Nitrogen in tires

[Tomster]

Well, we all use it on airplanes too because it’s clean, dry and inert but air works too. I think nitrogen is of marginal benefit to racers. Zero benefit on the street. There’s probably a white paper out there but I haven’t seen it. If I had Dean’s budget, I would have a nitrogen bottle instead of a ratty old compressor

With respect to street use, yes, completely useless.

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[moreause]

i like this one

[ame]

 

[tom_sprecher]

I saw Dean Martin had a big ass bottle of nitrogen at the track. I'm sure there is a very good reason he, and other racers use it.

At the track I used it for filling tires and running the impact wrench for the lug nuts. Cheaper and more compact that a compressor.

 

[snaproll]

With respect to street use, yes, completely useless.

My results were the same as Tiff Nedells. The true badasses use N2O to run their air tools. :cheers:

 

[FP350S]

My newest car is 1.5 months old and came with Nitrogen filled tires at delivery (which I did not pay for). With the tempatures dropping this week in Texas to just the mid teens my car has already alerted me to fill due to a low tire pressure change.

 

[TheDeadCow]

In a street car it's not beneficial IMO.

When I raced karts (sprint karts) it was quite helpful. Keep in mind 1/2 psi change in a kart tire is very noticeable on any corner. Using N2 allowed me consistently hit my hot tire pressures VERY easily. Basically with N2 I'd see +3psi increase due to thermal expansion from cold to hot pressures regardless of the ambient/track conditions. Using compressed air I would see anywhere from +4-6psi hot to cold.

One thing that made N2 feasible for me to use was the fact that kart tires and small and you can easily get all the air out before you fill N2. From what I understand it doesn't quite shake out like that for car tires (i.e. equipment is too expensive for possible gain).

It works as intended. Any of you that have done any type of racing will know there's a lot to do on race day and any little thing helps. Worthwhile? That depends on you budget/goals/competition.

 

[H6G]

Well, we all use it on airplanes too because it’s clean, dry and inert but air works too. I think nitrogen is of marginal benefit to racers. Zero benefit on the street. There’s probably a white paper out there but I haven’t seen it. If I had Dean’s budget, I would have a nitrogen bottle instead of a ratty old compressor

These guys know that it’s more stable during temperature swings (pressure remains comparitively same, so does handling)......diffuses slower and has no water vapor - pure nitrogen alone.

When it comes to aircraft..... since air contains oxygen, and oxygen is one of the components of the deadly “fire triangle”, only Nitrogen is used.

Aircraft tires run at a deflection of about 30% as opposed to automotive ones typically 10%, and are not designed to be continuously run. As they roll, the heat builds up. They do not reach an equilibrium temperature as ground tires do.

The use of Nitrogen will also tend to reduce wheel corrosion, tire fatigue and the risk of fire when fusible plugs melt due to brake overheating.

 

[Trackaholic]

Waste except for race teams that need every advantage they can get, no matter how small.

On a track day you are only running 20-30 minute sessions typically, so your pressures will go up only a certain amount during that session. I find that a single session isn't enough to reach steady state temps, and therefore I am checking and adjusting pressures between each session anyway. Any minuscule benefit provided by nitrogen in terms of more stable pressures is wasted since I am adjusting things anyway.

As far as keeping air in the tires, I just haven't found that to be an issue. The temp changes due to seasons changing requires pressure updates more frequently than air leaking out, so once again I am adding and subtracting air whether or not nitrogen would be used.

If someone wants to add it to my tire for free, that's fine, but I won't pay extra for it.

-T

 

[Austinj427]

I take the 78/22 approach when I fill my tires.

 

[Tomster]

These guys know that it’s more stable during temperature swings (pressure remains comparitively same, so does handling)......diffuses slower and has no water vapor - pure nitrogen alone.

When it comes to aircraft..... since air contains oxygen, and oxygen is one of the components of the deadly “fire triangle”, only Nitrogen is used.

Aircraft tires run at a deflection of about 30% as opposed to automotive ones typically 10%, and are not designed to be continuously run. As they roll, the heat builds up. They do not reach an equilibrium temperature as ground tires do.

The use of Nitrogen will also tend to reduce wheel corrosion, tire fatigue and the risk of fire when fusible plugs melt due to brake overheating.

