an exemplary embodiment of a tire changing apparatus made according to the invention is illustrated in fig1 and is seen to include a base , generally designated 10 including a bottom or floor plate 12 and an upstanding post 14 . at the upper end of the post 14 , the same mounts a tire receiving table 16 . the table 16 includes an elongated opening 18 in the upper side thereof through which a prong 20 extends . the prong 20 may be disposed in a lug receiving hole in a wheel disposed on the table to preclude the wheel from rotating during a tire changing operation . the prong 20 is biased upwardly by a spring 22 in a conventional fashion . extending upwardly from the center of the wheel receiving table 16 is a threaded post 23 upon which the wheel may be impaled . suitable threaded clamping means ( not shown ) cooperate with the threads on the post 23 for firmly holding the tire in place on the table . generally , a bead breaking tool such as the bead breaking tool generally designated 24 will be utilized in connection with the tire changing apparatus . the same includes a handle 26 . at the end 28 of the tool opposite from the handle 26 , the same includes a pivot pin 30 . a link 32 is pivoted to the end 28 by the pivot pin 30 and at its end remote from the pivot pin 30 mounts a sleeve 34 which is dimensioned so as to be receivable upon the post 18 . intermediate the end 28 and the handle 26 , a bead breaking shoe 36 is pivotally mounted as at 38 to the tool 24 . as is well known , when the upper bead is to be broken , the collar 34 is disposed about the post 23 with the bead breaking shoe 36 depending from the handle 26 . the bead breaking shoe 36 is located adjacent to the bead on a tire and upon the application of sufficient downward pressure to the handle 26 , the upper bead will be broken . when the lower bead is to be broken , the link 32 and sleeve 34 are unused and the tool is oriented generally in the position illustrated in fig1 with the bead breaker shoe 36 extending upwardly . the same is then located adjacent the bead with the end 28 secured , by some suitable means , to the tire changing apparatus . upon the application of sufficient upward pressure on the handle 26 , the lower bead will be broken . however , in some instances , for any of a variety of reasons , there is insufficient upward movement , or &# 34 ; throw &# 34 ; of the bead breaker shoe 36 to break the bead , particularly on relatively small diameter rims , or with extremely wide tires . in such a case , it is necessary to elevate the point of attachment of the tool 26 to the apparatus . the present invention contemplates unique , easily useable means for the purpose . in particular , a pair of parallel spaced arms 40 are pivoted as at 42 to the base 10 , and specifically , the post 14 , below the table 16 . as best seen in fig2 a pawl 44 extends between the arms 40 and is secured thereto by any suitable means as , for example , by welding . the ends of the arms 40 opposite from the pivot pin 42 have bead breaker tool receiving means formed therein in the form of a notch 46 . the notches 46 in the arms 40 open upwardly and diagonally toward the end of the arms 40 opposite the pivot pin 42 and as best seen in fig2 include a partial hook formation 48 at their upper ends . notches 46 are adapted to pivotally receive the pivot pin 30 of the tool 24 . the upper end of the post 14 , just below the table 16 , includes a lateral extension 50 mounting a pivot pin 52 . the upper end of a ratchet 54 is pivoted to the base by the pivot pin 52 so as to depend therefrom . as seen in fig2 the ratchet 54 includes plural , upwardly opening teeth 56 . below the teeth 56 is a lateral extension 58 and a depending handle 60 . the teeth 56 and the extension 58 cooperate with the pawl 44 and the undersides of the arms 40 , respectively , to position the arms 40 at some desired angular relation about the pivot pin 42 and thereby control the height of the tool receiving notches 46 and thus the maximum uppermost position of the bead breaker shoe 36 . in general , it is desired that the teeth 56 be located on the side of the ratchet 54 nearest to the post 14 and that the pivot pin 52 be located nearer to the post 14 than the nearest contemplated position of the nose 58 of the pawl 44 to the post 14 . when such a relation is employed , gravity will always tend to cause the ratchet to pivot into engagement with the pawl eliminating any need for additional parts , such as biasing springs , or additional effort on the part of the operator in terms of manually engaging the ratchet 54 with the pawl 44 . in general , the apparatus will be used as follows . the handle 60 is grasped and the ratchet 54 pivoted in a counterclockwise direction as viewed in the figures . the arms 40 will then descend about pivot point 42 until they engage in the extensions 58 which serve to prevent the arms 40 from striking the fingers of the operator engaging the handle 60 . the pivot pin 30 of the tool 24 may then be inserted in the notches 46 and upward pressure applied to the handle 26 to break the lower bead . if there is insufficient movement permitted to break the lower bead , the operator need only lower the handle 26 to the solid line position illustrated in fig1 and push axially on the handle 26 . the presence of the partial hook 46 precludes disengagement of the pin 30 from the notches 46 so that the axial force will cause counterclockwise rotation of the arms 40 about the pivot 42 . as a consequence , the pawl 44 will be moved upwardly on the ratchet 54 . when pressure is relieved , the arms 40 will descend until the nose 58 of the pawl 44 engages one of the teeth 56 thereby precluding further downward movement of the arms 40 . as a consequence , the position of the notches 46 will be elevated thereby increasing the height of the path of travel of the bead breaker shoe 36 . upward pressure may then be applied to the handle 26 to break the bead . from the foregoing , it will be appreciated that the tire changing apparatus made according to the invention may be easily utilized by an operator and requires little or no time and effort to adjust the position of the tool during lower bead breaking operations when there is insufficient throw .