42 tooth cog
Charles Ramsey 1s
It works. In order to get the 42 tooth cog to work I had to widen the spacer from 2.5mm to 3mm. The derailleur also has a 15 tooth jockey pulley. This might not work with a 13 tooth jockey pulley and I don't have one to try. I will be going back to 39 teeth cogs. The new style megarange derailleurs look like they will work with a 40 tooth cog but probably not with a 15 tooth jockey pulley. A 39 tooth cog will also let me use a 28 for the second largest cog. All this came out of recycle bins I use what I find. The old style megarange derailleur also works in all gears giving it a 52 teeth or greater chain take up.