chikatetsu

Hi everyone,

I have a 2008 Cannondale System Six 3 which, until recently, has been running on stock components. I recently changed the rear cassette from the 12-25 to a more forgiving 28 (both Ultegra parts) but it seems like cassette is the wrong size. For example, when I'm in the largest rear cog, it looks as if the top jockey wheel is too close to the cog teeth and the chain can't run through smoothly enough. Is a 28 teeth ring just too large or can I just adjust the derailleur arm (using the b-screw IIRC) to move everything down to create more clearance? I hope that this makes sense and that someone can help。