Amusing TMPS observation

[E365]

Originally Posted by Rand
its nice if you pick up a nail. Saved me once.. I was down to 14psi in 5min trip home from barber.



+1. Had this last spring. TPMS light goes on at 55 MPH and I was pulled over within about 60 seconds. Tire was about half flat when I got out of the car. A few minutes later and it was essentially flat as could be.

The TPMS warning without-question saved me from needing a new tire from driving on a flat.

 

[ekpolk]

Originally Posted by BMWTurboDzl
Originally Posted by JohnnyJohnson
Good grief how did I ever get along without these for almost 60 years of driving

TPMS was a response to the Ford Firestone tire fiasco. People were driving around on underinflated tires and the tires themselves weren't constructed well enough.

Absolutely correct. Usually, the "knee jerk" pseudo-legal responses to such disasters turn out to be utterly useless make-work CYA rituals that actually neither help nor save anyone. In this case, however, the response has actually proven to be surprisingly helpful and practical. I too have received critical early warning from TPMS that saved me from being stranded on the side of the road. I get that it's a hassle for those with snow tires on steelies, but it's still worth having.

 

[pdxglocker9mm]

From what i have experienced the systems are a little slow. Like over 20 miles before it alerts. If it was faster acting I would be more impressed. Plus they are usually set to aleart around 75% of full spec so a 32psi tire spec would not alert untill below 24psi which in my opinion is too low.

 

[ekpolk]

Originally Posted by oil_film_movies
. . .And overkill's point about having the reading right on the dash is good when a car does that. A lot of Fords don't, GM likes to put in right on the dash.

Kudos to GM for doing that. In our Toyotas, we make do with the "idiot light" only, but it is still fully worth the "pull over and look now" warning.

 

[4WD]

Yep … I can read all four tires on our GM's dashboards … and I will get a tire pressure warning by email …
(I have sent my wife a text from overseas and sure enough there was a screw in a tire) …

 

[Tomioka]

Originally Posted by dishdude
I like pushing a button and seeing the tire pressure. Sure beats walking around to each tire.


Yep. Cuts pre-trip time in half and unnecessary free air visits.

 

[Skippy722]

Originally Posted by oldhp
Does anybody's tire pressure gauge match the TPM's??? I have a liquid filled $60 gauge.....3 lbs low. My $2 pencil gauge is 2lbs low.


I use an actual gauge once and compare it to the TPMS. If they're within a pound or 2, and they always have been in my case, I don't worry and go only off the TPMS. I add a little extra air to the tires as well... if it calls for 32, it's getting 34-36.

 

[Duffyjr]

I have a fairly nice Longacre and all my sensors read one pound low, close enough for me.

 

[Shannow]

Colorado'r resolution is 4kPA (0.6psi), so there's often an alarming 8kPa-12kPa split across an axle (or pseudo axle in the case of the fronts) that changes with orientation of parking and the angle of the sun.

It's taken some time to adjust to the "wrong" readings that would incite one to take action, but a nail in a tyre over the course of a couple of days makes the system well worthwhile.

 

[OVERKILL]

Originally Posted by pdxglocker9mm
From what i have experienced the systems are a little slow. Like over 20 miles before it alerts. If it was faster acting I would be more impressed. Plus they are usually set to aleart around 75% of full spec so a 32psi tire spec would not alert untill below 24psi which in my opinion is too low.


The Chrysler system is significantly more sensitive than that in terms of deviation from spec pressure. Not sure about other marques.

 

[StevieC]

That's funny...

 

[Benzadmiral]

Originally Posted by OVERKILL
This happened yesterday when I was leaving work.

Background info pertinent to what transpired:
- FCA TMPS is "self learning". New sensors only need to be on the vehicle for a period for the vehicle to auto-learn their location and present the pressure data
- I don't run TMPS sensors in my winter wheels

So, I end up behind a 2019 Grand Cherokee for quite a stint; probably a good 5-10 minutes. My (lacking sensors) SRT picks up the sensors in this Jeep. I get its tire pressures in my cluster. When I parked it of course could no longer find them so now it is doing the whole start of winter "I don't have sensors" thing again, so I have to wait for that to complete and then it will stop bothering me with the alert.

Guess that's an unspoken caveat of a system that self-learns: If it doesn't have its own sensors, it'll associate with others that are in proximity for a long enough duration

What are they, social animals like wolves? ("I'm lost without my pack! Help meeee!")

 

[Benzadmiral]

Originally Posted by Kibitoshin
Originally Posted by dishdude
I like pushing a button and seeing the tire pressure. Sure beats walking around to each tire.


