Today's tire machines are stand-up models that hydraulically assist the tire technician to remove the tire from the rim and replace it. The hydraulics in the machines can either be electrically or pneumatically powered. There are many moving parts on the machine that take the technician through the removal and replacement process at one machine, without having to move around the shop. These tire machines were designed for speed and efficiency as well as limited shop space. The tire's bead is separated from the rim, placed on a clamping turntable, and an adjustable tool bar, pry tool, and the turning motion of the turntable remove the bead of the tire from the wheel. The machines generally have tire lube bottles band-strapped to them to conveniently apply a coat of lubricant to the bead of the tire being installed. They also have some shelf space for valve stem replacement storage and other tools that may be needed. The new tire is placed onto the wheel in an opposite fashion and then air is inflated into the tire, all at the tire machine. Most tire machines do not balance the tires--that has to be performed using another machine. These newer stand-up tire machines are much faster and more efficient than their old manual tire-changer counterparts.
Commonly located on the right side of the machine if you're facing it from the front. The tire is rolled up on the wheel and deflated to the right side of the machine standing vertically. The bead breaker is lined up manually by the technician and strategically aimed near the bead of the tire, but just away from the inside edge of the rim. The bead breaker is activated by a foot pedal on the bottom of the front of the machine (or, in some older models, by a button on the bead breaker handle activated by the thumb of the technician), and is drawn toward the machine using hydraulic pressure to collapse the bead from the wheel. The tire is then turned around manually and the bead on the reverse side of the wheel is separated from the wheel again so that the beads on both sides of the wheel are collapsed before placing it on the turntable.
The turntable is located at the top of the base of the tire machine--low, so that it can be easily worked on by the tech at thigh level. The tire, beads now collapsed inward from the wheel, is placed on the turntable horizontally. Four hydraulic or pneumatic clamps are activated by another foot pedal located near the floor in front of the machine. The clamps can either extend from in to out and clamp the tire from the inside circumference of the wheel, or they can clamp on the outside edge of the wheel moving from out to in. The pedal activates the clamps, and they spread out or in to grip the bottom of the wheel and hold the wheel during the removal process. The other feature the turntable does is turn. Again, another foot pedal at the bottom of the front of the machine turns the table clockwise if you step down on it, and counterclockwise if you place your foot under the foot pedal and lift it upward. This gives the tire technician forward and reverse motion of the turntable.
Once the tire is laying on the turntable and the clamps have locked the wheel, the adjustable tool arm swings up to the top right-side edge of the wheel. There is a metal or plastic curved end of the tool arm (commonly called a duck head because it resembles the head of a duck) that wraps around a 7- or 8-inch-wide area of the top of the wheel rim. The tool arm is spring-loaded and can move up and down easily, and moves from a boom arm that swings back and forth. The boom would swing the arm inward until the tool arm is up to the wheel, then the tool arm would be manually pushed downward on the spring until the duck head is mounted onto the top right side of the rim. Then, there is a locking arm on the tool arm that will hold the spring pressure of the arm to the rim. Now the tool arm and duck head are locked into place. The pry bar or tire tool is set down into the sidewall of the tire, where the bead is separated from the wheel and lifted or pried up over the duck head. The turntable is then activated by foot pedal in a clockwise motion while still holding the pry bar and the top bead of the tire over the duck head. About halfway around the pry bar no longer needs to hold upward pressure of the bead of the tire, and the duck head takes over removing the bead from the wheel. The bottom bead is removed in the same fashion, although this is a little trickier because the width of the tire can sometimes get in the way.
Knowing the foot pedals, their location, and the function they perform is the trickiest part of the tire machine. The more a tire technician uses one, the easier and quicker this becomes. There may be three or four foot pedals in the bottom front of the machine that all operate different functions of the machine, so it's all about coordination. Most of these machines and the foot pedals that operate them have automatic shut-off functions. In other words, if you miss the tire bead when using the bead breaker and accidentally hit the wheel, but do not want to incur damage to it, by releasing the foot pedal that activates the bead breaker, the bead breaker stops the hydraulic pressure. This is the same for the turntable. If the bead slips while the table is turning, releasing the pedal stops the table and gives the technician another chance to start over.
Once the tire is successfully installed on the tire machine, the last step is to inflate it. On the left side of the machine is yet another device and another foot pedal. The device is a pneumatic air hose with an adapter that fits onto the universal valve stems. Air is pumped through the air hose by stepping on the foot pedal. Most machines will also have an air inflation gauge to monitor how much air pressure is being pumped into the tire. Caution is advised during this step as tire beads setting against the wheels can be loud and dangerous if not performed properly. By pressing down on the air inflation with force, the tech can activate a bead-setter purge of air that assists in setting the bead of a flimsy sidewall tire onto a wide rim. The air is purged from both the air hose and from holes on the turntable that blow upward with force to push air into the bottom bead of the tire and force the upper bead onto the wheel. The air inside the tire machine is limited, so once the tech has exhausted the air pressure with the bead setter blast of air, he may have to wait for the pressure to build up inside again before trying again if he wasn't successful the first time.
