Tire pressure sensor?..

[JoshikusIII]

So I took my truck to the dealership for the first time for a once over and to replace a brake/accel pedal relay switch... after a few days my tire pressure light and warning starts going off, so I do the normal and check everything...45 in the back and the fronts were at 47 so I bumped up to 51, it seems to handle better and get better mileage. And a week later the light is still on. 65 seems a little high to me which is what is recommended on the side of the tire.

So my questions are why is the sensor not triggering off with legitimate psi and after a visit to the dealer and did they change the info in the computer to the specs on the side of my tires since they are no longer the stock size?

Also what are you other guys running for psi on your 285/70's?

 

[jeepguy_1980]

The side of the tire is not what you should service your tires to. The pressure range you need is on a sticker in the driver's door jamb.

 

[UNBROKEN]

Wrong...the pressure you run is dictated by the tire once you don't run stock tires.

 

[jeepguy_1980]

Wrong...the pressure you run is dictated by the tire once you don't run stock tires.

I missed the whole aftermarket tire part. But the side wall number still isn't the optimal pressure, but it is probably more accurate than the door jamb number.

 

[TRCM]

Wrong...the pressure you run is dictated by the tire once you don't run stock tires.

Well, I'd say you are wrong as well.

The pressure on the side of the tire is for IF you are running the tire at MAX load, which rarely happens.

It even say "Max pressure @ max load" below that max load, you can run any pressure you want within reason that gets you a full contact patch of rubber to the road, and max pressure will NOT do that.


Ever wonder why the door says 35 psi, but the tire says 45 psi on your stock tires ??? Cuz the door is based on many things (comfort, load, handling, etc), but the sidewall is based on the max load the tire is rated for only.

I would not run less than 75% of the max rating, but I would not run max rating either unless I was very heavily loaded. On a 1500 like ours, IF you are loaded heavy enough to need to run max air pressure in your tires, chances are very good you are over the trucks weight ratings anyway.


As an example, on my 97 3500 ctd dually, if I ran enough weight to need all 6 tires @ max pressure, I'd be @ 12k+, and the truck was only rated to carry 10,500, so I'd be way over the rating.

 

[UNBROKEN]

My statement is in fact 100% correct. Once you no longer run oem tires the pressure is dictated by the tire itself...period. Different tires will run different pressures at different loads...that should go without saying.
I can write an 10 paragraph addendum if necessary to specify when, what, where and how the tire will dictate the pressure including spelling out and including graphs and pictures showing how to measure contact patch front vs rear etc if you'd like? Should I include max load ratings in my thesis as well?

 

[Razzaa]

My statement is in fact 100% correct. Once you no longer run oem tires the pressure is dictated by the tire itself...period. Different tires will run different pressures at different loads...that should go without saying.
I can write an 10 paragraph addendum if necessary to specify when, what, where and how the tire will dictate the pressure including spelling out and including graphs and pictures showing how to measure contact patch front vs rear etc if you'd like? Should I include max load ratings in my thesis as well?

Please start writing this 10 page report. It will be due Monday. Of course we would like max load ratings in your thesis but you must provide evidence proving your theory. I will be waiting with great excitement for a 10 page report about tires.

 

[TRCM]

My statement is in fact 100% correct. Once you no longer run oem tires the pressure is dictated by the tire itself...period. Different tires will run different pressures at different loads...that should go without saying.
I can write an 10 paragraph addendum if necessary to specify when, what, where and how the tire will dictate the pressure including spelling out and including graphs and pictures showing how to measure contact patch front vs rear etc if you'd like? Should I include max load ratings in my thesis as well?

I could have done the same thing, and have before on other sites. (Well, maybe not 10 pages, but definitely a lot of typing)

What you said is correct....but the way it is so simply stated will cause 99% of the people out there to think you are saying to go by the only rating that is on the side of the tire...the MAX rating.

And yes, I agree it should 'go without saying', but the sad part is, it doesn't. Every time I have seen a post about tire pressures, whether it be on a truck site for truck tires, or a fishing site for boat trailer tires, 99% of the people say to run the max pressure on the sidewall, which is incorrect.

I and everyone else who replied so far assumed that is what you meant because it is so prevalent an idea (albeit an incorrect one). Because you simply said the pressure was dictated by the tire, and didn't bother to explain what you meant, we all assumed you meant the only rating on the tire sidewall these days, which is the max pressure @ max load.

So, yes, the pressure is dictated by the non-oem tires, but there is no way to know what pressure to run by looking at the tire, except in cases of running the max load. So, you'd still have to check your contact patch, and in most cases, the factory pressure is close.

Case in point, on that same 97 3500 I had, the door said to run 75 psi front and 65 psi rear. Well, I did run 75 psi in the front, but the rear tires I ran....get this....25 psi in all 4 tires, cuz it gave me a non-bouncy ride AND a full contact patch with no scuffing between the inner and outer tires.

Now, when I was carrying a load or pulling my gooseneck trailer, I'd bump them up to 45.

 

[chrisb38002]

Here is one to think about, and let someone explain.
I have had 3 Ram trucks, 03, 11, and 13. All had different tire sizes; 265/70R17, 275/60R20, and 285/45R22. Also ran some 285/55R20 tires for a while.
The different tires all had different max pressure specs on the tires, but each of the trucks had 35psi on the sticker, and that is where the tires were set. Never had any uneven wear or problems with any of them, except for the usual crappy goodyears.

 

[TRCM]

Easy to explain...as I said above, the door jamb is a combination of many things - comfort, handling, weight, etc., and that is why they all had the same pressure since all weighed the same and rode the same.

But the different tire sizes can carry a different weight @ max pressure, hence the different ratings on the different tire sizes.

