The park tool der. Hanger straightener works really, really well... Down to a mm ! Donno what I think about taking the hangar off and checking it on a flat surface, it's a start but then what's next ? Adjusting it with a hammer ?have either shop show you how it works, both checking and adjusting... There is no real need to repl. the hanger, unless it's broken. Same goes for the rear der. If you want to repl. Various components for cosmetic reasons you are welcome to do so, just don't throw parts at it to fix a problem that may or may not exist. Which will get expensive, and if you dont know how well a 105 rear der. Works, than you are wasting your time and money. ( the answer is, as good as the shifter pod thats telling it what to do, and the cable connecting them to each other. Thats why everyone is asking about the cable and housing conditio. Rear Der. Are all the same in function, some are made from lighter material, but none have speeds assigned to them, that's what limit screws are for. ) This is where finding a good shop that you can trust comes into play ... Get a second opinion, if you must ... But be aware, bikes are easy to recognize Esp. If they have a certain issue, attached to them ... when it comes back for another issue, and the old issue was solved, Esp. With new parts, get ready to be treated differently.
Last edited by martinus; 05-02-13 at 06:59 AM.