Blu ray drive only reads discs that spin freely when it is open

[diapolical]

There are a lot of DVDs that my laptops BluRay drive won't read and I can predict which ones.
If I open the drive and seat the dvd then spin it manually with my finger, if it spins freely it will play, but if it doesn't "freewheel" then it won't play when I close the drive (the computer doesn't recognise a disc as loaded in the latter case). Some discs simply will, others just won't!

Why do some discs spin freely and some others don't?

Obviously this is a physical problem but does it mean there is something wrong with the BluRay drive?

What makes some DVDs physically different to others?!

It is frustrating because there aren't a lot of DVDs I can play.

At least the drive is consistent, if a disc spins freely when the drive is open then it WILL play. And once a disc plays, it plays every time!

I cant find anything on the internet about the correlation between freely spinning discs and playable ones, or why some discs spin freely and others don't.
Any ideas here?

(I know this is not a software issue so I am not willing to explore that area)

 

[diapolical]

I sorted this out.

It was a mechanical fault, the central mount that goes into the center of the disk was too high at the back causing the disk to spin unevenly.
I loosened the screws underneath it then put 2 small pieces of rubber between the plate holding the mount and the plate it was attached to. I tightened the screws but not as much as originally. I put a tiny amount of superglue on the screws to stop them loosening.
This leveled off the central mount/wheel.

It works perfectly now. No fault at all.

How do I mark this as solve if nobody comments?