Is there a specific chain length or secret process to setting up an Duopar eco? I have higher quality derailleurs that I am using but I have the Duopar in the shed and I would like to play around with it. I had it on my Super Course briefly while it was in the stand. It would not even handle the 33 on the cassette cog. The pulley rode against the cog because the second parallelogram was not dropping the pulley enough. I could push the parallelogram down, but it would pull back up as soon as I pedaled. I wondered if the chain needed to be shorter but I didn't want to break the chain since I was planning to put the Suntour one back on.

For the record, I had the correct washer to hold it in the right position on the dropout and I used the wedge screw to hold the derailleur in place while allowing it to move on the dropout.