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Crashed into a fallen tree at speed on my bike. I disassembled the front end to inspect for damage and noticed I could wiggle the bottom headset cup back and forth slightly. On further inspection, the bottom of the headtube is slightly deformed as can be seen in the below pictures:

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There are no cracks or other damage visible, but the bottom cup no longer fits firmly in the frame.

Does anyone have experience fixing something like this on an aluminum frame (not too expensively) or is the frame/bike ruined? I know aluminum loses its strength as it's bent.

Searching online I was able to find references to epoxying the bottom cup in place and using strips of aluminum to pad the gap, but that doesn't sound like a particularly safe fix.

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If I was that desperate to save the frame, then the epoxy method sounds quite reasonable.

The only difference I'd make would be to use some carbon fibre in place of the aluminum strips. It's pretty cheap to get a short roll from Aliexpress

Put the bearing in and out a couple of times until it's a snug fit. Pull it out, epoxy the carbon, pop it back into place, clean excess resin off

If you can do it with the bearing wrapped in glad wrap, you may not even have to make it your last ever bearing change as you should be able to remove it once the epoxy is set

Whilst the aluminium will have lost some strength, it's not going to fail catastrophically in that position as it's really well braced

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  • That's a good idea. Thanks! By carbon fiber rolls do you mean the vinyl wrap type that is used to wrap cars? That's the vast majority of what shows up when I search aliexpress, but I'm not sure if that's actual carbon fiber.
    – John
    Commented Apr 19, 2020 at 20:22
  • Try carbon fiber cloth as your search aliexpress.com/item/32905572988.html
    – Noshy
    Commented Apr 20, 2020 at 4:02
  • It must be actual carbon fiber.
    – Noshy
    Commented Apr 20, 2020 at 4:05
  • If you have an old fork that you can use to ensure that it's aligned correctly whilst it dries, it's probably going to give you a better result.
    – Noshy
    Commented Apr 20, 2020 at 4:07
  • Thanks! Searching for "carbon fiber cloth" turned up much better results. I ordered some.
    – John
    Commented Apr 22, 2020 at 2:06
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The epoxy method should work, but there are better things than epoxy. Consider something like loctite 680. It's a sleeve-retaining compound specifically for metal with loose or slip fits.

I would suggest assembling the headset with gentle pressure and leaving it assembled while the glue dries. It will help keep things in alignment. Just make sure no glue leaks out where it shouldn't be, though.

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  • Thanks for the suggestion! I will pick up some loctite 680 and use it instead of epoxy.
    – John
    Commented Apr 22, 2020 at 2:07

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