[Fformula88]

I am not up on all of the latest laws, but didn't the government mandate that new cars will soon need to have onboard tire air pressure monitors?

If so, the Solstice will need such a system. Would this work through the DIC on the dash?

 

[2KWK4U]

Not if the DIC is an option. I'm betting we all see a new dummy light if once the law gets phased in (seems I've heard of it, too).

 

[rlhammon]

I am not up on all of the latest laws, but didn't the government mandate that new cars will soon need to have onboard tire air pressure monitors?

If so, the Solstice will need such a system. Would this work through the DIC on the dash?

I seem to remember this as well, so I looked it up.

http://www.nhtsa.dot.gov/cars/rules/rulings/TPMS_FMVSS_No138/

More there than you'd want to read unless you make these systems, but I didn't see anything that stated an implementation date. Also, FMVSS #138 does not appear in the current release of regulations, so it's not active at this point and will not be required on 2006 model year cars.

 

[Fformula88]

I seem to remember this as well, so I looked it up.

http://www.nhtsa.dot.gov/cars/rules/rulings/TPMS_FMVSS_No138/

More there than you'd want to read unless you make these systems, but I didn't see anything that stated an implementation date. Also, FMVSS #138 does not appear in the current release of regulations, so it's not active at this point and will not be required on 2006 model year cars.

Thanks for doing the research on it! Then I guess we are not likely to see such a system.

 

[SolsticeMan]

Unless they put run-flats on the car.

I don't think there's a government requirement for it, but pretty sure most of the manufacturers (honda, BMW, GM) that use run-flats on their cars incorporate some sort of tire pressure monitor.

Not sure why, but suspect it has to do with the qualities of a run-flat at less than specified pressure. I drove a friend's 'Vette one time (a C5) and the tire pressure indicator identified the LF tire, kept saying ony 16 PSI in that tire... but the car drove fine. When we got back to his house, sho' 'nuff, 16 PSI in the LF. Got me wondering how you'd tell if the tire was almost flat without the monitor - how low would you have to go to be OBVIOUS to the driver that you had a flat?

Those mothers are HEAVY, BTW (Corvette run-flats). Hopefully the Solstice doesn't decide to slap them on. At least we know the first year doesn't have them, so I suppose it's unlikely they will have tire pressure monitoring on this "back to basics" roadster.

 

[rlhammon]

Yeah, with run flat tires all OEM's seem (I can't think of one that doesn't I guess I should say) to have a tire pressure monitor. Currently it's only a recommendation and most companies have implemented some sort of system on some of their cars.

I had a montior (just a light on the dash, no indication which tire) on my last car it was rather handy the few times it actually lighted up.

 

[slowandlow]

i have one on my alero sort of it mesures the amount differance between the tires rotation and if one is different from the other it goes off it is very stupid and gives false 99.9% of the time.

 

[rlhammon]

i have one on my alero sort of it mesures the amount differance between the tires rotation and if one is different from the other it goes off it is very stupid and gives false 99.9% of the time.

The car I happened to be referring to in my last post was my Olds Alero. I never saw it give a false reading. I found that it was set for a 10% differential, and it looks at average rotational speed. So... many people who don't pay attention to the tire pressure will have tires around 30 psi, and when one hits 26 - 27 the light goes off. If you get out and look, you don't notice anything... but if you take a gauge to the tires, you'll see the light was correct.

If your having problems with your light going off all the time, and you put a gauge to your tires and think the light is wrong... check your wheel bearings. The N-bodies have known problems with wheel bearings which have caused problems and subsequently sets off the lights.

 

[slowandlow]

it is not all the time but usaly it is wrong. it usaly goes off in the freeway in a long turn

 

[dls6774]

Autoline Detroit just did a segment with a guy whose company develops the tools the dealerships use to diagnose and service vehicles. He was saying that they were developing (had developed?) a tool so that when tire pressure monitored tires were rotated the mechanic would be able to set the system so it would know where the sensors were after the rotation. Are the systems more complex now or has it always worked that way?

I've never had a vehicle with tire pressure monitoring so this is all new to me.

So if I rotate my own tires, I'll just have to remember that that low pressure light I'm getting for the left front tire is really the left rear tire? Or buy the tool to reset the sensors myself? Or take it back to the dealer and for a nominal charge they'll reset them? Interesting...

 

[rlhammon]

Autoline Detroit just did a segment with a guy whose company develops the tools the dealerships use to diagnose and service vehicles. He was saying that they were developing (had developed?) a tool so that when tire pressure monitored tires were rotated the mechanic would be able to set the system so it would know where the sensors were after the rotation. Are the systems more complex now or has it always worked that way?

I've never had a vehicle with tire pressure monitoring so this is all new to me.

So if I rotate my own tires, I'll just have to remember that that low pressure light I'm getting for the left front tire is really the left rear tire? Or buy the tool to reset the sensors myself? Or take it back to the dealer and for a nominal charge they'll reset them? Interesting...

