Welcome to the new and improved Proflex / K2 Tech Forum!
Maybe someone here can help. I've got a medium K2/Proflex 4000 (unknown year) and the Noleen rear shock is pretty much dead. Will the Vanilla RC fit and work?
Kindof. It will work great if you switch to a 24" rear wheel.
A 24" rear wheel will create the same problem as running a 7.875" shock, a slack steering angle. Does the 8.5" shock hit the rear tire?