Note: These haven't been tested yet!

A front derailleur shim that adapts a 34.9 clamp to a 28.6 seat tube, while also changing the angle of the derailleur to the horizontal. This is useful to move the cage closer to the rings, which can help prevent rubbing when using a derailleur designed for larger chainrings with smaller ones. It could also work in the other direction, making a regular front derailleur fit extra large chainrings (like used on folding bikes and minivelos).

There are two designs:

• A two-piece design that is centered on the the tube, in two angles: 7 and 15 degrees. You will need to print two copies.
• A one piece design that is eccentric (like my eccentric shim model) in 5 and 10 degrees. Because of the angle offset you can't rotate the shim to adjust the offset, but it does shift the cage forwards or backwards a couple millimeters and might be useful to gain some room if your front derailleur clamp band is close to your water bottle cage.