# 2017 S5 derailleur hanger movement



## choogenboom (Feb 2, 2021)

anyone out there experience the following:

When closing the QR skewer the dropout and the attached derailleur hanger flex inward, ie bringing the derailleur cage in closer to the centerline of the frame.

Was a little disconcerting to see it, and means the frame is under constant stress during normal operation.


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## duriel (Oct 10, 2013)

Your frame may be bent or you may have rear triangles that are bent wider. Adj the RD with the wheel tight.
When your riding straight, run through 10' section of water on the road and then observe the tracks of your tires while riding straight. Are they one line or two?


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## choogenboom (Feb 2, 2021)

I could be wrong but I don't think carbon fiber "bends" and then stays bent in that new position? If you have better information on how carbon fiber frames can be permanently bent I would of course like to learn.

To add some detail, the dropout faces are, I believe, machined after the frame has been molded. They are machined to tight tolerances to ensure that the wheel sits in the centerline of the frame and that the two faces of the dropouts are coplanar and parallel to the centerline of the frame. The issue with my frame is one of those dropout faces, specifically the derailleur side, is not coplanar with the centerline of the frame. When the skewer is closed and the dropout face is squeezed in to the mating face of the axle the face of the dropout is forced to coplanarity with the axle face and it is that action that then forces the entire dropout, including the derailleur hanger and the attached derailleur, into a new position/angle that is not "natural" ie, the new position puts the frame, in the area of the dropout, under a permanent stress load. I eyeballed the derailleur cage and it looks "pretty good" so the distortion caused the lack of coplanarity is not a showstopper to the drivetrain's performance per se but the idea of riding the frame with a permanent "bound up force", ie a stress load, is disturbing.

Which brings me back to my question. Has anyone had a similar experience? Solution is?


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## duriel (Oct 10, 2013)

So, new information? CF, who knew?
... and dropouts are machined after installation in the frame? Really?

Solution: File a warrenty claim. Oh wait, this is the Cervelo subforum, good luck with your claim.


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