Originally Posted by aznjeep
..oh.. and FWIW.. if it's not required in your state, it doesn't hurt to turn off TPMS (IMO). Yes, it's considered a safety option, but all the vehicles I've had before the "newer" ones didn't have it, and I did fine. You just build a habit of inspecting your tires more often. I reprogrammed ours to not light up until 15psi (AEV Procal). This would be a "band-aid", and not really fix the issue, but then there's still the Sentry key light. If I could have, I would have opted for a LOT less electronic "safety" equipment, although our MyGig Navi is nice...
Its not a safety feature for YOU as much as it is a liability shield for the manufacturer of the vehicle and tires.
A little history on the TPMS. if you recall the Ford rollover lawsuits and tire recalls, basically Ford Excursions and some explorers rolled after either a blowout or during an evasive maneuver. Ford got sued by victims of families for wrongful death and in the investigation three things were found....
First was that most consumers were not aware of the sequence of events that lead to a blow out. The tire does NOT pop like a ballon when you hit a nail on the road- but rather looses air and when running low at speed overflexes and overheats the cords in the sides then shred the hot (soft) rubber and sidewall fails. This also occurs without a road hazard if the tire is not inflated to proper psi. If over inflated the shredding occurs at the sipes edge (Same concentration of heat issue).
Second the tires recalled were unrated for speed. Prior to 1991 there were basically three ratings - S (or unrated on tire) 118 MPH, H up to 130, or V (over 130), When a tire is rated, a sample tire is run at the correct psi for load and the speed at which an hour of run gets the sidewall temp to exceed the carcass temp by predetermined % is the speed rating. See above paragraph - lowering PSI or increasing weight substantially lowers speed rating and the rating goes out the window with a tire that can shred when ran at 55 for an hour! AND the bigger the tire the more 10% below recommended pressure at load affects the temps.
The final finding was that as drivers we rarely start out big - our progression of cars owned starts small and as we marry have kids etc constantly upgrade in size until one day a land yacht is our driveway. So a driver could have YEARS of driving lower weight and smaller tires and never "had" to check their tires so fail to do it on the big monster. Or more precisley never DID check them (or did so by eyeball) and suffered no catastrophic blowout (or did but assumed it popped like a balloon). And of course when they bought that big ol boat no one ever held their hand and explained to them that unlike that lilttle ol buick regal tradein the big heavy excursion was more dangerous when tires were either NOT checked or only checked visually.
So the cause of the rollovers was - weight, speed and inflation meeting up in the danger zone as a van full of family and gear went flying down the freeway at 90 with 15 lbs in the tire in ignorant bliss of the catastophy on the horizon...
So Ford compensated a few families for their loss, Firestone VOLUNTARILY recalled tires used on vehicles over a set weight/cg height formula, replacing them with higher speed rated tires, and the NTHSA mandated manufacturers install monitors on roll over susceptible vehicles as well as developed a NEW rating system that uses 6 MPH increments so that the engineers could be more precise in their loading and pressure calcs and placards. The manufacturers JUMPED at the monitors - not because the monitor would tell the consumer - but when black box data is retrieved from a fatality it would show the CONSUMER was negligent not the manufacturer (as the argument always goes to they made a faulty vehicle that rolls over too easily). Following this unfold I was sickened by how the media portrayed Ford and Firestone as the culprits in the deaths that led to the changes... and even more so when I heard otherwise smart people advise staying away from Firestone tires with an assumption that they were faulty. Major damage to reputation when they really did the right and good thing!
Keep in mind - NTHSA mandates are for MANUFACTURER. As a consumer you CAN disable the monitor (preset warning points become fairly moot anyway unless the tires installed are EXACT replacements for the OEMs) and states really have not set laws yet regarding disabling or altering (how do you know what the danger point is in a non OEM unless you are an engineer with access to all the data so how can a state mandate what you do with it?) - but keep in mind if you sell it and the new owner ever gets in a tire related fatality - your assets become targets for their lawyer when the black box shows it was disabled or altered!!!
This fiasco was one of the things that drove me out of the customs manufacturing career - it was just getting too crazy with "someone else" must look after me stuff just like this (we got sued over a precise fuel guage - at "empty" it died and the guy was rear ended - his arguement was in every other car when it says empty I still have a ways to go... duh EMPTY MEANS EMPTY YOU MORON!!!!! - we prevailed - but only because we did not come under NHTSA mandates building fewer than 12 of any same model per year so were not required to build a reserve into the display of fuel level).