Fixing a bent mech hanger?

APIII Posts: 2,010
edited May 2009 in Workshop
Ok, so I've got an old steel bike that has a bent rear hanger. What is the best way to straighten it without damaging the paintwork? I took it to my lbs, but they didn't want to touch it


  • nicklouse
    nicklouse Posts: 50,675
    find an old shimano hubed wheel with a threaded axle and remove the QR and screw the axle into the mech mounting hole (both are M10 X 1) and then with a wheel in the frame you can align it fairly accurately. if it is way off an adjustable spanner may help to get it close first.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • keef66
    keef66 Posts: 13,123
    Bloody great adjustable spanner is all I've ever used to straighten the kids' bikes mech hangers, but I wouldn't hold out much hope of preserving the paint.
  • markos1963
    markos1963 Posts: 3,724
    I had this on my old steely, don't blame me by the way if it doesn't work out. I got an old rag and wrapped it around the hanger and then used my good old molegrips to GENTLY and GRADUALLY pull it back into shape. The only paint I lost was around the dropout and that was covered up by the QR
  • dbb
    dbb Posts: 323
    the wheel is a great idea!
    i have also just used an allen key! keep the RD attached to the frame and insert the allen key into the RD as if you were going to tighten/loosen the rd. but just use the allen key as a lever in the allen head.

    i have also successfully used a big shifting spanner.

    if it is a top frame and you really want it to be perfect, then a good lbs will have a special tool. (many years ago, i worked in a shop). the tool is effectively a rotating lever that screws into the hanger. the lever extends to the length of your wheel rim and as it rotates you can measure the gap between the tool and the rim. the lever can then be used to bend the hanger back into position from any angle.

    hope this helps.