Nitrogen fills for tires are in the same class as dealer rustproofing, dealer Miracle Shield never wax again treatment, $200 tape-on pin stripes, $400 theft deterrent systems(etched numbers on windows) and "documentation" fees. Not for me.

 

Be aware of your tire temperature when you inflate them. Normally you check and set your pressure when the tires are cold. If your gas station is more than about a mile away, driving friction will have warmed up your tires by the time you reach the gas station. When fully warmed up, the pressure is probably about 2-3 psi higher than when they are cold.

 

Welcome to the club (reduced MPG in cold temps)Mine is the same way.

But along with a lil bit of reduced PSI in the tires, i have put up with one , and a second tire to a lesser extent, losing pressure (25 from 32psi) over the course of 3-4 days. My first vehicle with TPI, and good thing cuz it's hard to see a bulge from a low tire with our skinny sidewall tires for sure.
I'll prob remove the offending tires and take them in to a local ,decent tire place to have them check it out.(ain't no way i'm gonna let even the dealership mash the lugs back on if i took the car in ,and prob only to send them down the road to a tire place anyway.)
I've had trouble with a few Michelin tires in the recent past with not sealing well to a rim (3-4 trips and then they gooped up the rim to seal things, that finally worked) so i imagine in my case it might be the same problem, sealing at the rim.

 

Luckily my gas station is only a few hundred yards away. The dealership isn't even a mile. Our apartment is in a weird spot. it's really nice and we get no road noise, and we're on the end of a little neighborhood, but yet we're right next to busy roads and pretty much everything.

Even when i went to work and back with how cold it was the tires didn't heat up on the 2 mile drive home from work the past couple days. Checked them when i left and when i got home and still the same. Just waiting until the rain stops now so i can go out and fill up.

 

I'm in the middle of a 2400 mile road trip. I started in Texas where temps were in the 60-70 degree range and I was getting 33mpg average at 75 mph average, with 32-34 psi in each tire.

By the time I hit mid-Oklahoma, temps were down into the 30s, I was getting closer to 30mpg, but tire pressure held steady.

When I hit Kansas, temps hit single digits and everything went to hell. 27mpg at 75mph average, tire pressure around 28 psi across the board. I left my car in KC overnight and rode to Omaha in my buddy's Cobalt SS/SC (nice ride, but I'll take a functional vehicle over what basically amounts to a 2-seater with a fugly spoiler). When I got back to pick up my car the next day, it was 0 degrees outside, and the tires had sunk to 25 psi. I drove it a few miles to let the tires attempt to warm up so I got a more accurate reading, and they hit about 27 psi across the board, so I refilled the air and it's up around 35 psi across the board now.

I guess I'll need to release some of the air on my way back down south to avoid overpressurizing the tires. But yeah, I'll definitely be looking forward to getting better gas mileage and avoiding frostbite when I get back to Texas.

 

On a semi-related note, when I got my SS four months ago, I gave my GP to my 17-year old daughter to drive. Last week I saw the GP parked in the driveway and thought the tires looked awfully low. I got out the tire pressure gauge, and found out that two of the tires were at 18 PSI, and the other two were at 22 PSI. I immediately filled the tires to 30 PSI. I don't know how long she had been riding on low pressure, so who knows how much damage she did to the tires. The GP seemed to ride and steer fine once I fileld up the tires, but I am going to monitor the situation.

You can teach a kid how to drive responsibly, but actually taking care of the car is a different story. I asked her if she has checked the tire pressures since last week, and of course she has not. Ugh.

 

yeah u might wanna keep n eye on that car.. for her safety n for the sake of the tires
also she's a young girl driver.. and from my point of view they
are the worst at driving and really bad at keeping up with maintence (tires, oil, ect..)
.. i would know i have several friends under 20 and a sister who is 17..
she once left the ebrake on for like 30 min while driving till she finally called me
and said.. paul why is my car taking off so slow, i like REALLY have to give it
gas to make it move.. come to find out she left ebrake up.. now she just
wont use it cause she thinks itll happen again..

 

i believe that the nitrogen works , but there is 1 thing i don't understand. do they evacuate the air with a vacume pump 1st? if not then you can't be getting much nitro for your $. anouther thing i do not understand- the perfect operating temp for a gas engine is 175 deg f . so then shouldn't mpg be better / the cooler the weather/coolant temp as long as the coolant temp doesn't get too low? also temp here in nc went from 22 yesterday to 68 today , my tire pressure jumped 3psi.

 

Nitrogen is a tempest in a teapot, and slight loss of tire pressure is only a very minor constituant of why mileage declines in cold weather. If you doubt it, do nothing but scrupulously maintain tire pressure and watch your mileage still decline even faster than your wallet contents after putting nitrogen in your tires.

A considerable factor is the winter fuel blends that are noticeably less efficient than summer blends. How a fuel that causes you to have to burn more of it to do the same work reduces pollution is known only to Nancy Pelosi.

The biggest thing is the temperature itself. Driveline resistance is markedly increased in cold weather because of the gear lube, wheel bearing grease, etc. becoming stiff. So is rolling resistance, even when fully inflated. The other thing is that combustion efficiency is highly temperature dependant. You just don't get as much energy out of combustion when the air is cold. This is unrelated to charge density, which is why CAI's increase power. CAI's kill mileage in cold weather. Anyone remember the preheaters and heat risers that used to be on cars?

 

Oh, PLEASE.... That is absolute BS. Gas is gas and conforms to the Ideal Gas Laws of science! Temps rise, they expand; temps fall, they contract. There is absolutely NO myth, lore or BS marketing that can change that FACT!!

PV = nRT... Look it up.... educate yourselves and report back.