official TPMS info from Toyota tech training class

Doc, any updates on the tC sensors, and any part numbers? Maybe I need to head down to my Toyota dealer's parts counter too, before I buy a set of takeoff tC wheels...

 

Hello Everyone!

For those who don't like the idea of spending US $300 to $600 for a digital TPMS (or about half that for extra sensors for Winter Tires), but are genuinely concerned about the status of their tires (that IS why you're reading this), consider Tire Minders from Minder Research, Inc. (Hobbit, are you paying attention?)

I use a set of Tire Minder Max on my 1992 Toyota Prius and obtain excellent results. (I bought them at Pep Boys.) The various Tire Minder web pages are:

Tire Minder Original at http://www.minderresearch.com/tireminder.html
This original series includes a model that will work for Prii with the pressure set at either 40 or 42 PSIG. This is especially attractive as a solution for those who use snow tires on a vehicle with the factory installed (user-unfriendly) TPMS.

Tire Minder Max at http://www.minderresearch.com/tiremax.html
This heavy duty 3-model series covers the vast majority of current passenger vehicles. It does NOT include a model that will work for Prii, unless you are using Toyota's factory recommended pressure (but why would you?). It happens to include a model that is ideal for my 92 Previa. These are available at Pep Boys, among other places.

High Pressure Tire Minder Max at http://www.minderresearch.com/tirehighpressure.html
This heavy duty series includes a model suited for the Stupid Spare Tire that typically requires 60 PSIG.

Certain models might be hard to find. Look here for help finding them: http://www.minderresearch.com/wheretobuy.html

Minder Research suggests replacing the monitors every 18 months. I find they last longer than that. They do have two common failure modes. They either get stuck or they start leaking. There is a very small hole in the end of the minder; it has to be there for proper operation. Eventually road salt will find it's way into the hole, and from there it will reach the cylinder and piston that moves the colored flag. They will corrode causing it to stick or leak. If it fails by leaking it will correctly show the leak and any tire shop can reveal it by dunking the wheel. Minder Research recommends you remove and reinstall the Minders once every two months; if you do this you'll spot stuck Minders before they cause grief.

My real life experience with the Previa is that natural (totally normal) tire leakage makes it necessary to add air several times a year anyway, so there is no need to obsess about stuck Minders. When one fails you'll have to buy a set of 4 anyway, so always replace all of them if any fail.

I also used another brand, which I won't name because I no longer recommend them. They were also accurate, and had the same failure modes described above. They also lasted several years. However, their bodies were made of aluminum. The dissimilar metals of brass valve stems with aluminum bodies eventually caused corrosion. One corroded badly enough that I had to use Vise Grips to get it off the stem. The stem cleaned up nicely and did not need to be replaced. (If the Minder Research product had not been available, I would have bought another set of aluminum devices rather than go without any sort of monitor.)

The Tire Minders appear to be made of brass with either a nickel or chrome plating. Either way, I do NOT expect to see this corrode. However it must be noted, I have not owned these Tire Minders long enough to know from personal experience.

Even if you replace Tire Minders every 12 months, they are still substantially less expensive than even the cheapest digital TPMS. (Don't forget: digital TPMS transmitters have to be replaced every 5 years due to dead batteries.)

 

Errrrrr, my main goal is to get new rims *and* to not have to stare at the TPMS idiot light being falsely lit. I don't think Tire Minders or whatever would help one bit.

What's a 1992 Prius, anyway?

 

There's been several comments on the 25% drop being a larger value than desirable.

Why couldn't you simply overinflate, reset the system, then reduce the pressure to the desired value?

For example: For a 42 psi running pressure, overinflate the tire (only for a minute or two) to 51 psi, reset the system, then let air out to 42 psi. The system will warn you of a 25% drop from 51, which means a warning at about 38, which is effectively only 10% below 42.

 

1992 Prius???????
Doh!
Of course I meant 1992 "Previa" van.
Spelling checkers aren't *any* help at all when you spell the wrong word correctly...

 

<div class='quotetop'>QUOTE(M. Oiseau @ Apr 5 2006, 11:18 AM) [snapback]235295[/snapback]</div>

Has anyone already tried this?

 

<div class='quotetop'>QUOTE(M. Oiseau @ Apr 10 2006, 02:32 PM) [snapback]237635[/snapback]</div>

Hello Everyone!

It all sounds like a really good idea, *except* inflating beyond the "Max. Cold inflation Pressure" molded into the sidewall of the tire might be unwise. As a former taxicab driver I've logged several million miles, and have never deliberately over-inflated a tire beyond the "max" number. I have done so accidentally a couple of times, but don't recall anything horrible happening as a result.

Temporary deliberate overinflation, driving slowly and only as far as necessary to trigger the TPMS transmitters, might be OK. I'm really not sure, so I'm going to do some research on the topic (uh, *after* I finish my US Federal taxes... I owe so I waited till the end!)

BTW: My SmarTire TPMS & HydroEdge tires are both still making me a very happy camper!

Brad

 

I once again sort of lost track of this thread, but finally found
Brad's excellent rundown on the SmartTire. I knew about that system
from various searches a while ago -- the big-hose-clamp mounting
system seems a little weird, but I guess it makes sense especially
from the standpoint of keeping the TPMS transmitter as close to the
center of the wheel as possible [and the convenient weight-balance
of the worm fitting, heh]. Good stuff.
.
I have also been doing a little experimenting with differential
speed analysis. Actually that's too fancy and overblown a manner
of stating it. What I'm doing is reading *beat* frequencies between
adjacent pairs of wheel-speed sensors and simply displaying them,
leaving the "analysis" part to my own brain. I wrote this up in
greater depth over on Prius_Technical_Stuff, and so far it has only
reached quick-n-dirty hack status on a breadboard tossed into the
passenger footwell. But early results are fairly promising --
there's definitely a notable speed delta as a tire starts going
soft. With about 44/42 as the benchmark, I start seeing results
when a tire gets down around 35 psi. I took one as low as 25
yesterday, and that yields a fairly high "blink rate".
.
There will doubtless be a webpage all about this at some point, but
it's basically still on the bench and not even monitoring all 4
inputs so I can't make any firm statements yet. But at least I
think I can stop worrying about curb feelers -- the vertical distance
threshold I'd expect to detect with those is about the same as the
pressure difference that causes visible speed-sensor deltas.
.
And yes, I'm quite aware that indirect systems in general have NOT
been acceptable to the NHTSA / TREAD evaluations and they're only
advocating direct measurements systems now. Someday for me, maybe,
but right now I'm having fun with this.
.
_H*

 

As of yesterday the Prius pressure sensors are not in the system...

Just keep waiting.