Tire Pressure Monitoring
are these gadgets worth the money? in 10 years on the road we've lost 4 tires, they went flat and we didn't know it until it was too late would a tpms warn us of a flat before the tire disintegr...
Forum Discussion
As a general rule (i.e. I'm sure somebody could find an exception), the TPMS senders that are inside the tire have centrifugal switches of some sort and operate only when the wheel is turning above a certain speed, and do not have replaceable batteries. As already noted, the TST sensors transmit all the time regardless of tire rotation. They shut off when removed from the wheel. The auto industry is transitioning to "indirect" tire pressure sensing using the wheel speed sensors already in place for the ABS system. The advantage for the end user is no battery hassles, and the disadvantage is reduced accuracy. The advantage for the auto industry is that the indirect system is free on a per-car basis because it's all software.
