Same setup in my 2009. Display shows individual tire that is low.

 

My take on TPMS.....

I don't have it on my Audi, but to be honest, if I did, I think I would see it as a gizmo or a backup / a failsafe or warning.

I would use it as a backup to my owneyes, my checks as have been done historically.

Park aid sensors for example - They're there as a backup, as an aid but that doesn't mean you don't look behind you when you reverese. I've seen too many people rely all too heaily on systems like these only to hit this or that because they haven't paid attention.

I also subscribe to the point made that I can always tell if I'm driving the car and one tyre has lost a decent amount of air and missed the check....the handling gives it away a mile away for me anyway.

On the other hand my wife could be driving with a tyre with maybe 10 psi in it if your lucky and never notice.

Sorry I can't relate to you guys who have TPMS on your Jags, but I still think the point is relevant.

 

I can say the TPMS on a jag are sensible to the temperature variation, if it goes under 45 degree I know I'm gonna have a low tires pressure warning, in the morning, for sure !

and I agree with you rbobzilla Jaguar should have put some more money into this system, make one like porche or ferrari !

 

There are two types of TPMS. Jaguar uses pressure transducer/transmitters coded to each wheel. If you have TPMS valve stems you have this type. The other type doesn't use sensors in the tires.

My point about an inconsistent system being more dangerous than a non existent system is comparable to the argument about a seatbelt that only operates sometimes. You can certainly argue that sometimes is better than none. However, warning systems aren't like that. A warning system offers no direct protection, ever, whether it works or not.

If the TPMS is so unreliable that it is ignored when it illuminates then it is dangerous. It is also by definition useless if it is ignored. Currently implemented TPMS are routinely ignored.

A TPMS system that doesn't even warn until long after the danger has been created is also both useless and dangerous. Anyone who thinks driving with 10 psi low in any tire is not dangerous should have his or her drivers license suspended. 20% low is the standard (for Jaguar that's about 6psi as I mentioned) and that is also very dangerous. The mentality that suggests that an under inflated tire is still safe if it remains on the rim is ludicrous beyond belief. Yet that is apparently the basis for this absurd standard. Apparently, the effect of such low inflation on vehicle handling is unimportant to regulators. This is consistent with standards applied to obtain a drivers license. The idea that the skills required for driving a car are analogous to driving a horse and cart remains fixed in the minds of the regulators and enforcement officials.

The engineers designed a TPMS mandated by the US and now the EU governments. They were not asked to design a system that worked. Governments are like that.

The story of the boy who cried wolf is illustrative of my points.

 

Trouble is, Most everyone who drives a Jaguar are inept and incapable of driving and looking at the dash information at the same time..we are too stupid to be able to interpolate this TPMS or even more complicated and worse yet, the Engine Temp gauge, should one had been installed..It's totally baffling to us Barely literate yokels.

 

jagular - They weren't told to design it the way you stated. It's way more sensible and complex than that. Doesn't mean you're happy with it, but hey.

 

This is yet another example of total obstinance running amok - the TPMS is not "dangerous." The assertion has been made that it is dangerous because it doesn't warn you "soon enough." That's not dangerous, it just means you have to rely on that old standby method of ACTUALLY CHECKING THE PRESSURE, which is what you're supposed to do anyway. What actually IS dangerous is not having the ability to check, via dipstick, the oil level of the car - If your PCM components fail and the warning light doesn't illuminate then, well, the story can get bleak really fast.

The simple reality is that there are a lot variables that make the argument of a couple psi making a lot of difference pretty suspect. For example, just having your car parked in such a way as to have the sun on one side and not the other can easily result in pressures of 4-6 psi difference one side versus the other - can you see that difference visually? Maybe maybe not, and it also is basically irrelevant because it isn't enough to have a profound affect and it certainly isn't dangerous. No one (at least I hope no one) who is doing normal driving is going to think, "Gee, I'm going to be driving west, so therefore the sun will be on the driver's side, and I better put 3 lbs of extra pressure on the passenger side to counterbalance the effects of the sun"

Having a TPMS system set at much less than a 20% threshold would create an incredible number of false indications. I'm also not sure how the further assertion of "It signals false more often than real" is suportable - where is the data beyond the anecdotal that is so readily dismissed when not convenient?

On the contrary, I would imagine that TPMS has saved a lot of people from catasptrophes either of their own making (stupidity) or through an actual problem with a tire...

I thought it might be interesting to attach a link from TireRack showing how difficult it is to visually identify underinflation - and this picture is from a high profile tire where it would be more likely to be visually apparent.

