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hawkman77

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What is the optimum PSI for highway travel? I am using Eagle LS tires. I have used about 33 PSI and gotten 25 mpg, and this last trip there was 30 PSI in them and I got 22 mpg (but that was through the mountains.) Thanks for the input.

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"Optimum" will vary depending on whether you want comfort or mileage. Generally higher pressure = better mileage and lower pressure = softer ride. Each is a trade off for the other.

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I've tried everything from 30psi cold to 35psi cold.

On a hot day, my 30psi in the morning heats up to 35psi in the hot sun, highway driving.

This to me is the perfect balance between ride and handling ... I don't drive enough to care about mpg.

When I tried 35psi cold, on a hot highway drive, my tires heat up to 39psi, setting off the tire pressure monitor warning.

I was surprised to see that tires can jump 4-5 psi as the temp increases.

1989 FWD Fleetwood, Silver

1995 STS Crimson Pearl on Black leather

1997 STS Diamond White

1999 STS Crimson Pearl

2001 STS Silver

2003 STS, Crimson Pearl

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Does Nitrogen expand less than air when heated?, Costco uses Nitrogen

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no nitrogen does not heat up like air does nor does it leak out of your tires like air. you MAY see a 1-2 psi change in your tire depends on how they fill it. Costco uses auto inflators witch do purge to get all air out. works pretty good and free with an oil change cant beat that Unless you work there :D

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I use Nitrogen in my Corvette and love it - stable in all temp's and holds pressure well. Bought my tires at Costco and got free lifetime Nitrogen fills.

Scott

1996 El Dorado

2006 STS

2000 Corvette

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Almost....it's not that Nitrogen is more stable for pressures, expands less, etc. Remember the Gas Laws in High School (or, hopefully by College freshman chemistry)?

PV=NRT

Regardless of the gas. According to this equation, the temperature - pressure curves for O2 and N2 are identical. Or for that matter, for H2, He, Ar, etc, etc.

What is at issue here is MOISTURE. Get rid of the moisture and the pressure differences are less. For passenger cars, filling your tires with Nitrogen is worthless unless you purge ALL the MOISTURE out of the tires first. To not purge the air out of the tire first before filling with N2 is a waste of time and money.

As for even wear or longer lasting tires, I use plain old air and rotate every 10,000 miles and keep them pumped up to 41 PSI COLD (exc my STS which I keep to 35). I *always* get 100,000+ miles out of each set even when the tires are rated for 60,000 miles.

The tires are engineered for use with plain old air for crying out loud.

Using dry air would perform the exact same function as N2 in passenger cars. Some people use air dryers on their air compressors. Not necessarily cheaper, though.

Why N2? It's the cheapest source of a dry gas.

Guys, it's all about maintenance, not snake oil. I think someone decided that since some airplanes use N2 for the tires, it must be a good idea. Airplanes use N2 for tires for many different reasons.

Nitrogen: the new Marvel Mystery Oil

2003 Seville STS 43k miles with the Bose Sound, Navigation System, HID Headlamps, and MagneRide

1993 DeVille. Looks great inside and out! 298k miles!

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I use plain old air and rotate every 10,000 miles and keep them pumped up to 41 PSI COLD

:o Holy sore butt Batman. That must be one stiff ride.

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LOL. Nope. I really can't tell that much of a difference in the ride. If anything, it *improves* it.

2003 Seville STS 43k miles with the Bose Sound, Navigation System, HID Headlamps, and MagneRide

1993 DeVille. Looks great inside and out! 298k miles!

IPB Image

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