My LBS just replaced my old BB to a new one and I got back my old-worn out BB. I have never fixed a bottom bracket before so I am new at this. How come the removable ring on the non-drive side just rotates and doesn't get detached from the BB body? According to Park Tool website, removable ring is either on the driver or non-drive side. If the removable ring doesn't detach, how are you supposed to install it onto your BB shell?