Yep. Cuts pre-trip time in half and unnecessary free air visits.

My gosh, where are you finding free air nowadays? Every station I see here wants $1.00. I bought a portable inflator that plugs into the cigarette lighter and air the tires up that way. I figure it paid for itself long ago.

 

[Benzadmiral]

Originally Posted by ekpolk
Originally Posted by 14Accent
TPMS is nothing but an over-reaction to the whole Ford/Firestone tire issue. I check my tires at least once every oil change, if not more. TPMS is just another among a suite of unnecessary "safety" systems that no one needed for 60 years and don't need now.

Respectfully disagree. As some of the other posters have already indicated, this system in particular, offers actual, real-world, value added for the owner (as opposed to mere CYA for the manufacturer). It's so much better to get a useful early warning of a leaking tire, instead of figuring it out when you hear and feel the "flop-flop-flop" of the flat.

Once I didn't believe in the utility of TPMS. Then in 2016, I think, I was driving at speed on the Interstate and got a "Low Tire Pressure" warning. In fact the TPMS in my Regal showed it in real time: 24 . . . 23 . . . 22 . . . I got off the road fast. By the time I came to a halt, the tire was down to 16. If the system hadn't warned me, I might have found out as ekpolk says, though with a BANG and a crash.

 

[Duffyjr]

Originally Posted by Benzadmiral
Originally Posted by Kibitoshin
Originally Posted by dishdude
I like pushing a button and seeing the tire pressure. Sure beats walking around to each tire.


Yep. Cuts pre-trip time in half and unnecessary free air visits.

My gosh, where are you finding free air nowadays? Every station I see here wants $1.00. I bought a portable inflator that plugs into the cigarette lighter and air the tires up that way. I figure it paid for itself long ago.


Years back you couldn't find free air around here so I got tired of it and the fact that they don't work half the time especially in the winter and bought a Makita mac700 and never looked back. A couple years ago I noticed all those places that charged for air are back to being free now so I asked a guy that owns a Shell were I get gas about it and he said it cost more to keep the coin machine working than it was worth.

 

[Benzadmiral]

Originally Posted by Duffyjr
. . .
Years back you couldn't find free air around here so I got tired of it and the fact that they don't work half the time especially in the winter and bought a Makita mac700 and never looked back. A couple years ago I noticed all those places that charged for air are back to being free now so I asked a guy that owns a Shell were I get gas about it and he said it cost more to keep the coin machine working than it was worth.

Permit me to laugh, loud and long. Of course, here the machines are still in place. If they're broken, the owners don't care and the customers can't be bothered to air up their tires anyway.

 

[pezzy669]

Originally Posted by pdxglocker9mm
From what i have experienced the systems are a little slow. Like over 20 miles before it alerts. If it was faster acting I would be more impressed. Plus they are usually set to aleart around 75% of full spec so a 32psi tire spec would not alert untill below 24psi which in my opinion is too low.



This is typically the more basic TPMS that use the ABS sensors to monitor changes in wheel rotational speeds which are slow to react. The systems that actually read the pressure at the valve stem are pretty instantaneous. I had the ABS sensor system on my '15 Mazda 3 GT - hit a pothole that had the tire flat within 1/4 mile and I already knew I had a flat, the light did not illuminate until ~3/4 mile later when I reached a safe place to pull over. My '09 C300 (direct read) - had another pothole flat and the light was on less than 1/4 mile later.

As for the usefulness - I am a believer. My dearly departed E350 had a slow leak in one of the tires that would lose about 1 psi per day, the low profile tires do not accurately represent low tire pressure by just looking at the tire. After my car sat for a good 7+ days the tire had dropped to 18PSI, just looking at the tire from the outside you would never know it was low.

 

[JTK]

In the case of the TPMS in my 2017 Ram 1500 pickup, the PSIG reading updates and low press warning clears itself as quickly as I can coil the air line back in my garage. No run time or miles driven are required for the system to update. Like I say, if FCA got something right, it's this latest generation of TPMS and system in general. Replacements sensors are cheap and they're plug-n-play provided you use OEM. Aftermarkets will require some intervention.

 

[Garak]

Originally Posted by Duffyjr
Years back you couldn't find free air around here so I got tired of it and the fact that they don't work half the time especially in the winter and bought a Makita mac700 and never looked back. A couple years ago I noticed all those places that charged for air are back to being free now so I asked a guy that owns a Shell were I get gas about it and he said it cost more to keep the coin machine working than it was worth.

I can't speak for the States, but up here, there is a company that will install and maintain air fill stations at no cost to the gas station. The gas station gets a small percentage of the revenue and the rest is split between the company that owns the machine and some charity.