jaapv said:
In case of a slow leak, the warning will come on before you have a blowout. Sudden catastrophic blowouts that cause loss of control will normally happen if one should drive over something sharp at speeds (far) over the legal limit. TPMS won't help you in that case. The warning light system is all that is needed for safety.
Besides, TPMS only arrived in 2014. Before that I cannot recall any newspaper report of a highway death by that cause. Of course, some may have gone unreported and I don't read all newspapers
. All in all I think the possibility is rather remote.
Having TPMS report your tyre pressure, which I have by the Steelmate DIY system (recommended!), is for convenience. One does not need to waste time by checking tyre pressures every few weeks.
You've never heard of the Ford/Firestone controversy? https://en.wikipedia.org/wiki/Firestone_and_Ford_tire_controversy I believe this was what led to the Ford Explorer being mockingly called the "Ford Exploder" and it resulted in over 200 deaths when tires blew out. This is also the incident that directly led to the passage of the TREAD Act which is why TPMS was required in the US from 2014 onwards.
You are incorrect that I'd always get a warning light before the tires blow out. Tire wear is sort of like the way mechanical stress fractures work on aircraft parts; small microscopic cracks caused by severe operating conditions get bigger and bigger, until eventually, the whole thing fails. Operating a tire even 5 psi below its recommended pressure will result in increased amounts of heat, which results in increased amounts of thermal oxidative degradation http://polymerdatabase.com/polymer%20chemistry/Thermal%20Degradation%20Elastomers.html and the effect is cumulative.
In some ways though, tire blowouts are also like the well known fire triangle https://en.wikipedia.org/wiki/Fire_triangle in which oxygen, heat, and fuel must all be present for a fire to burn. Tire blowouts generally require high ambient temperatures, high speeds, and underinflation in order to cause total failure of a tire sidewall (there's also a fourth factor that comes into play as well: long drive duration). Now weather is obviously something we can't control, drive duration is dictated by where we have to go, and speeds are generally dictated by prevailing flow of traffic. The one thing that we can control most easily is the inflation pressure of our tires. So while it's probably perfectly safe to do drive I-5 between San Francisco and Los Angeles in the wintertime, even with the tires severely underinflated, and it's perfectly safe to drive in a traffic jam during rush hour in Phoenix, Arizona in July, if you were to drive hundreds of miles on rural I-5 between San Francisco and Los Angeles in July when it's 40°C out, you lose all of that safety margin. If I drive a vehicle in such conditions I obviously check the pressures before even starting, but if I had an option to do so, I'd keep the instrument cluster display always set to display the individual pressures, so that if there was a slight leak that developed on that trip (say I run over a nail), I'd see it immediately and can pull over and address the problem. But what Mitsu has done with this system is they have removed a key safety feature that could prevent all of those factors that can cause tire failure from being present simultaneously, and it can have catastrophic consequences, especially on an SUV which, like the Ford Explorer, is far more likely to roll over if a blowout does occur. I mean, what do you want me to do, pull over and stop on the shoulder of the freeway every 10 minutes to check pressures when it's 40°C outside? And the thing is, the amount of cost to just have the computer display information it already has is so low, and the safety margin I would gain from being able to see it is so high, that's why I'm angry at them.
greendwarf said:
As I suggested earlier, the US market apparently expects individual tyre pressure readings whereas in the EU it looks as though the legal requirement has arisen out of a desire to meet the minimum US threshold to support exports, rather than be driven by safety concerns here (so jaapv is sort of correct, lol.) Japan would have followed this to export to Europe.
So STS134 is right that there has been a reluctance by non-US manufacturers to do more than the minimum needed to sell, especially as North America is not their core market (unlike Europe). US manufacturers can't risk doing that. This is just the way business works.
If you insist on buying a foreign import then inevitably you have to accept that it won't be designed in the same way as a domestic product. You have to trade off novelty(?) against lack of "normal" features. As North America is always going to be only a niche market for a small manufacturer like Mitsu. I'm afraid STS134 will just have to grin and bear it. :lol:
I really don't see what this has to do with US vs. Europe vs. Japan, as there are both European and Japanese models that do have individual pressures displayed in the TPMS. Nissan, Porsche, etc.
Sumpy said:
STS134, I was agreeing with your point that the car could/should provide extra information, (I would like to see coolant temps and engine revs as well), but I'm afraid you have lost credibility with me in this discussion when you bring up the Boing Boing 737 latest problem and cover up, Mitsubishi have not covered up a known problem with the TPMS, they have simply adhered to standard legal requirements.
I am aware that they haven't covered up a problem. But my point is, that had Boeing given the pilots information that the AoA sensor information was not in agreement, they may have been able to figure out what the issue was, before the planes plowed into the ground or the ocean. Or had they simply had a "MCAS Active" light that tells you what is pushing the nose down, and had an entry in the flight manual for MCAS. The point is, the computer was doing something to override pilot input, and they weren't giving any information about what it was doing and why. And they did it allegedly because they feared overwhelming the pilots, which is very similar to some of the arguments I heard around here that people would be too stupid to interpret pressures correctly (they didn't want to have to retrain pilots to learn what the new systems did, the same way some might argue that Mitsu didn't want to retrain drivers to understand what happens to tire pressures when you drive a car and the tires heat up).
