Part of Lesson Plan: **Tire Mounting Part 1 (updated) by Robert Thayer
Activity Overview / Details
I tell the students that I will now show them how to do dismount and mount an automotive tire on a tire changing machine. I ask them to head out to the shop, ensuring beforehand that they have proper eye protection, safe dress, and close-toed shoes. Once at the tire machine, I begin my demonstration using a tire/rim combination from a vehicle in the shop. I demonstrate the steps slowly and carefully, making sure students can see what I am doing. As I am working, I use the proper terms for each part of the tire and tire machine. I use a basic, upright machine, very similar to the Hunter TCX505 tire changer. These are the steps:
___ REMOVE all wheel weights from both the inside and outside of the rim. SAVE the old wheel weights for wheel balancing.
___ REMOVE the valve core from the valve stem with the valve core tool. HOLD both the tool and the core tightly during removal. WARNING: The air pressure behind the core will be very strong.
___ PLACE the core in a safe place for later installation.
___ PLACE the tire in the bead breaker located on the side of the machine, MAKING SURE the valve stem is always pointing straight up or straight down, otherwise you might damage the tire pressure monitor.
___ BREAK the bead in 2 places 180 degrees opposite from each other, on both sides of the rim. Afterwards, you may need to use your hands to push the bead completely away from the rim.
___ PLACE the rim on the tire machine turntable
___ SECURE the rim to the machine using the correct foot pedal either by clamping the rim from the inside or the outside. NOTE: If it is a steel rim, clamp it from the outside in. If it is an aluminum or chrome rim, clamp it from the inside out. NOTE: Make sure the rim is level and tight.
___ PUT some tire soap/lubricant all the way around the upper bead, between the bead and the rim.
___ BACK-OFF the adjustment knob that controls the bead remover (in and out), so that the remover can go all the way towards the center of the rim.
___ LOOSEN the up-an-down locking lever on the bead remover.
___ PLACE the bead remover knuckle onto the edge of the rim, all the way down and in
___ LOCK the arm in place.
___ TURN the in-and-out knob until it contacts the bead remover, and then TIGHTEN it a little bit more, until the remover is a close as possible to the rim without actually touching it.
___ FIND the tire iron located towards the bottom of the machine, and PLACE it against the small curved part of the knuckle,
___ REACH DOWN with the iron and HOOK the iron under the top bead of the tire and PRY the bead over the rim.
___ ROTATE the turntable slightly, until the bead will stay over the rim by itself.
___ REMOVE the tire iron.
___ FINISH ROTATING the turntable until the upper bead is removed. ASK for help with this step, if necessary.
___ LIFT the tire up by hand, and HOOK the iron under the lower bead of the tire, PRY the bead over the rim.
___ ROTATE the turntable until the lower bead is removed.
___ SWING the remover out of the way, and LIFT the tire off the rim and place the tire on the ground.
___ CLAMP whatever rim you will be using onto the turntable. For demonstration purposes, you could use the rim that is currently on the machine. If there is an electronic tire pressure monitor installed on the rim, point that out.
___ REMOVE any dirt or rust from the rim with a wire brush
___ If necessary or desired, REPLACE the valve stem at this time, using a valve stem remover/installer.
___ REMOVE any dirt from the bead of the tire you will be using, and MAKE SURE the bead is not damaged.
___ LUBRICATE both beads of the tire, and the upper edge of the rim.
___ Without changing the in-and-out or up-and-down adjustments of the bead remover, PLACE the tire over the rim, and PLACE the bead remover up against the rim, as described earlier.
___ USE your right hand to PUSH the lower bead of the tire against the bead remover the knuckle. This is important: MAKE SURE that half of the bead is positioned over the knuckle and half of the bead is positioned under the knuckle.
___ ROTATE the turntable with the foot lever until the lower bead goes completely over the rim. USE your left hand to push down on the tire, and HELP the tire rotate with the rim. DO NOT let the tire slip against the rim. ASK for help with this step, if necessary
___ REPEAT this process for the upper bead. NOTE: installing the upper bead is usually harder than the lower bead.
___ UNCLAMP the rim from the turntable, if you are using a chrome or aluminum rim.
___ CLAMP the machine’s inflator hose over the valve stem, using the locking clip at the end of the hose.
___ USE the foot pedal at the left of the machine to FORCE AIR into the tire to seat the bead. CAUTION: When the bead seats, it can make a very loud popping noise – WARN people in the surrounding area that you are seating the bead. If the bead will not seat, you may need to ADD more lubricant to the bead or rim. You also may need to PUSH on certain parts of the tire to help it seat. ASK for help with this step, if necessary
___ REINSTALL the valve core using the valve core tool; MAKE sure the core is tight. 4 ft/lbs is the correct torque.
___ ADD the recommended pressure (found on the vehicle's tire placard) to the tire by using the tire machine’s inflater and inflater gauge.
Take any appropriate questions students may have during and at the conclusion of the demonstration. Clean up the tire machine and the area around it. Return all tools and equipment to their proper locations. Tell students to return to their desks.
Note: If any student is bored, chatting, disruptive or distracting during my demonstrations, I may ask him or her to perform a step or two of the procedure, in an effort to redirect their attention, engage them, and get them back on track.
Materials / Resource
- Hunter TCX 505 Tire Changer [ Go to Site ] A tire machine similar to the one described in this lesson.
- Tire Machine Procedures Handout [ Download ] This is a simple handout covering the procedures identified in the activity for projection or just for a handout if need be.
- Tire Changing Machine Worksheet with instructions [ Download ] This is a tire machine worksheet for students to complete, with step-by-step instructions on project set-up, dismounting, mounting, quality control and clean up.