People have been asking us for wheel extensions for the Catrikes for a long time. The Catrike dropout released for the 2005 models is nice and beefy and gives us a real nice mounting surface to work with.
Our goal is to come up with an extension that will work with all 20-inch rear Catrike models. The extension should preserve the original steering geometry. The extension should allow the use of a fender, rack, and even Big Apple Tires. The Extension should not add any "flexiness" to the trike beyond what is inherent in a larger rear wheel.

This is the renders of the final version before they were sent to the machine shop. As you can see we were able to meet our goal of sturdiness by pocketing around the Catrike dropout.
For the final version I included the rear brake mount on the left side.

This project has now been released for production. You can view purchasing details here.