 

[JoshikusIII]

Wow quite a debate. So basically your saying my pressure is fine (which I knew it was) perhaps on the high side and my sensor is most likely malfunctioning.

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[ramflava]

Mine truck started giving my a tire pressure low reading as well. I went and had the tires put at the appropriate pressure and the next day it said the pressure was wrong again even though the pressure was the same.

The dealership had to flash update the computer with solved many issues I was having. You might want to talk to them about that.

 

[Designflaw]

My statement is in fact 100% correct. Once you no longer run oem tires the pressure is dictated by the tire itself...period. Different tires will run different pressures at different loads...that should go without saying.
I can write an 10 paragraph addendum if necessary to specify when, what, where and how the tire will dictate the pressure including spelling out and including graphs and pictures showing how to measure contact patch front vs rear etc if you'd like? Should I include max load ratings in my thesis as well?

Wow, I generally appreciate most of your posts and your experience with the dodge but to state it like fact is sad, especially when for a general passenger tie you are incorrect for the most part. So, please post some of your facts and graphs please. Not racing, but general passenger long Term travel and pressure and how you come you your final prognosis please.

I will then post quotes from Pirelli, Cooper Tire (2nd largest tire manufacturer in the world), Tire tack, Dunlop, and BFG, so you will know there there opinion. Then I will explain pounds per square inch as a measure of capacity. Why in general Again, OEM tires are cost prohibitive or unavailable to the civilian market as well as not worth the purchase.

Long story short, they all state to go by the vehicle manufacturers recommendation. Again, as general start point and that the side wall maximum is just that

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[UNBROKEN]

I actually corner scaled my truck and emailed with a guy from Pirelli about the optimum pressure for my truck. 47 front, 42 rear. Verified with black shoe polish and a smooth concrete floor...that's all I had at the time.
None of which is on the tire or the door.
What's your point?

And what OEM tires are unavailable to the "civilian" market?

 

[smiley]

Wow, I generally appreciate most of your posts and your experience with the dodge but to state it like fact is sad, especially when for a general passenger tie you are incorrect for the most part. So, please post some of your facts and graphs please. Not racing, but general passenger long Term travel and pressure and how you come you your final prognosis please.

I will then post quotes from Pirelli, Cooper Tire (2nd largest tire manufacturer in the world), Tire tack, Dunlop, and BFG, so you will know there there opinion. Then I will explain pounds per square inch as a measure of capacity. Why in general Again, OEM tires are cost prohibitive or unavailable to the civilian market as well as not worth the purchase.

Long story short, they all state to go by the vehicle manufacturers recommendation. Again, as general start point and that the side wall maximum is just that

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I tend to agree the door jamb means very little and I will always us my discretion. That being said 35 seems to be a good number if not sure on most passenger vehicles. Had the owners of Ford Explorers used their brain they would not have had all those issues with firestones. Those vehicles said 26psi on the door jamb. Well then those people did not check them and I would guess some ran them at 20 something and bam blow outs.
With these new sensors which are a result of those blowouts a big problem is moisture. I would highly recommend you get them filled with nitrogen if they are not already then there is less up and down and moisture is nearly eliminated.


Where did you get that Cooper is second largest in the world? US maybe but in the world no way. Michelin and Bridgestone are largest. Here is table of them by size.

$miley

 

[loveracing1988]

Wrong...the pressure you run is dictated by the tire once you don't run stock tires.

So what your saying is if I had a Ford Ranger, and I put load range E tires on it, I should be running 80 psi in all of the tires?

Back to the op, no matter what tires you put on your truck the sensors don't know that, all they see is psi, which will be the same measurement wise in every tire, if it wants 40 psi in your stock tires, it will want 40 psi in your current tires, so you have a problem with one of your sensors or a problem with the computer, either way a dealer should be fixing it.

 

[Designflaw]

Where did you get that Cooper is second largest in the world? US maybe but in the world no way. Michelin and Bridgestone are largest. Here is table of them by size.

$miley

Drunken ramblings of a guy that was a tire tech 20 years ago while in college lol.

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[UNBROKEN]

I guess I'll be more specific in every damn post I make from now on since apparently common sense has gone the way of the dodo bird.
Did I make a generic statement? Yes
Did I think most people had enough sense to understand? Yes
Was I wrong? Absolutely.

I forgot this is the hold my hand a show me every step of the way generation.

 

[TRCM]

I guess I'll be more specific in every damn post I make from now on since apparently common sense has gone the way of the dodo bird.
Did I make a generic statement? Yes
Did I think most people had enough sense to understand? Yes
Was I wrong? Absolutely.

I forgot this is the hold my hand a show me every step of the way generation.

Don't get mad at us.....we, or at least I, don't know you from Adam, and as such, I take what you say as you say it, cuz I have no way to know what you really meant.

All I do know is 999 out of 1000 times when someone makes the statement you did, they actually mean the max pressure rating on the sidewall, which is wrong, so naturally, it was thought you meant that too.


You do have to watch what you say to avoid being taken the wrong way in today's society.

At least some of us know enough to not walk in a bar and say "I want to have sex" without adding "with a woman" onto the end of it.

Not doing so these days could you get your butt kicked, or you could end up in bed with someone who has the same plumbing as you.........who knows.

 

[Dale_K]

I've never thought about it before but I guess the TPMS will come on if the pressure is too high the same way as when it's too low. Over 50 psi might trigger it. The OP could put the pressures back to the sticker (right or wrong) and drive the truck for a while to see if the light turns off.

I had a 2012 Jeep with the same TPMS and bought a module that allowed me to set the TPMS threshold to whatever I wanted, including zero, which would turn off the light permamently.