Cheapest source of inside-tire pressure transmitters?

General Discussion
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Triedaq, The ABS Systems Work Well For Us, Too. For Example, My Son Had A Slow Leak In A Tire And It Would Get A Couple Of Pounds Low And Set Off The Alert. He’d Air It Up And Would Go For A Couple Of Weeks Until The Scenerio Would Repeat. He Fixed It By Plugging A Nail Hole.

Those systems utilize the already existing ABS wheel speed sensors, located at each wheel. A tire that’s low on air will not turn with the same speed as the others and the system senses that and alerts the driver. It isn’t designed to tell which tire is the culprit or what the tire pressure is. Road vibration should not set the thing off.

The TPMS with in-the-tire sensors utilize little battery powered transmitters that measure pressure and transmit the information to the dreive, via the the instrument panel display. Here again, if one tire is out of whack with the others, a warning alerts the driver.

The problem is that each time a tire/wheel changes its location on the vehicle then the TPMS system has to be reset to relearn the location of that tire/wheel/sensor or it could indicate correct pressures but give the driver wrong tire location information. So if a tire is at RF and moves to RR the TPMS has no idea that it moved until a human tells it through the underdash socket using a scan tool. It can also be accomplished by the DIYer using a procedure outlined in the Owner’s Manual. It’s tedious (I’ve done it), but requires no tools, except a compressor and tire gauge.

Two things I don’t like about the newer TPMS system like my wife’s car has.
Failure to reset the system when moving tires/wheels gives some wrong information.

Also, those batteries don’t last forever, they alert when batteries expire, they’re fairly expensive, there’s 4 of them, and you’ve got to unmount the tire to replace them. I just thought of something, else. If the system has not been properly reset then a person could change the wrong sensor thinking it’s kaput.

Too complicated for me. I check my pressure regularly. Just let me know if I’m getting a flat. I can do the rest. I think the ABS system is Genius and uses hardware already installed.

CSA

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“Did you check the pressure of all four tires to see if any were low?”
@Robert Gift–I didn’t have a tire pressure gauge with me. This was a vehicle from my institution’s fleet. My own vehicles, one of which was a Ford Windstar that was a year or so older than the one belonging to my institution did not have a low tire pressure warning system. I know that it is hard to judge whether or not a tire is inflated by how it looks. I did kick the tires to see if the thump for each tire seemed to be the same–not accurate, but at least I thought I could spot a really low tire. As I said, we reset the light and in the remaining 250 miles back home, the light didn’t come on again. The vehicle didn’t seem to pull or drive like it had a low tire. I did leave a note for the service personnel explaining what had happened when I turned the vehicle in at 4:00 a.m. in the morning.
I keep a tire pressure gauge in each of my vehicles and check the pressure at least monthly. I always treated my institution’s vehicles as if they were my own, but I didn’t carry a tire pressure gauge or any other tools when I used the vehicles to attend conventions and conferences.

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I was skeptical at first about TPMS. I have everything that I need for tires including a compressor, a balancer, a supply of wheel weights, replacement tire valves, tire irons and a bead breaker and didn’t at first think that I needed any government mandated assistance regarding tires. Since then it has happened twice that the TPMS warned me before I would discover for myself that a tire was low due to a puncturing object. I like that I can more frequently check tire pressures for several days or even weeks after installing a repair plug.