Tire Pressure Problems

[Matster]

Anyone else having problems keeping their tire pressure at 36psi/248kpa? Since June I have had to top the tire pressure up every couple of weeks. Check them while cold, top them up to 36 psi and within a week or so the monitor on the DIC says they are now down ever so slightly (2lbs on one tire, 3lbs on another, etc.), not all are and it is never the same tire(s) that are below the 36 psi.

Has anyone had nitrogen added to their tire air and does it really help? This is more an annoyance than anything else, but with the price of the P-Zero's being what they are, any unnecessary wear is costing money.

[camaro99]

yes . I kept getting ON STAR emails in june and aug that the pressure was ok eventhough it was anywhere from 224 to 242. Then when I went to the dealer two months after buying the car they said there was only 30lbs in each tire so they filled it up to 36. Then last week , ONSTAR again shows less than 248 (238-244) but again gives the green checkmark as if its ok. Left rear is lowest with 238 right now.
Guess nitrogen is the key.

[Matster]

Originally Posted by camaro99

yes . I kept getting ON STAR emails in june and aug that the pressure was ok eventhough it was anywhere from 224 to 242. Then when I went to the dealer two months after buying the car they said there was only 30lbs in each tire so they filled it up to 36. Then last week , ONSTAR again shows less than 248 (238-244) but again gives the green checkmark as if its ok. Left rear is lowest with 238 right now.
Guess nitrogen is the key.

Glad to see I am not the only one with this issue, my OnStar e-mail came in last thursday the 24th, stating tire pressure was OK but the readings it showed were .....Left Front:240 kPa Right Front:236 kPa Left Rear:248 kPa Right Rear:244 kPa

This after I had just checked and filled each to the recommended 248kpa on Sunday the 20th.

[Cyber_Gray_Autobot]

There was a thread about this somewhere on the forum where one of the sensors was not working correctly. The conclusion from that thread was that a manual check (with another gauge) was probably the best indicator of air pressure.

Air is already made up of mostly Nitrogen (about 70%). I have heard that Nitrogen in tires does not make that much of a difference.

[HeavyD]

No tire will ever be 100% air-tight. Every tire will leak about 2 psi a month. Air molecules will actually percolate through the rubber. Some will leak faster, others slower. When you start to lose 5 psi in a couple of weeks, then you have a problem.

[SQUALO]

I was having the same issue, but I was monitoring them on a weekly basis. When I checked them, with my own tire pressure gauge, it was giving a proper inflated reading. I noticed that when I checked the pressure reading, through the car, the metric reading was indicating they were low. However, when I would set the reading to imperial, it would show that the tires were 2 pounds over the inflation rate
I just trust my own tire pressure gauge, and not a computer, because I also got those on-star monthly reports indicating the opposite. I know of other people, who bought cars in the past with tire sensor readers, and they too indicated false readings.

MY ADVICE IS ALWAYS HAVE A HIGH QUALITY TIRE PRESSURE GAUGE WITH YOU! PLEASE DON'T USE THOSE $5 POP-UP STICK GAUGES, INVEST IN A GOOD ONE PREFERRABLY THE DIAL TYPE, EVEN THE DIGITAL CAN GIVE FALSE READINGS.

[canadian ss]

When using conventional air, the readings will always jump a few psi. If one side of your car is warmed up by the sun more compared to the other, naturally the air pressure on the warm side will go up.
If using nitrogen, this problem shouldn't really occur because there is no moisture in the element to fluctuate with sun or hot cold inflation issues. Search the use of nitrogen in tires and it will explain it better than I could this morning.

[bumblebee rules]

Has anyone used nitrogen yet ??? Our tire shop just got the compressor installed and wants me to do it ??? Not sure, what does everyone think ?? :-)

[bluch]

i haven't had any problems with this. haven't touched my tire pressures since i got her. that was back in July...

[FNKNSTN]

I don't know why shops are pushing Nitrogen inflation. The air you breathe is mostly Nitrogen. And how do I check if there really IS 100% Nitrogen in my tires?

I've noticed the slow leak. Make sure the air valves are tight.

[FNKNSTN]

Originally Posted by canadian ss

When using conventional air, the readings will always jump a few psi. If one side of your car is warmed up by the sun more compared to the other, naturally the air pressure on the warm side will go up.
If using nitrogen, this problem shouldn't really occur because there is no moisture in the element to fluctuate with sun or hot cold inflation issues. Search the use of nitrogen in tires and it will explain it better than I could this morning.

The pressure will fluctuate with heat REGARDLESS of "moisture" content.

Hot gases expand and create high pressure within an enclosure.

Cooled gasses will compress and create low pressure within an enclosure.

Check your pressure on a cool morning.

Fill your tires to 36psi.

Ensure that the valves are tight.

[CanadianCamaro]

I think RickRay has Nitrogen. I haven't noticed any loss parse. But I check regularly and adjust as necessary. Try to do while car is cool and in the garage as running temps, direct sunlight etc affects the pressures and results in uneven inflation. Dito on the high quality gauge. Don't forget that pressures will change as the season changes too. As it gets colder you'll need to add more air to maintain proper pressure.

On a side note, I wonder what will happen to the silly monthy OnStar emails when I store her for the winter and disconnect the battery ground strap? (sorry for the jacked thread)

[HeavyD]

Man, this nitrogen has got to be the biggest gimic! Unless you are driving a NASCAR at 200 mph, you don't need nitrogen. Your tires aren't going to expand enough due to heat to make using nitrogen worth it. I do work in a dealership, for heavy trucks. We had a large fleet that used nitrogen on a bunch of test trucks and trailers and saw no difference in tire life or pressure retainabilty. Due to the added hassle and cost of needing special compressors, or nitrogen bottles, they canceled it. Don't waste your money!

[LIV42DAY]

With colder weather coming pressure flucuation will happen almost daily. for every 10 degree drop in temp you will lose a 1 lb of air. nitrogen is over rated anyways it still loses pressure just at much slower rate.