Originally Posted by 16v4nrbrgr
It's worthwhile installing an idler sprocket in place of the plastic roller, it will run smoother and keep a constant tension because it interfaces with the rollers on the chain versus the side plates which are typically fiddle shaped.
As long as the sprocket is not a plastic one meant for use on a derailer. Also chain alignment becomes more critical. But chain / sprocket alignment should be right on the money anyway.
Not sure if a sprocket would be as quiet and smooth as a urethane wheel with bearings. They're noiseless.