Derailleur hanger dimensions
07-08-21, 02:37 AM
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Derailleur hanger dimensions
New to bikes and framebuilding , I'm building my first frame , a lockdown project that's nearly done. I am making rear dropouts and want to buy a derailleur hanger and fit it to use a Sram X9 rear mech , but when I look at the Sram manual it specifies 28mm - 30mm as a distance from centre of the derailleur fixing hole to axle centre , and other derailleur manufacturers specify their own distances for this dimension , yet only one of the many many hangers I have looked at online offers this measurement as part of their description (and that was 34mm , outside Sram's limits). I don't quite understand , is it not as important as Sram say it is? If it is , how do you find one that fits or do you have to measure every time you put the wheel in?
07-08-21, 03:53 AM
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That distance is not as important as SRAM makes it sound. There are plenty of SRAM derailleurs mounted to Shimano spec. derailleur hangers that work just fine. I'm not sure what you mean by "do you have to measure every time you put the wheel in?". The length of the hanger doesn't change and if you are making standard QR or thru axle dropouts, the axle sits in a fixed location.
Paragon Machine works makes SRAM specific versions of their derailleur hangers. I don't know your level of machining experience or how you plan to make your dropouts, but most derailleur hangers are designed to fit into a machined interface with the dropout. Making one fit properly will require a CNC machine and some CAD design experience. That is why most of use purchase dropouts and the matching hanger from a supplier like Paragon.
Paragon Machine works makes SRAM specific versions of their derailleur hangers. I don't know your level of machining experience or how you plan to make your dropouts, but most derailleur hangers are designed to fit into a machined interface with the dropout. Making one fit properly will require a CNC machine and some CAD design experience. That is why most of use purchase dropouts and the matching hanger from a supplier like Paragon.
07-08-21, 05:30 AM
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That distance is not as important as SRAM makes it sound. There are plenty of SRAM derailleurs mounted to Shimano spec. derailleur hangers that work just fine. I'm not sure what you mean by "do you have to measure every time you put the wheel in?". The length of the hanger doesn't change and if you are making standard QR or thru axle dropouts, the axle sits in a fixed location.
Paragon Machine works makes SRAM specific versions of their derailleur hangers. I don't know your level of machining experience or how you plan to make your dropouts, but most derailleur hangers are designed to fit into a machined interface with the dropout. Making one fit properly will require a CNC machine and some CAD design experience. That is why most of use purchase dropouts and the matching hanger from a supplier like Paragon.
Paragon Machine works makes SRAM specific versions of their derailleur hangers. I don't know your level of machining experience or how you plan to make your dropouts, but most derailleur hangers are designed to fit into a machined interface with the dropout. Making one fit properly will require a CNC machine and some CAD design experience. That is why most of use purchase dropouts and the matching hanger from a supplier like Paragon.
