Shimano 105 Derailleur Setup - What Have I Done Wrong

[BeirutTaxi]

Dear all,

Currently rebuilding my Bianchi road bike, however I've set up the rear derailleur wrong and I don't quite know how. I had the issue before months back on another bike and I can't remember how I fixed it!

See the pic - It's at the wrong angle.

Chain was measured and is the correct length.




Many thanks,



Matt

[anonymous-user]

Picture is a bit too small to see anything of detail - what's wrong with it?

[numtumfutunch]

^^^^^ agree - need a better pic

[Justin S]

If you've got it on the large chainring on that sprocket, the chain is too long. Agree on a better photo.

[richardxjr]

Is the cage fouling the largest sprocket? If so wind the B-screw in until it doesn't


And sort the washing out

[Catchme]

Make sure the tab on the derailleur bolt sits behind the gear hanger, otherwise the cable will pull the derailleur forwards when under tension.

[BeirutTaxi]

[skyrocket13]

Undo the cable, the rear mech should not be pulling back in that position. Should be almost vertical on the hanger.

[upsidedownmark]

What catchme said. When you bolted the deraileur into the hanger, you've not got the tab engaged so the spring is doing it's job - it's a bit hard to explain, but if you take it off you should see what we mean - there's a spring around the bolt that pulls the cage forwards - that engages against the hanger with a little tab. Until you get the hang of it, it's a bit fiddly to get on correctly.