When selecting a tire changer you must make sure the wheel clamping ability is large enough to service the size of wheels you intend on working with, if you are considering a jaw clamping design make sure the external clamping range is adequate, most manufactures of tire changers list the internal clamping capacity, however to clamp aluminum wheels without any visible damage, or to clamp a reverse drop center rim you should clamp them externally. A rim with a reverse drop center will need to be mounted up side down to keep the drop center closer to the top bead.
The next consideration should be the outside tire capacity of the changer, the upright column that supports the swing arm for the mounting head needs to be mounted far enough back to allow the overall diameter of the tire to clear. If you intend on changing larger truck tires this will need to accommodate up to a 35" tire or even larger.
Consider a tire changer with an air assist arm if you are going to work with low profile tires, the assist arm should have the ability to follow the tire as it rotates to assist in holding the tire bead in the drop center of the rim to allow mounting the tire without damaging the tire bead. The arm should be equipped with an adapter to allow the rim to be depressed downward while clamping to allow the rim to be clamped externally without damage.
The side shovel to break down the bead should have the capacity of the largest wheel you will be servicing, some truck and performance wheels get very wide.
Other options and features to be considered are :
Motor size to provide enough torque to service low profile and truck tires.
Mount/dismount head design, make sure polymer inserts are available or a polymer head is available.
Tire clamping jaws have protective covers available for rim protection or choose a center clamping design that will not damage the wheel.
The inflation system is capable of inflating all types of rims, the inflation jets must be properly aimed at the tire bead, some new changers are equipped with a blast type inflation that is similar to the Cheetah air inflation system.
The bead lever design can make a difference when changing low profile tires, some new style tire changers offer lever less tool heads, a pneumatic lever flips down to reach under the bead for ease of dismounting.
Service, make sure there is service available for the tire changer you select, many of the imported units have no parts available for servicing the tire changer in the future.
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