There always comes a time when one of these little buggers falls off, and then begins the annoying process of unwinding grip tape on a road bike. With a handy 3D printer and Autodesk Inventor, this problem is an easy fix. If you are to do this at TechShop like I did, it's even easier.
The class needed for this project is the 3D Printing SBU and then of course you need a membership. If you wish, TechShop also has Autodesk Classes for members to get you started in the software!

Step 1: Measure the Handlebars

Using a digital caliper, I measured the inside diameter of the circle to use for reference in the autodesk sketch. What I got was .77in for the interior diameter. This is really the main bit that is needed for design. I also measured the thickness of the metal itself to give a good reference of the total size since I didn't have existing caps to work with.

Step 2: Designing the Basic Sketch!

Follow the pictures!

Step 3: 3D Sketch!

Step 4: Extruding!

Step 5: Print It Out!

With all the design work done, take it to the printer.

For this project the Up! Printer and the Replicator were out of operation, so these were printed on the thing-o-matic. Don't worry about the settings in Replicator G, those are incorrect. The fill should be 100% to make sure it's a solid piece so that it doesn't snap during installation. In addiditon, the layer height I believe I got working was around .5, rather than .2 pictured.