushing through and out of the tube on the other side :) )
  • david37
    david37 Posts: 1,313
    edited March 2021


    this one is after I rubbed most of the corroded cack off
  • Pross
    Pross Posts: 43,463
    elbowloh said:

    How about a new frame. There's a chap on here who's going to be selling a OnOne Pickenflik soon with just a minor bit of damage...


    😉

    Ha ha, just read that. The thought that someone who fitted the handlebars as they had fancied themselves capable of safely repairing a frame is scary. I'm not great at fixing things, including bikes, but seeing that I'm grateful K realise I'm not great at fixing things!
  • hdow
    hdow Posts: 186
    Thanks david37. Just about to do exactly the same on my Super Six Evo once the bracket turns up. Your comments and pictures are much appreciated. My LBS didn't know it was possible, they do now
  • david37
    david37 Posts: 1,313
    edited March 2021
    hdow said:

    Thanks david37. Just about to do exactly the same on my Super Six Evo once the bracket turns up. Your comments and pictures are much appreciated. My LBS didn't know it was possible, they do now

    yep I actually quite enjoyed it, nothing at all difficult and the end result is banging.

    £20 or a new frame. It's a no brainer really



  • Pross
    Pross Posts: 43,463
    Did you go up a size with the rivets or just match the original?
  • david37
    david37 Posts: 1,313
    edited March 2021
    Pross said:

    Did you go up a size with the rivets or just match the original?

    Original size. they came with the new hanger. I used some epoxy for a belt and braces approach. I drilled out the old ones and was careful not to cracker the holes.

    clean the surface of the frame and the hanger with a bit of very fine sand paper and then alcohol so there's no grease and then apply the epoxy, stick the rivets in so the hanger doesn't fall off and squeeze the rivets. leave for 5 mins for the epoxy to go off and reassemble the bike.

    like I said, daunting only through unfamiliarity but actually quite straight forward.

    As a whole project there were quite a lot of steps but none were too challenging.

    1 remove cranks
    2 remove bottom bracket
    3 remove front mech from hanger and carefully hang out of the way. (this will avoid you having to change the cable)
    4 Drill out the old rivets to remove the hanger.
    5 clean the frame thoroughly.
    6 clean the hanger (new or old) thoroughly
    7 mix and apply a small amount of fast cure epoxy to the hanger base.
    8 offer up the hanger to the frame and keep from falling off with rivets
    9 squeeze the new rivets on ensuring the hanger alignment is correct
    10 re fit bottom bracket
    11 re fit cranks
    12 refit front mech
    13 adjust front mech as required
    14 sit back, with a drink and admire your handiwork

    I used the rivets that came with the mech, I think they were Aluminium. ( but I'm not sure, I just used the ones supplied in the kit)








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