How can you tell if you derailure or the hanger is bent on the bike and which one it is.
I believe something is messed up about my rear drive train. No matter what I do or try to do when ever I am in the middle chain ring it skips and it all over the place. I manage to get a look at it to day and I see it jumping in the back first.
Right now when the wheel spins and the casset does not move it will wobble back and forth a little and at a certian point it sounds like something is rubbing so I am not sure if that is the cause of the jumping problem.
The other is it does not look like the derailure will line up straight with the cogs but I am not a 100% sure could just be the way the fame is making it look like the top jocky wheel is not straight with the cogs.
Would the LBS be able to really tell me what it is and would this stuff be causing my chain to skip like crazy. I really want to get it fix because it is sucking all the enjoyment out of riding for me and it is just not fun to do it when the chain skips under any type of load under the main chain ring. It pushing me to want to saw screw this and just not ride. It sucks having the chain drop and skip every pedal stroke or 2 and some time multiple times in a single pedal stroke. I want to know what the possible causes are and solutions.
chain slack could be one reason. and regarding the cog wobbling check the star lock nut, make sure that is tight. if it is, remove the sprocket and check your free wheel cassette, that could be broken or just need tightening.
Look at the derailleur when you are riding: if its two jockey wheels are not directly under the gear that the chain is on, then something is bent. How do you tell if its the derailleur or the hanger? In my experience it has always been the hanger.
But Sheldon Brown says that more than 90% of shifting problems are caused by the cables.
Originally Posted by Wombat
I am going to take it the lbs should tell me if anything is bent and exactly what part is bent. Along with do it very quickly. From there I will decide on how I want to go about fixing it.
It all depends on what it is will determine how I will go about replacing parts. (for example if the derailure is in need of replacing I will be replacing most of my rear drive train as it will be when I do a massive upgrade and make into a sram 9 speed.
My way of dealing with bent hanger is this: I wait(if the gears still shift well enough) until I need something from my LBS. Then ask to straighten the hanger - the work takes just couple of mins, if not less, so usually I am not even charged for it. I can straighten the hanger myself, but can't match precision of the device the LBS has.
Normally, if the derailleur is bent, the hanger is as well. .