This makes NO sense to me at all. The sensor is not inside the tire, at least not on any system I've seen recently. That makes no sense at all from an engineering stand point either.

Usually they detect rotational speed of the wheel (many use the ABS system) and look at a difference between one tire to the others (maybe an average, I'm not sure), and detect a tire is low in comparision. The systems which tell you which tire simply add more logic into the controller to keep track of the tires independently.

No good usable system would be tied to the tire, because people change tires all the time and then the system is gone. How do you make a connection between the tire and the car in the sort of system you are takling about?

I'm not trying to rip you apart on this... instead I think there was a misunderstanding... or someone is making one wierd system, I'm not always correct, I know that.

 

[SolsticeMan]

This makes NO sense to me at all. The sensor is not inside the tire, at least not on any system I've seen recently. That makes no sense at all from an engineering stand point either.
....

Actually, this is exactly the case for the Corvette, and the XLR. Each wheel has a sensor/transmitter on the valve stem inside the wheel that transmits the tire pressure to a receiver in the car. Each wheel and tire is specific, esp. for directional wheel patterns (and asymmetric tread and tire directional rotation, plus the F&R different sizes...), and each transmitter has a different frequency.

You really can't rotate tires on a 'Vette, so keeping track of the wheel is no big deal - the Left Front is the Left Front and would be backwards if you put it on the right.

I believe the Z4 uses similar technology - it's very accurate but also very expensive. I don't know if there is a battery involved with each of the valve stems - I assume so, but never considered it. I just know I've held the transmitter in my hand and looked at the engineer with an incredulous look when he explained what it did...

I think this is one of the issues regarding the new regulations the Gov't is trying to enact - forced tire pressure monitoring. Do you make all the folks buy a super accurate and very expensive system, or do you allow something like wheel-speed sensing (much less accurate but much more affordable - esp. as an add-on software-only function overlaid on top of ABS).

 

[AztekzRpurty]

I have the low tire warning on my Aztek. I would assume it will be the same as the one on the Solstice, if offered. It alerts through the DIC, and does not say which tire. It only false alarms after tire changes, or after you adjust the air pressure in the tires. All you have to do is hit one button to reset. It has been helpful on several occasions.

I had wondered how it worked, I knew there was no way for a sensor in the tire/wheel to be connected, so I thought maybe there was some feedback from the shocks. The abs feedback makes much more sense.

 

[SolsticeMan]

I have the low tire warning on my Aztek. I would assume it will be the same as the one on the Solstice, if offered. It alerts through the DIC, and does not say which tire. It only false alarms after tire changes, or after you adjust the air pressure in the tires. All you have to do is hit one button to reset. It has been helpful on several occasions.

I had wondered how it worked, I knew there was no way for a sensor in the tire/wheel to be connected, so I thought maybe there was some feedback from the shocks. The abs feedback makes much more sense.

Your Az uses the wheel speed sensors from the ABS. I'm 90% sure of it.

Most cars with run-flats OEM must rely on the transmitter-type, because of accuracy and the fact that run-flat properties don't change as drastically with a 15PSI pressure loss when compared to a typical, non-run-flat tire.

 

[dls6774]

Your Az uses the wheel speed sensors from the ABS. I'm 90% sure of it.

Most cars with run-flats OEM must rely on the transmitter-type, because of accuracy and the fact that run-flat properties don't change as drastically with a 15PSI pressure loss when compared to a typical, non-run-flat tire.

Okay... This might be starting to make sense to me... I've seen pictures of valve stems with little black boxes on the inside ends. They'd need to each transmit pressure on a seperate frequency and the receiver would know by the frequency which tire it was. Then if the tires got rotated (for those that can be), the receiver would have to be 'set' to the new location for each frequency. Interesting.

 

[jimmyo]

If the valve cap is assigned to each particular wheel, why can't you just swap out the caps when you rotate tires. Keep the right front on the right front for example?
:crazy:

 

[waiting]

surely the sending unit is in the valve STEM not the cap. Otherwise it would risk leaking and be really expensive to replace when you leave it on top of the compressor when airing your tires.

 

[rlhammon]

Actually, this is exactly the case for the Corvette, and the XLR. Each wheel has a sensor/transmitter on the valve stem inside the wheel that transmits the tire pressure to a receiver in the car. Each wheel and tire is specific, esp. for directional wheel patterns (and asymmetric tread and tire directional rotation, plus the F&R different sizes...), and each transmitter has a different frequency.

Once again it's confirmed I don't know everything!! Thanks for that tidbit Solsticeman. For something along the lines of the Vette, XLR, etc... a car which you can't rotate the tires, that does make sense. On a car such as the Solstice, where you'll want to rotate tires (if you happen to slip the clutch by mistake and light the rear ones up now and then... but I'm sure none of us will do that) it certainly doesn't make sense. Especially on a low cost car...

I'll have to poke around the Vette a bit more, as I've never been interested in the tire pressure system on them. Cool info... I've learned my something new for today!