Need a new rear derailleur and hanger how do I know what to get?
It's a 2014 specialized crosstrail it has 8 speeds in the back and Shimano altus.
If I search out altus on Amazon I see a lot that have another word too like Revere altus or mehgna altus and they say they have their own factory, are these ripoffs? Like this:https://a.co/d/8gKrQq4
Are there different types of Shimano altus rds? Or if I find a genuine one are they all the same?
And is a hanger specific to a bike or are those generic? Thank you all for any help really want to get back to riding again.