I just got another old bike. It's got a threaded headset lock nut. Talking 90's UK Raleigh. The lock nut measures exactly 30mm. With wrenches does this mean I need 30mm wrench or a 32mm wrench? I guess I'm asking a basic question, the size stamped on a wrench is the size of nut it expects to turn, right? So a 30mm should be the one? I know that they typically come in a 30/32 set (double ended). Just wondered.