I'm trying to replace my rear derailleur. I've never swapped one before so this is all new to me.
I'm stuck at the stage on how to mount my new RD onto the hanger. The interfaces are slightly different.
I tried to mount the new RD, but I realized it appears to use different mounting interface (where it connects to the hanger). After 10 minutes of trying various angles to mount it, it seemed like none of them was looking correct. There seems to be a cutout on the back of the mounting flange, so I tried to align it to the hanger edges, but it overlaps each time and doesn't look right.
So I figured I'd post here for help. I checked my bike mechanic book, searched BF, googled but I'm still not sure how to proceed.
Thanks for any tips
First pic shows my old RD
2nd pic is comparison of old (top) and new (bottom)
3rd pic is rear mounting "flange" of new derailleur
4th pic is my attempt to mount the new RD, but it's not aligning smoothly. The little metal flange doesn't seem to line up with the contours of the hanger
fwiw, here's a link to the new RD I'm trying to install