BMC GF02 chain stay crack?

sil4 Posts: 5
Any thoughts on this would be appreciated

I noticed today what looks like a longitudinal crack in the l/h chain stay of my 2015 BMC GF02 disc, aluminium frame: surface is slightly ridged and self-evidently crack-like. 1000s of road miles covered but never absued/crashed. Just wondering whether it's not as bad as it looks or a horrible failure just waiting to happen?

Don't want to scrap it but don't wish to end up in A&E either.


  • ugo.santalucia
    ugo.santalucia Posts: 28,237
    A crack or a scratch, hard to say from here. Why is the tyre running so close
    left the forum March 2023
  • Charlie_Croker
    Charlie_Croker Posts: 1,698
    Not sure from pic I'd try to get a NDT done if you have access to a facility near you (google or yellow pages)
    I'm guessing any warranty has gone by now, shame – any insurance for this sort of thing?
  • redvision
    redvision Posts: 2,958
    To me that looks like a scratch but hard to tell from that picture.

    As Ugo says, the tyre does appear to be very close.
  • edward.s
    edward.s Posts: 219
    If you are unsure, about a tenner buys you a crack detection spray kit. get one with the 3 different sprays.

    We used to use the crack detection kits looking for cracks in welded aluminium air enclosures so I imagine they'll work on a frame. Might need to be careful on a painted surface though, I've only used them on bare metal so perhaps check that with the supplier first.

  • sil4
    sil4 Posts: 5
    That's for the responses. The picture is deceptive - the wheel/tyre are the standard fitment, straight and true with plenty of clearance and no potential for rubbing. No obvious way it would have been scratched and it's only recently appeared: the surface is ridged so feels more like a crack than scratch: but impossible to tell. Frame well out of warranty sadly - no flaws elsewhere and it's otherwise fine to ride but will explore detection options...