as to bear against the fitting 806 and be aligned with the re centering spindle 802 this spindle 802 actuated by another cylinder 801 is introduced into the valve hole so that the axial insertion spindle 813 and centering spindle 802 are brought into mutual alignment with a common axis coincident with the centre of the valve hole this axis forming an angle d with the plane of symmetry of the rim having thus centered the valve hole of the rim the locking means 811 associated with ball joint 810 hold the bracket 809 against movement so that the centering rod 802 can be retracted from the valve hole the valve insertion cylinder 805 duly provided with a valve sprayed with soapy water is then actuated to insert the valve into the rim valve hole when the operation is completed means not shown may be used for checking the proper positioning of the valve in the rim and the bearing rollers 302 are retracted to free the rim finally the rim with the valve inserted therein is conveyed from the operative position b to the discharge position c and at the same time another valveless rim is moved from position a to position b during the rim transfer the bracket 809 recedes and resumes its position within the centering means 812 cylinder 805 on the other hand resumes its vertical position by pivoting about its pivot pin 808 and is ready for starting another cycle due to the provision of two valve selection bowls 701 702 it is possible to fit one of two different valve types the selection being made externally of the machine after selecting the proper valve type the cycle will start again.