The first time I took my trike to a cycle shop for gear adjustment, they insisted it was the wrong kind of derailleur because there was no way to get it to work smoothly. After my husband and I beating our heads on it for a while, I took a bunch of pictures to send to the ICE people. In less than half an hour, they wrote back that the shifter cable had been threaded around the screw in the wrong direction. I'm sure you've looked into that, but I was stunned that such a little thing could cause such a big headache.