Does anyone know the best place to buy a rear derailleur hanger cheaply. Mine is now at a 30 angle to my frame. It bent when I broke a chain. Also wanted to know If and how I can check whether I bent the chainstay or the derailleur in the process.
Any help would be Appreciated.
p.s. Its on my road frame
usually any place that carries the brand of bike the hanger belongs to is a good place to look
do you have a specialized frame?
You can look up your bike and try and find the hanger on http://derailleurhanger.com/. If you’re lucky a shop that sells your brand might have the hanger, but there are just so many versions that it’s kinda rare, but most shops should be able to order them. There’s a tool for checking/aligning the frame. I don’t remember much about it, but i think we had one at la cordee. There’s another tool that adjusts the hanger once it’s on. As to the derailler, i’d assume that if it looks fine its fine. So long as nothing’s loose or obviously bent.
the tool that you need is this: http://www.parktool.com/products/detail.asp?cat=48&item=DAG-2 . I would let you borrow it, but it’s at home in the states. Most bike shops should have it. All it does is check the alignment of your hanger, but then all shops do is push/pull it whichever way is needed to make it aligned. So, once you have your new hanger installed, you’ll want them to check the alignment to insure that the dropout is not slightly bent. Once you have those two things aligned you can check if your derailleur is aligned.
The way the mavic support crew checks if the derailleur is aligned is to first make sure the gears are shifting well, then walk your bike backwards. If your chain stays in place and doesn’t shift gears or sound bad, then your derailleur is aligned. If your chain doesn’t, then your derailleur isn’t aligned and all you need to do is bend the cage a bit until it stops making noise. After riding it for a while, and your chain occasionally drops off your front chain rings, it means your derailleur and/or hanger are not aligned correctly.
In theory you’d want to check your dropout alignment as well in case part of the rear triangle bent (very unlikely from a chain breaking accident unless it say, made you crash on your derailleur).
Park has a neat tool for that as well (FFG-2). There is also the unfortunately named FAG-2 for overall frame alignment.
The tools are nice, but really you can do hangar and cage alignment by feel by watching the shifting like Stephen said.