During a vehicle's life its wheels will be exposed to various service environments which will include Dealership Service Centres, Automotive Mechanical Repair Shops, Auto Electricians, and Tyre Fitters. In particular, during tyre replacement procedures there will be many opportunities for the vehicle's TPMS rim mounted sensors to be exposed to damage and also for various types of "TPMS wheel Modules" to actually damage the rubber seal and bead areas of tyres:
At Tyre Fitters there are many "hazards" for TPMS; these include sensor
survival, consumer costs and litigation involving members of the TIA:
In the US practical experience from Dearlerships and members of the Tire Industry Association (TIA) has shown that RF style Valve Stem Mounted and Band Mounted RF Sensor Housings are at a high risk of being damaged by tyre debeading and tyre changing equipment during tyre changing operations. This may involve extra costs for replacement sensors and liability issues for TIA members. The following photos illustrate why the TIA has concerns about liability issues for its members:
The RF Module of Valve Stem Mounted style RF TPMS Sensor
showing tyre bead compression damage:
A key design feature of a rim's profile is its "Dropwell Centre" [1]. A rim's Dropwell Centre dimensions are specifically designed to accommodate tyre fittment onto a rim and subsequent removal and replacement on the rim. The Dropwell Centre allows a portion of a tyre's bead to "drop" into the "well" so that the portion of the tyre's bead directly opposite may be minimally "stretched" over the rim's outer lip to get it on or off the rim without damage to the tyre's bead and air sealing characteristics. Unfortunately the banded style RF TPMS modules completely interfere with a Rim's Dropwell Centre and may cause damage to the tyre's bead and rubber thus compromising the air seal between bead and rim:
The "Banded" Style RF Sensor, showing it obstructing the rim's
Dropwell Centre. Damage to the RF sensor module from the
bead and also damage to the tyre's bead from the module and
sharp edges of the band and its tightener screw may occur:
Notwithstanding damage to the tyre bead from the RF TPMS Modules, the greatest threat of damage is to the RF TPMS Module from the Tyre Changing Equipment:
The TPMS Module's "Enemy Number 1" . . . A typical
Tyre Changer and Debeader Machine is shown with,
the wheel on the right side in the Debeader's press
position:
Closeup Photo of a Tyre Debeader, (alias "TPMS Chopper"):
A major advantage of the VisiTyre technology is the protection it gives to the pressure sensor against mechanical damage. VisiTyre positions its sensor on the exterior reverse side drop centre of the rim, where it is ideally protected against such damage:
A "VisiTyre Enabled Rim" showing the Embedded Rim Sensor Coil
and its location deep inside the protected exterior reverse side
of the rim:
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Notes:
[1.] Rim Terminoligy:
