Broken Front Deraileur Hanger --- What next?

embertr
embertr Posts: 3
edited January 2012 in Workshop
Hi,

While searching for the answer to the topic of this post I came across this wonderful site. Lots of very interesting posts here. I have a Bianchi Reporto Corse road bike, which is an aluminium frame. The front deraileur hanger is broken and I'm not sure if this can be repaired or I should look to grind it off and attempt a clamp on hanger. Anyone have any experience with this type of thing? The metal in the hanger appears as well to be some kind of alloy so until I hear back from a Bianchi representative I'm at a loss. Just want to get this bike back on the road but not really interested in it as a fixey!

Thanks for any advice in advance.

Bob

Comments

  • John.T
    John.T Posts: 3,698
    Before you do anything is the bike out of warranty. If not try that first.
    Any repair will damage the paint so you are looking at a respray after welding. Easiest is to carefully grind the broken part off making sure to get it level with the tube and then use a band-on mech. You should only need a small amount of touch up for this.
    My Fleet.
  • embertr
    embertr Posts: 3
    Thanks John T.

    I've been reading about some "glue-like" weld compounds and I was thinking if I add a stronger metal on top of the alloy and "glue-weld" it all together that maybe that would work to hold everything in place. My fear about grinding and going to a clamp-on is that I might mess up and put a gouge in the tube. Anyone know about these weld replacement compounds?

    Thanks.
  • desweller
    desweller Posts: 5,175
    I'd stick to hand tools doing a job like that. The tubes are pretty thin.
    - - - - - - - - - -
    On Strava.{/url}
  • Yossie
    Yossie Posts: 2,600
    The glue weldy stuff is trash - absolute waste of time. Does nothing but waste your time and money.

    As above: Dremel or hand file, take the old bracket down, band on on top.

    If the frame is precious to you, take it to a frame building dude for repair/the above. .
  • rjsmith
    rjsmith Posts: 1,924
    Is the FM hanger definately welded on? Some are riveted on or have tiny bolts that hold it in. I'd get a proper frame builder to do it for you as it's a nice frame.
  • Monty Dog
    Monty Dog Posts: 20,614
    The problem is that with an aluminium alloy frame, the tube is pretty thin at this point and therefore using any form of power tool could end is disaster. It may be possible to reweld the bracket provided it is cracked on the bracket portion otherwise you risk blowing a hole in the downtube if trying to weld to that. If the frame tubes are heat treated then any localised welding could leave a weakness for later. Safest option would be to use handtools to cut/file the remnants of the bracket flush and use a clamp-on adaptor - filing the inside of the clamp band to accommodate the remnants of the brackets is worth considering too
    Make mine an Italian, with Campagnolo on the side..
  • Lookyhere
    Lookyhere Posts: 987
    It is possible that the frame material at the weld is very thin and not up to having a band on clamp around the down tube or thats what they would have done in the first place? the welding could have weakened the tube further if you grind it off ?
    Surely the best thing is to contact a frame builder and ask them... Brian Rourke or Argoscycles in bristol.
    http://www.argoscycles.com/ they repaired my frame and it was superb could nt tell it had been done.
  • Yossie
    Yossie Posts: 2,600
    If you're still worried about the strength of the frame under the band, get one slightly too big and use a shim a couple of mm bigger than the band underneath (ie so it sticks out above and below the band) - this will support and spread the load.

    If you paint it the same colour as the frame before you put it on then no one will notice its there and it will give you peace of mind.

    But, as I said earlier, a frame builder is always an option.

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