Pitlock secures the front wheel solid axle of the shimano hub dynamo by using a m9 x 1 thread a closure for one side 1 closure m9 x 1 1 pit key for solid axles 1 code cardthe protruding thread is supposed to stick out of the dropout for approximately 14mm the locking ring requires a space supporting surface of 15 mm in the radius or rather 30 mm in the diameter around the thread so that the pitlock lock can be installed safely