 

Since I've nver had a TPMS warning, I haven't seen the tire specific display - thanks for sharing how it would be depicted.

In what I think is a very strange set of data, the NHTSA conducted a comprehensive study on TPMS effectiveness that showed a 55% reduction in the likelihood of severe underinflation (strikes me as a pretty "effective" system, then), but that vehicles equipped with tire specific (non psi display) warnings were more likely to have underinflation than those vehicles that just have a generic TPMS warning indicator. Those with psi displays were least likely to have underinflation...

 

Maybe the Jag TPMS engineers should have the Nissan TPMS over for Saki and crumpets.
My wife's Nissan has a nice TPMS display on the dash. 33 34 32 32
The sequence for the tires though are: RF LF RR LR
I had to figure the sequence myself since the sales people and service techies all gave me wrong info.
How hard would it be to have a part of the screen show all 4 tires with matching numbers displayed..

 

As I posted earlier, the above pretty much says it all for me....this system like many others on our cars is a secondary back up, an aid to a personal close up inspection / check, that should be carried out anyway.


Put your trust in these systems totally with no regard for visual checks / inspections at your peril.

 

Yes. Just like you need to inspect each tyre for nails, cuts, bulges etc fairly often.

Though people generally don't

 

Just btw any difference in tire pressure caused by local uneven heating by the sun or any other source is completely irrelevant to this discussion. TPMS is designed to deal with LOW pressure as compared to COLD tire pressure settings. Any local uneven heating disappears as soon as you begin driving, as in after a few hundred feet.

Tire pressure is set cold in the expectation that running temperatures will be much higher: 2-5 psi higher depending on ambient temperatures. The TPMS read tire temperature as well as pressure for this reason. These values could be displayed but as mandated they aren't.

As for the failure of anyone to understand the dangers of a safety system that constantly delivers false warnings and fails to warn until after the hazard to be warned against has already occurred, and may have persisted unwarned for extended periods of time well there's none so blind as those that will not see.

This danger is self evident to anyone with any experience evaluating safety systems, something I've spent over 30 years litigating. It is amazing how ignorant the average person can be about what is safe and what is not.

 

We can agree on amazement.

 

Here is an old man begging the question……..why do some responses have to be personal ?? Each of us are mature people with individual opinions. Nothing else is really acceptable in a civilized society…….is this what is wrong with our country now? I truly enjoy the many bits of information from all of you…..and I hope to have the common sense and intellect to decide on my own who to believe in without insulting anyone ! Thanks

 

let's just agree to disagree and move on!

 

This thread has had posts removed to tidy it up, removing non essential and inflammatory comments.

Please by all means continue the discussion with any reasonable informative comments, but keep it civil.

Thank you

 

Here is a link to the 2012 NHTSA study in TPMS effectiveness in which the conclusion is that TPMS equipped vehicles are 55.6% less likely than non TPMS vehicles (of the same model year range) to have severe tire underinflation.

http://www-nrd.nhtsa.dot.gov/Pubs/811681.pdf

The conclusion is of course that TPMS has been very effective at doing exactly what it was intended to do - reduce the likelihood of vehicles having underinflated tires. You're welcome to draw your own conclusions, obviously.

 

One message board I belong to does not allow personal attacks and those who do are either given a warning or booted outright.
Discussions can get "aggressive", but when it gets to a personal level, the mod(s) "fix" things..

 

I'd like to apologize to anyone I have offended in any way by my remarks. Some of them, though I firmly believe that they were responses to unprovoked personal attacks to begin with, certainly went well beyond what would be considered reasonable. I will, however, continue to point out when opinions are presented as proven facts and when what has been shared is simply wrong. Again my apologies.

 

I'll chip in my two cents. 6 psi low may be easy to spot in large sidewall tires, but the low profile tires I have on the XFS and that I had on my previous 540, basically ALWAYs looked flat to the eye (especially if the front tires are at an angle).

I'd like to know the actual pressures, too, because we just had a cold snap, which caused two of the tires to read low. That's expected, and I can take care of it. Well, a few days later, colder again, and another warning for one of the same tires. So I figured ok, it's running a little low, I'll take care of it when we get home. Then come outside ready to leave and think "Okay, that really DOES look low". So I filled it up on the spot and was reading like 16 psi. If I hadn't just happened to walk by on the passenger side, I would have just assumed it was fine.

So while the current system is better than nothing, because I might not have noticed my passenger rear tire was low, I still think actual numbers would be an improvement.