Tire pressure monitoring system

In reading through my manual (yea, some people do that), I was intrigued by the TPMS. It says it uses RF to transmit from a module attached to the inside of the rim to a receiver in the car. They explain how to properly replace tires so you don't damage this module, etc.

The only thing they don't get in to is battery life of these modules. I would assume the standard 5 year lithium, but I don't know? Heck, do they even use batteries, or do they convert centrifugal force to electricity somehow ?

Reply to
Mark
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I just bought a new Explorer with these thing on them. I too have the same question. Just how long does the battery last and how do you replace them? The manual was pretty poor in this area.

I was a little peeved when I read the manual and it mentioned that the locknut around the valve stem had to be removed/loosened before changing the tire or else the sensor will be broken/destroyed.. How could they design something like that! I can just see me going in to my local mechanic to rotate the tires and then finding out all 4 sensors are broken because the locknut wasnt loosened. Also, I can just see me expalining to the tire guy that i want the batteries replaced. I think this is one of those gadgets that will stop working right after the first tire rotation or battery replacement. Good idea, bad implementation.

I had also read in the paper that the NTSA (is that the agency?) is pretty close to making tire sensors required on all new cars... So we'll all have a new item added to our maintence schedule. At 100,000 miles, replace batteries :-)

dickm

Reply to
dicko

Wow, if people need crap like this to drive their car... I can't imagine they've ever bothered to, say, check the oil. Underinflated (enough to be an issue) tires are noticably low. No gauge or anything needed except a pair of eyes (attached to a head that isn't shoved up one's own ass, cellphone, children or whatever)

Hey, those same pair of eyes were the ones that told me those Firestone Radial ATXs weren't looking right at the stickered 26 PSI - and they recieved 30-32 psi all around.

I guess these are for the same kind of people who whip their SUVs around at highway speeds - ignoring 6th grade physics entirely.

JS

Reply to
Jacob Suter

anyone get last Sunday's Chicago Tribune. I believe it was an article in the automotive section describing how they work and the possibly of forthcoming regulations.

evidently, there are a lot of accidents caused by poorly inflated tires.

dickm

Reply to
dicko

Interesting that Ford chose the remote sensor implementation on this. Earlier I thought I read they were going to use a different system that used individual wheel speed (via the ABS system) to infer that a tire was low. There were complaints from the "experts" that the speed method was inadequte. I guess Ford changed their mind?

Reply to
DriveSpy

I suppose they could use some type of RF source/receiver in the car and a passive sensor in the wheel. This would be similar to the PATS key transmitter and would require no sensor battery. But the distance involved is considerably greater than with the ignition key which would require more RF power. Hmmmmm.

Reply to
DriveSpy

Ford has used the wheel speed differential method on some models.... most notably the Windstar. The system was a bit troublesome and required occasional recalibration (easily done but a PITA none-the-less).

I will agree with Jacob..... the only reason we need gew-gaws is because too many people are either lazy or have abdicated their God given common sense. Cars are simply machines - as such, they need careful attention to be working at their best. Odd that most folks will shower copious amounts of love attention and money upon their toys and ignore the machines that can kill them in a heartbeat.

For dicko..... when tires are rotated, they stay on their wheels... no chance for sensor damage. I can find out what the "advertised" battery life is, if you like but the system will warn when battery life is getting low (of course most people will simply ignore the warning and kvetch about the consequences). A good shop will check tire pressures at every service..... Good tire shops will have people that follow industry trends. Good shops have good people who deserve to be paid good.

Reply to
Jim Warman

Why would you take the tires off the rims to rotate them ?

If your tire shop is doing that (and charging you for it) you need to find a new one F A S T !!!

Reply to
Chief_Wiggum

I made a mistake when i typed that. Didnt have the brain in gear.... Why not just say, "anytime the tires have to be removed".

My point is that having to tell the tire changer "here's the owner's manual, go read it before changing the tire" is not conducive to having a high survival rate of the sensor. I just think its poor design on Ford's part.

Now, 10 years down the line when all cars have this feature and everyone is used to removing the locknut on the valve stem before changing the tire, everything should be fine. Its just at the very beginning where there will be problems.

BTW here's the quote form the manual: "It is recommended that you always have your tires serviced by a dealer or qualified technician".

The following part is in big bold letters: "Each road tire is equipped with a tire pressure sensor mounted on the wheel inside the the tire connected to the valve stem. The tire pressue sensor must be unbolted from the wheel prior to tire removal. The sensor can be removed by loosening the nut at the valve stem. Failure to remove the sensor may damage it."

Back to regular typeface: "The rubber grommet between the wheel and the tire pressure sensor needs to be replaced when any tire is changed to minimize air leaks".

dickm

Reply to
dicko

Oh, I'll grant you it sounds like a recipe for disaster! Especially for the second or third owner of the truck down the road, who may not even have the manual and wouldn't have any way of knowing about the potential problem.

But, for now all you can do is make SURE that anytime you take the truck in for tire service that involves removal of the tire, you tell them about it, and inform them if they break it, they own it !

It seems like ther's about 1,000 other ways they could have implemented it though. What about another valve-stem like protrusion in the rim where you could actually remove the cap, and replace the battery without dismounting the tire ? Or something that comes out under the hubcap. or even the BACK of the rim.

Well, anyway since I don't have 'em on my truck, it's of no concern to me right now :) If I want them I'll have to go the JC Whitney route !

good luck with yours !

Reply to
Chief_Wiggum

Well, it's now a requirement on all new vehicles. So, tire shops won't have a choice but to familiarze themselves with it and how it works on all the different models/versions.

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Reply to
Mark

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