I’m a bit confused as to where the movement in the rear shock mounts happens. In most setups linkage plates are mounted to the shock eyelets via cylindrical tubes with a bolt through them. The tubes are normally well stuck into the eyelet when I have removed shocks. When you do the bolt up it clamps everything fairly tightly, and there isn’t any movement without a bit of force.

What I don’t understand is why there is no purpose made rotating part in the setup, are you just relying on a bit of movement (probably only a degree or so)between the bolts and the plates? Or is the eyelet supposed to allow the shock to rotate around the mounting cylinders?

This post probably doesn’t make much sense does it…

In most setups linkage plates are mounted to the shock eyelets via cylindrical tubes with a bolt through them

Even my retro throwback turn of the century Cannondale has bearings in the linkage plates. Would’ve thought other bikes are the same?

there’s a bushing in the eyelet that allows the shock to move about the cylindrical tube.

DU bushing in shock eyelets in general, although there are other alternatives.

ok, think my bushings have all been worn out then as they’ve always been very hard to move!

Or is the eyelet supposed to allow the shock to rotate around the mounting cylinders?

This is what happens, and is meant to happen.

ok, think my bushings have all been worn out then as they’ve always been very hard to move!

No, they get slacker as they wear. You are underestimating the forces applied at the end of the shock (large fractions of a ton or more), the friction you are feeling is trivial by comparison and it all moves fairly freely under load.

What I don’t understand is why there is no purpose made rotating part in the setup,

There is, the bushing in the shock is that part. It’s a very light, small and strong solution for that particular loading, anything that moved freely like a ball race would have to be huge and heavy to take the loading.