Do your technicians understand terms like concentricity or know how to properly unfurl a stiff bead? Could they explain why we use reverse drop center adapters on certain wheels? If not, it may be time for a quick refresher! The common thread is that these all relate to properly demounting tires.
When it comes to tire changers, rim clamp and pedestal types handle demounting differently. You need to make sure newer techs learn the particular steps for using each machine properly. In both cases, have a TPMS service pack chart, lug nut torque chart, replacement sensors and an updated TPMS programmer near the tire station. Most importantly, technicians should know not to start a job until they have the tools and parts ready to go.
If you are demounting with a rim clamp, start by installing plastic protectors on the clamps, the side shovel bead breaker and the pry bar. Always start the prying either 90 or 180 degrees away from the valve stem or any sensor that may be there. Never try wedging right up on the stem or sensor itself – that’s just asking for trouble. Once you’ve cracked the bead free, take a quick peek behind to check if there’s a band-mounted sensor in place and note what the drop center position is on that particular wheel.
Open the clamps, position the wheel with the drop center at the top, and close the clamps onto the wheel flange. Align the duckhead with the sensor or valve stem, then work the top tire bead over the duckhead using the pry bar. Rotate the tabletop in reverse to let the tire bead unfurl, allowing the inner liner to lay on the pry bar.
Next, rotate the tire forward to remove the top bead, then maneuver the tabletop to position the sensor under the duckhead. Slide the pry bar down, catch the bottom tire bead, lift and position it into the drop center. Rotate forward to remove the bottom bead. For steel sidewall tires, use the unfurling technique to catch the bottom bead on the duckhead.
Afterward, ensure a clean bead seat by brushing off debris with a steel wire brush. Referring to the TPMS chart, replace the TPMS service pack using the appropriate tools and torque values.
Now, when using a pedestal tire changer, secure the wheel through the centerbore using the pistol tool. You can protect the wheel finish with plastic covers. For reversed-mount wheels, install a reversed wheel adapter through the lug holes. For chrome-clad wheels, use a chrome wheel adapter. Secure the wheel, break the tire beads with rollers, and remove the tire beads with the demount head.