I do recall when I flew 747's you could overheat the tires (at or near max gross wt) in a very long taxi. Yes, aviation is more demanding. However, this is not aviation and although the principle is the same, the application is a little different (depending on what track you are running). At Daytona this year (which was different from last year because it was a lot warmer), my pressures went from 28 PSI cold to around high 30's to almost 40 hot (Alignment setting set by Daytona track experts). This is a big spread. I had my dash set to monitor TPMS pressures because the ambient temperature was much warmer this year. Subsequently, the pressures ran higher. At the end of each session, I would check tire temps and pressures and adjust accordingly. The harder I drove the car, the higher the tire pressures got. It is critical to keep your hot temp pressures within the allowable range. One specific example that I can think of is a BMW on the front stretch blew a tire. He probably wasn't monitoring pressures like I was, but when you are dealing with the maximum speed of a vehicle, I think that nitrogen may have made a difference.

My reasoning is based upon advice from people who race. Higher speeds equals higher tire pressures. Take a dry inert gas like nitrogen and heat it compared to normal pressurized air and my bet is that the dry nitrogen will expand less than normal compressed air (which contains water, oxygen, and nitrogen).

For people like us, probably not much of a difference, but when you are pushing max hot pressure of a tire, a few PSI is huge. I think the guy who blew the tire on the front stretch would agree.

 

[Zitrosounds]

At the track I used it for filling tires and running the impact wrench for the lug nuts. Cheaper and more compact that a compressor.

Nitrogen is cheaper than air??? Please explain..

 

[snaproll]

These guys know that it’s more stable during temperature swings (pressure remains comparitively same, so does handling)......diffuses slower and has no water vapor - pure nitrogen alone.

When it comes to aircraft..... since air contains oxygen, and oxygen is one of the components of the deadly “fire triangle”, only Nitrogen is used.

Aircraft tires run at a deflection of about 30% as opposed to automotive ones typically 10%, and are not designed to be continuously run. As they roll, the heat builds up. They do not reach an equilibrium temperature as ground tires do.

The use of Nitrogen will also tend to reduce wheel corrosion, tire fatigue and the risk of fire when fusible plugs melt due to brake overheating.

I agree that N2 is most use useful for corrosion and fire issues on planes (mostly theory because the damn wheels still corrode) but the pressure issue are within rounding errors, not 2 or 3 pounds on a go kart tire. I maintain that Inflating tin top race car tires with N2 is a waste of time and money. But I’m open to the science.

 

[JAJ]

I was told that there is less pressure increase when running between hot and cold temps at the track. I almost did nitrogen this year at Daytona, but again, I ran out of time.

I saw Dean Martin had a big ass bottle of nitrogen at the track. I'm sure there is a very good reason he, and other racers use it.

Two points:

First, the benefit of nitrogen is that it's dry. Dry air will work just as well. Moisture in the air causes a bigger pressure change as the tires warm up.

Second, nitrogen is required for setting the pressure in remote reservoir racing shocks. I imaging that's why it's in the Kohr pit. Tires maybe, shocks for sure.

 

[Norm Peterson]

Here’s a FifthGear link, but it’s unlikely to resolve the question to a skeptics satisfaction.

What he says about moisture and oxygen diffusing through the tires is correct, but the effects from them occurring with the use of "regular air" are not nearly as meaningful or as critical to the mission in a daily-driven Mustang as they are in a F1 car or in commercial and military aviation.

This has been discussed at an engineering level (real automotive and tire engineers), and the practical answer is that the value isn't worth the usual cost. Nitrogen still follows the gas laws, the same way that oxygen and other gases do, and it's the typically drier product that's giving any benefit.

What I've found, using undried regular air at whatever ambient humidity exists at the track, is that after a couple of 20-minute HPDE sessions and bleeding off pressure above my target hot pressure between them, inflation pressures have stabilized to the point where no further air need be bled out. Yes, I do need to put some air back in for the much less strenuous street driving, but I wait until the next day for that so I can go back to setting cold pressures.


Norm

 

[DANA44]

Waste
I am not aware of a tire installer that uses it to seat the bead at tire installation . This would be the starting point of a true purge. But that use would be a heck of a lot of nitrogen for a shop. What the guys with the green caps do is just a top off. There's still atmospheric and moisture in the tire.
I've never used it to fill tires unless in a jam but always have a tank handy next to the vacuum pump.

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