Re: tire pressure sensors

I have changed out rims, tires, etc. and no longer have the

> sensors...

Sorry, can't help.

But I wonder why an alternate method of sensing tire under-inflation wasn't used, such as comparing each wheel's RPM using feedback from the ABS sensors. A tire with significantly lower air pressure than the other 3 would register a higher RMP compared to the other 3, and this would serve as useful warning to check the tire. No sensors inside the wheel is needed - infact no additional parts needed (just a few extra lines of software code in the car's computer).

Reply to
MoPar Man
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Because this is more complicated than it seems. For starters unless the air pressure is really low, the RPM difference isn't as much as you think. Second, during a turn, the outside tires turn at a higher RPM. SO now the car computer needs to know when the vehicle is turning and then ignore the rpm difference during a turn. So then what do you do if a tire picks up a nail on one of those windy roads that the car commercials all seem to think that are the cat's meow to drive on?

Ted

Reply to
Ted Mittelstaedt

The DOT regulations do allow this alternative method. The Federal Court of Appeals has just thrown out that portion that allowed the ABS sensor method because it was irrational. 1. It would not detect the fact that all 4 tires were significantly underinflated. 2. It had a very high failure rate at detecting in a timely manner the situation when just one tire was underinflated. The regulation reflects the impact of special interest money on our regulatory system and not a regulatory system working in the public interest.

Richard.

Reply to
Richard

Good questions: 1. The federal government mandated the inclusion of tire pressure sensors. 2. Although judged less effective, anti-lock related sensors were authorized for the first few years of the requirement because the industry pressured for this method because it was significantly less expensive to implement. 3. Safety groups challenged this regulation in Federal Court because it argued that only individual pressure sensors worked. 4. The Court judged the phase-in part of the regulation that permitted anti-lock related sensors invalid because it was irrational because the data used to set the regulation proved that such sensors were not reliable enough to meet the requirements of the regulation.

Richard.

Reply to
Richard

"Richard" wrote in message news:

Reply to
Ted Mittelstaedt

Ted Mittelstaedt spewed:

Why is Richard supposed to listen to you?

1) I put forward a logical argument backed up by a little math as to why RPM counting should be able to detect tire pressure imbalances. I know it was employed by at least one car maker in a rental car I drove a few years ago (I think it was GM). 2) You in your wisdom haven't even tried to counter that argument on technical or theoretical grounds. 3) Richard has claimed that court documents presented by special interests show that RPM counting doesn't work, but gives no details of the tests performed, the results, or how the conculsions were reached. (One would think that special interest groups interested in automotive safety would have bigger fish to fry than low-tire-pressure-sensing using RPM counting. If that was such a hot-button topic for them they why not mandate the use of run-flat or self-sealing tires, or outlaw the use of aluminum rims that are prone to leaks which lead to low tire pressure). 4) This thread was at an end with Richard's last response until you butted your nose in with your post that added nothing to the thread (Richard had responded, I posted no further rebuttle, but you just had to stick your nose in and tell him not to respond. What was the point of that?). IF you don't like this thread (or my posts) then you don't have to read them. Your post was nothing more than a transparent attempt to marginalize me by telling people not to carry out a dialog with me. Does this make you feel important, or wise, or intelligent? I've got news for you. You're none of the above.
Reply to
MoPar Man

My wife's 2000 Buick has this feature which uses the ABS sensors etc. I don't think it has ever indicated a true low tire. But it has given some false indications and I think it has to be "reset" after tire rotation

Reply to
Rudy Allemann

Calm down guys. As a regulatory attorney of sorts I am interested in regulatory actions like this. I have not reviewed the technical file before the court (it would be an interesting read). I have merely tried to convey the standard used by the court in rejecting that portion of the regulation. This is not the place to discuss the merits of the Court's decision (although that too would be an interesting discussion). In the end the Court agreed with the petitioners that the agency's action was not supported by the data and was therefore irrational.

Richard.

Reply to
Richard

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