A frequent comment to Bike-Seal/Auto-Seal is “Ah, but I have a Tyre Pressure System that checks the pressures, so your product will block this up……” WRONG!!
Most OE TPMS’s work on a ‘frequency of rotation’ system. Generally there are two types. One that works directly from the hub and linked with the ABS system, if present.
The second, is a plastic housing located on the inside of each rim. They are attached to the inside of the tyre valve, via a collar or directly screwed into an extended Schrader valve. The housing contains a battery and circuit board, and is filled with a hardened compound to seal against the elements and corrosion. The collar system is widely regarded as superior, as it allows for movement, enabling the housing to be drawn up against the inside of the rim, following its contours for greater protection and security of the unit.
As said, most OE systems work on ‘frequency of rotation’ of the wheel. They ‘talk’ via radio frequency to a vehicle ECU.
It is the ECU that enables a numeric value, based on its programming, which is no more than a distance/circumference calculation.
HOW IT WORKS