Recently we’ve designed this 2 speed ball shifter gearbox for using in drivetrains, running 3 CIMs on each side. The top speeds are 1880RPM on high gear and 710RPM on low gear, amounting to a spread of about 2.65x. We decided to design this gearbox in order to customize it more to our needs and also save money, since each gearbox is about $100 cheaper than a COTS equivalent. We are making the CAD files avaliable to anyone interested in having a look here: https://drive.google.com/open?id=0B0AbUufPJzpwZFBVbHUxS2ktR3M. What are your experiences with 2 speed custom gearboxes and 6 CIM drives?