When the rear swing arm moves up and down during normal use I'm thinking the angle of the rear shock(s) will have to change. And to enable this change, I'm thinking the shock must also have to rotate very slightly around it's mounting bolts. For single shocks with triangles at the bottom etc there is usually a needle roller bearing of some sort to allow this. But how does the movement occur at the top of the shock or in the case of twin shocks at both ends when they are bolted direct to the frame/swing arm.
You're generally bolting the shock ends to the inner part of rubber bushes, so the minor rotation is accommodated within that rubber.
