ISCG-05 tabs (adding)

To add ISCG-05 chainguide tabs in BikeCAD version 23.2, open the Tubing dialog box because this is where the bottom bracket shell is defined. Right next to those controls, is the ISCG-05 menu with a choice of increasingly sturdy styles of tabs. Since the ISCG-05 standard requires a bolt circle of 73mm diameter with 3 holes spaced 100° apart and the bottom rear hole being 50° below a line drawn from the rear axle to the center of the BB, all of this is hard coded into the program. We can see that as the BB is dropped the ISCG tabs will rotate to maintain the required 50° angle. The only thing we need to do is ensure that we've entered an appreciate offset from the face of the BB shell which is dimension Z as well as an appropriate thickness which is dimension T.

If we export our model to FreeCAD, you will see that the tabs appear in our 3D model as well.