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[Transport3r]

Originally Posted by pits200

Sorry man he is right about nitrogen, they use it in race cars and places like Wal-Mart for an extra cost. It will expand like o2 but will need to be a higher temperature which most street cars could never reach to reach entropy and cause expansion in the tire hence fluctuation of psi when driving.

Sure the pressure change will be less, but only because the nitrogen is also dried. Filling the tire with dry air will yield the same pressure change over temperature. Race teams use nitrogen to ensure the rate of pressure change over temperature is the same for each tire by ensuring the composition of gases in each tire are exactly the same. I don't think that the difference is worth the extra cost on a street car. THe only benefit i can see is that the nitrogen will not permeate through the tire like oxygen does over time. I check my tires weekly anyway, so not worth it to me.

Meh, those pen gauges and even the digital ones are ok...as long as they're consistent that's all that matters, but I've gone from one to another back to back and they've shown a difference of 4 psi lol so I stopped using them altogether.

I've been using this one lately though and love it:
http://www.amazon.com/Joes-Racing-32...rds=tire+gauge

[Wires]

Originally Posted by Transport3r

Sure the pressure change will be less, but only because the nitrogen is also dried. Filling the tire with dry air will yield the same pressure change over temperature. Race teams use nitrogen to ensure the rate of pressure change over temperature is the same for each tire by ensuring the composition of gases in each tire are exactly the same. I don't think that the difference is worth the extra cost on a street car. THe only benefit i can see is that the nitrogen will not permeate through the tire like oxygen does over time. I check my tires weekly anyway, so not worth it to me.

Nitrogen is used in race cars and plane tires for the lack of flamability reasons. It's a waste of money and a marketing scam (like electronics extended warranties). But, to each their own.

Air is 78% nitrogen already.

[gunnerxq]

Originally Posted by nukezero

I had a nail in the tire this weekend and took it to America's Tire to get it fixed for free since I bought my Michelin Super Sports there.

I told them to put 38/40 psi front rear.

Why such high psi? And what tire sizes do you have?

Originally Posted by Wires

Nitrogen is used in race cars and plane tires for the lack of flamability reasons. It's a waste of money and a marketing scam (like electronics extended warranties). But, to each their own.

Air is 78% nitrogen already.

Meh, you could go either way with that argument. As long as the air you're pumping into your tires is properly dried, then you'll get just about the same results as going with nitrogen; but what are the chances that your air compressor at home, etc. has all the filters and water separators necessary to make sure that happens correctly...

Here's a good link explaining it more in detail:
http://tirenitrogen.typepad.com/news...09%20FINAL.pdf

Even though this link points to manufacturers literature, they still do a good job of pointing out some myths and rules of thumb when it comes to PROPERLY using nitrogen and how it compares to regular compressed air.

[Wires]

About the same chance as the tire jockey throwing a vacuum on each tire to ensure there is no air/moisture in it before he refills it with nitrogen.

[rogerdiaz]

Originally Posted by nukezero

I had a nail in the tire this weekend and took it to America's Tire to get it fixed for free since I bought my Michelin Super Sports there.

I told them to put 38/40 psi front rear.

After driving the car for another day, I realized damn, the car feels a bit rock hard for some reason, even on the freeway. Almost worse than run flats. I took it to Santa Monica today with my girlfriend and sure enough with poor roads there, something was off about my tires/car.

Pulled into a gas station for air and bust out my tire gauge. Guess what, my fucken tires are at 50psi rear, 48 psi front left, and 38 psi front right.

I dropped the pressure and now it rides smooth.

Those guys fucked up royally. It's strange because I was watching them through the window as they used an electronic tire pump to put air in it. You set the number digitally and then it pumps air into it until the desired PSI is reached. No mechanical gauge.

To make matters worse, they worked very fast because there was 2 guys working on my car, one on each side with different pumps.

I also compared my tire gauge pen that I got from America's Tire as well as the gas station pump's mechanical gauge. I found that the tire gauge pen was fairly accurate!!

YEAH, OKAY, COOL STORY BRO!

what size wheels you running? you on runflats? going to see if your 38/40 will do good on my 19s.

[chromisdesigns]

Originally Posted by gunnerxq

Why such high psi? And what tire sizes do you have?

I've run 38/40 with my Michelin Pilot Sport A/S+ since I got them. I found the stock pressures (designed for runflats) to be too low with conventional tires. I always ran 38 all around on Pilot Super Sports with my old M3.

I've believed for a long time that stock E90 pressures were intended to help ameliorate the horrible ride from the OEM runflats. You might take note that people who track their cars pretty much ALWAYS run higher pressues with the runflats, if they still have them at all.

[Wires]

Originally Posted by chromisdesigns

I've run 38/40 with my Michelin Pilot Sport A/S+ since I got them. I found the stock pressures (designed for runflats) to be too low with conventional tires. I always ran 38 all around on Pilot Super Sports with my old M3.

I've believed for a long time that stock E90 pressures were intended to help ameliorate the horrible ride from the OEM runflats. You might take note that people who track their cars pretty much ALWAYS run higher pressues with the runflats, if they still have them at all.

If you contact Michelin, they'll be able to give you the recommended pressure for those tires on your car.

I did that once with some oversized tires I put on my truck.