A RD was recently lightly smashed in. I straightened the derailleur hanger "by hand" and now it is "good enough" with some chain rub on the cogs. I set out to readjust the rear gears but am facing the following problem: no matter what I do, the chain is never prevented from dropping between the cogs and spokes at low gear ratio.
I took a closer look and while the high limit screw rests against a wide platform on the body of the RD, the low limit screw seems to resist against the thin wall of the parallelogram!
My hypothesis is that the parallelogram is bent and "too open", so a suitable repair would be to bend it inward a little so that the screw makes contact. But that sounds too sketchy - why wouldn't there be a platform for the screw to resist against? Am I in error?