Rear derailleur problem

shknnotstrd

Complete noob here. Just purchased a used 2015 Cannondale Synapse Carbon 5 with a 105 group set. After assembly and a test ride, I noticed that the chain seemed to ever so slightly skip from time to time. Google told me my hanger may be bent(probably from shipping), so I went tinkering. After tangling the hell out of my chain and removing the derailleur I got it back together. Now the cage plate and pulleys seem to be out of position. The rear wheel drives with pedaling, but is obviously having some issues. When I pull the cage plate down towards the floor, it pedals smoothly. What the heck did I do?

wongataa

Go to the Shimano website. Find the technical docs section. Find the datasheets for your rear derailleur. Follow the setup instructions from scratch - start by taking the cable off. This will teach you how to setup and how to adjust the rear derailleur.

sungod

sounds like you may have misrouted the chain, if you get it the wrong side of a pin/tab in the cage it'll 'work' but it won't be good

as above look at the instructions

the original issue may have been the rear hanger, but more likely is that the indexing needed adjusting (using the barrel adjuster) - with a new build it takes a few rides for cable outer/ferrules to seat fully, until then you must be prepared to do a bit of tweaking

if the hanger is bent, you need an alignment tool to adjust it correctly (there are other improvised methods, but simply eyeballing it is not precise enough) or get the lbs to do it

shknnotstrd

Thanks for the replies. I ended up taking the bike to a local shop. I figured I may end up doing more damage than good