Tire Pressure Monitoring Systems (TPMS)
 

I can't justify spending X $$$ to add more complexity to my life; especially when you can't replace the batteries and have to buy new sensors. WTF?

Right now, I simply carry a VERY good bicycle tire pump in my car boot and top off my tires every other gas fillup.

If your car has a TPMS, how frequently are your topping off your tires? Can you estimate how much air leaks out weekly? Seems I'm losing 1lb a week.

I check my tyre pressures every couple of weeks. That pound you loose is probably as you disconnect the pump!

A TPMS for the Sonic is under $25 for an AC Delco. The battery is good for 7 to 10 years.

Look at it like a smoke detector. The life time battery models mean never having get the ladder out to replace a battery. Replacing a battery of a TPMS every 2 to 3 years would be more hassle. Then there could be other components on the TPMS that have worn out and near dead by the time the battery dies, like the smoke detector.

I find the fact that the system on the Sonic only warns me when a tire is way low more of an annoyance that the sensors. I don't even know which tire is low. Which works for learning about nails in the tire. It just would be nice to get an actual reading for each tire, as our new Camry does, which does mean having to relearn the senors after a tire rotation though.

Tire pressures will drop with ambient temperatures as fall and winter approach. I have seen them actually rise in spring. 1 pound a week might be a problem, unless every tire is dropping that same amount. Then I would suspect cooler temperatures since it is almost beyond probability to have 4 identical slow leaks.

New cars with everything new don't leak much at all. Maybe a pound a month based on my new car. I do clean the bead area thoroughly when I replace wheels with used. If one is leaking at a greater weight than the others, beast way to find it is a water tank. I found one of my rims on the Mirage was leaking around one of the wheel weights (clip on). I took it back to Costco and had them replace that wheel weight with a stick on weight, problem solved. Since I cleaned the bead area of the rims before having the tires installed, they hold air as well as new rims.

As far as TPMS systems, they will help those who don't monitor tire pressures or encounter a slow leak from a nail or other sharp objects. I let the wife's Sorento run 5k miles with a nail in the tire since it was at the edge of the tread when they could not repair it. I have a Craftsman compressor (30gal 5 HP) that sits just inside of my garage door. I could not tell you if the nail had penetrated to the inside of the tire, but the pressure did not drop, so I left it alone and she traded the car in with 55k miles on the original tires. Every tire was down to 3/32 inch tread depth, after running 40 LBS pressure since new.

Just had my tyres changed and I realised the TPMS works off the abs sensor. Quite clever, it measures each wheel rotation and if one it going slightly faster than the rest, it would tell me a tyre is low. Never had to check them as yet though.

My car also has the wheel sensor set-up and it measures rotation relative to each wheel. That way you can swap any rims without ever worrying about reprogramming the TPMS (dealers charge around $65). The only downside is that it doesn't show the actual pressure in each tire.

Here in Canada, where you have to have winter tires and summer tires; having a set of winter rims with tires is so much more convenient. If I had a TPMS, I would have to reprogram it every time the wheels are swapped, or have an error light for half a year. People usually have the rim that comes with the car and change the tires; and everyone wants to change their tires when the first snow falls and by that time all the shops are booked for weeks with people getting their tires changed.

The relearning tool for your car brand might be under $100. Worth it if you are switching rims regularly.

They're supposed to be easy to reset, given how frequently tyres can loose air. Mine is just a press of a button on the touchscreen, although nothing appeared when I changed my rims, it's recommended you recalibrate if your changing tyres and/or rotating wheels etc.

The relearning process is only needed when the wheels are rotated or for new sensors. This tells the system where each sensor is located.

It was once possible to relearn a sensor on GM's by dropping the pressure, and then reinflating the tire. I've read their were sensors that could be triggered to relearn by just placing a strong magnet near the valve stem. Now it seems a tool that puts out a short signal is needed.

Since the Sonic doesn't show psi readings, nor alert for individual tires, I've never bothered having the sensors relearned after rotating the wheels.

Your sonic probably uses indirect TPMS like mine, they are more common, and don't display individual tyre pressures etc.

https://en.m.wikipedia.org/wiki/Tire...itoring_system