Green tire valve caps

[HoughMade]

Plinkers...gotta love 'em

 

[JettaKnight]

My apologies to all!! My 20 yrs in welding industry 15 yrs ago has clouded some of my thinking. Yes they do expand & contract to temperature but I was speaking in real world temp ranges..not absolutes as in a lab environment .I didn't feel it was relevant to the discussion . In a tire filled with 100% nitrogen or argon I certainly would only think the pressure change would be almost negligible on a tire gauge. In one with 78% there could be changes because of the other stuff. Yes, I did realize air has nitrogen in it along with other STUFF,( too many to remember all).Again, I took to heart that some bozo was actually marketing a 78% nitrogen product & that there are people buying it. I did not read that part as a spoof! Again.. My apologies .

The real world of tire temperature ranges are enough that TPMS must compensate for the change. The gas inside doesn't expand & contract (much) because the tire constrict the volume. Therefore the pressure must increase. That's why the placard pressure is listed as the cold pressure. If you stop after driving for an hour on the highway and measure, then the pressure will be higher than when you measure before your trip.

 

[rhino]

The real world of tire temperature ranges are enough that TPMS must compensate for the change. The gas inside doesn't expand & contract (much) because the tire constrict the volume. Therefore the pressure must increase. That's why the placard pressure is listed as the cold pressure. If you stop after driving for an hour on the highway and measure, then the pressure will be higher than when you measure before your trip.

Correct!

If in doubt, PV = nRT

n and R are fixed. If V is also fixed, then P must increase as T increases and decrease similarly.

 

[HoughMade]

Correct!

If in doubt, PV = nRT

n and R are fixed. If V is also fixed, then P must increase as T increases and decrease similarly.

One engineer thread is enough....nerd.

 

[rhino]

One engineer thread is enough....nerd.

Oh, how the shoe fits.

 

[dvd1955]

Our Bonneville used to have a reset function - found it in the owners manual. Every time you level off the tire pressure where it belongs, sit the car on level ground with the engine running in park, then there was a dash procedure for resetting it. That system registered differences in the handling of the vehicle to alert you of low tire pressure.

This could very well be her problem. Car is now 3 years old, original tires. Haven't investigated how the monitors work, but since I'm going to her place for a visit Saturday, I'll get her manual out and see if they can be reset. Could it be this has to be done after the tires wear the tread down some?

 

[Double T]

Dihydrogen? I think you mean BIhydrogen oxide.

Probably. Unless he likes using hydric acid on that shiny paint job.