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Fixing Chainline Offset - Hub to Sprocket Offset

Please I need some help.

I'm trying to fix the chainline offset as I'm designing a frame using Shimano Alfine 11 DI2 (SG-S705) and the Gates Carbon Drive.

I'm having a 12mm issue on the chain line.

So far I've got able to draw a assymetric chainstay to go around the belt avoiding a chainstay coupler and enabling larger tire clearance.



How do I adjust the offset from sprocket to hub ?


I'm trying to build clearance for 35mm tires and a bit of mud. Will use an Eccentric BB. Feel free to suggest as this is my first time designing a frame.


Full techdocs:

Shimano Specs

Gates Specs


Fixing hub to sprocket offset

It looks like you've correctly set up your hub flange dimensions to reflect the published specs for the Shimano Alfine 11 Di2. The Gates documentation suggests a "Belt line" dimension of 39.8mm (Dimension A in the diagram below).

Although you cannot directly enter this dimension in BikeCAD, you can show this dimension in the Dimensions dialog box by selecting Stays (auxiliary view) >> General >> Rear chainline. The position of the rear cog can be located in BikeCAD with dimension Z in the "Sprockets" section of the Drivetrain dialog box. Dimension Z locates the rear cog with respect to the inside face of the drive side dropout. Therefore, Z = O.L.D./2 - Rear chainline. Subbing the appropriate numbers in, we get Z = 135/2 - 39.8, or Z = 27.7. I've changed this dimension in your model to get the result below:


Great, thank you very much,

Great, thank you very much, now I can continue playing with the exquisite drive side chainstay and see if it's still necessary.

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