# What's the standard for a rear derailleur hanger?



## bcmanucd (Oct 18, 2005)

Hi Folks,
I'm designing a set of horizontal rear dropouts with derailleur hanger a la Cervelo. Does anyone know what the standard specs are for the derailleur hanger placement?
I've measured a few road bikes and all of them seem to position the derailleur bolt hole 25 mm from the rear axle (c-c), but the angle between the chainstay and the line through those points seems inconsistent. I'm just wondering if Shimano or Campy have published guidelines, or if one of you has fiddled with this dimension and drawn any conclusions.
Of course the horizontal dropouts make it less important, but it'd be nice to optimize it for one position at least.


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## pvd (Jan 4, 2006)

Why not just buy some?

Of course Shimano has documentation available.


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## dbohemian (Mar 25, 2007)

I have some extra,










$35.00 shipped. 17-4ph stainless plate.

Dave Bohm
Bohemian Bicycles


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## nateknutson (Mar 15, 2008)

I've got this thing. I have no idea whether Shimano has put anything else out along these lines.


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## bcmanucd (Oct 18, 2005)

Thanks Nate, that's exactly what I need.


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