Tire Pressure ?

[WOTW2E]

The advantage of nitrogen in a tire is that there is little change in pressure due to changes in temperature. As noted air pressure will increase as the tire heats up. Nitrogen is more stable, thats why it is used for nascar where they are making 1/4 psi adjustments.

Anybody have any first hand experience of an increase in mpg using nitrogen on our daily drivers?

 

[Chris]

Nitrogen is just the latest marketing buzzword for the tire industry.

Your tires already have 79% nitrogen in them. The reason nitrogen leaks out more slowly is their molecules are larger than oxygen's. The individual oxygen molecules slip out between the molecules in the tire. The aviation industry uses nitrogen because it's inert, not because it doesn't leak. They check pressures pretty regularly and no flights are long enough to have a measurable drop.

As far as temperature-effect PSI changes, your tires were engineered under the assumption that they would be filled with air and any heat-related pressure changes were factored in.

 

[cigdaze]

As far as temperature-effect PSI changes, your tires were engineered under the assumption that they would be filled with air and any heat-related pressure changes were factored in.

Yep. Exactly why the stamp reads "Max Load at XX PSI Cold."

 

[outriggers]

I use nitrogen in all my tires. There are some other advantages, althought I think the extra MPG thing is bs. If the pressure is rite, its rite. There is no water or moisture in nitrogen. Ever have a aluminium wheel corode to a tire or have the bead corode so it leaks? I have also been told that in tires that sit alot that they dry rot less because there is no oxygen. The snow tires for my car were stored all summer, I put them on in December and the pressure never changed. I think thats were the extra mpg thing comes from because most people don't check so they are lower than they should be. I buy it by the bottle from a gas outfit. I do think its their is a profit motive and I wonder about the quality. Like Chris says in aviation the pressure is checked alot. If the pressure is low in one tire by a %, that tire and the one next to it also has to be changed. If one tire was low that means that the one next to it was overloaded. On the airplanes I fly, each main gear tire has about 40,000lbs riding on it. (4 tires to each truck), with a 225 mph speed rating. Heat is also a big issue, you don't want oxygen in a very hot tire. Sorry totally off topic, my .02 Doug

 

[KYElimEagle]

Lower pressure in my front tires on my F-250 leads to more uneven wear on my front tires. I run 75 lbs. not as good ride but seems to handle better and wear better. I am sure better mileage.

 

[US1Fountain]

Anyone ever use the chaulk method to determine tire pressure?

 

[Pachanga]

Lower pressure in my front tires on my F-250 leads to more uneven wear on my front tires. I run 75 lbs. not as good ride but seems to handle better and wear better. I am sure better mileage.

I just received a letter from Ford warning about running tire pressure to low on my 250 4X4. Apparently some trucks will develope a severe shimmy after hitting a bump! Too stop the shimmying the truck has to be brought to almost a complete stop. Ford says this is due to running tire pressures too low.