Originally Posted by
swc7916
Sorry, my suggestion was exceedingly dumb; eccentrics are always on the front, not the back. My new bike has two eccentrics because I don't have derailleurs and I guess I was picturing that configuration.
The eccentric is used to adjust the slack in the timing chain. You don't need one in the rear because the derailleur takes up the slack.
Been there done that, after you get to know me you'll find I'm full of dumb suggestions! Don't ever let it slow you down!