I saw a piece on the news about using nitrogen to fill tires. The claim is that rubber doesn't break down as fast resulting in longer lasting tread wear. Said that it can also be mixed with regular air when inflation is needed. Has anyone gone this route?

 

I haven't had a chance to try it, but there is a tire place around here that has been running ads touting the benefits of nitrogen inflation. It keeps tire pressures more consistent for a longer time period, apparently.

 

Costco offers it too, but I haven't looked into it myself...

 

I hope this thread stays alive for a while as my new Kosie wheels have the dual valve stems for nitrogen. I'm interested in the benefits, cost, hassle factor and whether or not air introduced into a nitrogen filled tire creates problems.

ripley.

 

I think regular air is good for those that check tire pressure

regulary...like me. :smile:

 

From high school chemistry we probably all remember that air is 78% nitrogen, 21% oxygen and 1% misc. other gasses. From what I’ve read about filling tires from nitrogen, the benefits fall into three categories: less pressure variation as the tire heats up, less pressure loss over time, and longer tire life. The reduced pressure increase as the tire heats up seems to be attributed to the nitrogen being dry. There is no liquid water in the tire to change phase. Presumably, we can get the same benefit by using dry air. The reduced pressure loss over time is due to the tire having a lower permeability to nitrogen than oxygen. If you are regularly checking your pressure, this isn’t worth much. The longer tire life seems to get attributed to having the correct tire pressure and reduced oxidation of the inner layers of the tire. I don’t think many MINI tires are dying of old age (oxidation).

If someone offered me free nitrogen, I’d take it. But I wouldn’t pay much for it.

 

I have it in both sets of wheels and tires. Haven't noticed either a benefit or drawback. It cost me something like $5 a tire. Tire pressures remain stable each week but I really wasn't checking regularly before I got them filled with nitrogen.

 

As mentioned above, the primary benefit is less pressure variation due to reduced water vapor.

Primary use would be for racers looking to minimize pressure change during a race. I see no reason to spend the money for a street car.

 

Stability due to moisture resistance is the advatage. Introduce atmosphereic air, and you bring vapor, and reduction in stability, or pressure over temperature changes.

When its readly available, it will be the way to go.

Alex

 

also, isn't nitrogen slightly lighter than air? if not, then what's the benefit???

 

Seen as every F1, CART, IRL and NASCAR team use Nitrogen in the tires - the benefits are very real.

The only person benefitting when you use it on the street is the owner of the shop charging $5/tire. $20 for all 4. Now that's a money making deal.

FYI, a large bottle nitrogen refill costs me less than $25 and lasts almost a season of autocross tire refills and tire changes.

Anyone need their tires filled with nitrogen? Only $4.99/tire!!

Unless the tire is completey purged of air, using a special setup (about $1000), the process is not reliable. We mount all our tires using nitrogen, and still purge each tire to completely remove any remaining air.

Funny thing is - I have never had problems with the inside of the tire wearing out or aging. Keeping tread on the outside though, that's a whole different problem.

Bones

 

If you like spending cubic dollars on your street car for imperceptible gains, then nitrogen filled tires are for you.

If you track your car, it's different.

Mostly though, if your tracking a high horsepower, formula car like a Champ Car, F1 Car, IRL car, or even a stockcar, then it's actually of real benefit, seeing as so much of the suspension system is predicated on the deformation of the tire structure, and flex of the sidewall. The specific rubber composite, and the behavior of the tires at optimal temperature are the single biggest factor in the mechanical performance (I'm not addressing the aero setup) of a car like that.

EDIT: Ok, now that I read all the threads, I'm being redundant to Bones... but you get the idea.

 

If you're going exotic, might as well try hydrogen. Those heavy run-flats and S-Lites are just crying out for hydrogen.

 

I am fairly sure that Col. Bobby is being sarcastic.

But just some info for those that may think this is a good idea. I know that teams have experimented with "lighter than air" gases for tires. I think the problem with hydrogen and helium has to do with molecule size, and the molecules pass through the rubber tire easily, therefore losing pressure.

Not to mention the flammability of certain gases. Remember the Hindenburg?

 

I've talked to chemists and read this discussion on many other boards, and the molecule-size issue is bunk. I would *assume* that tire explosions are a bigger issue with hydrogen.

Nitrogen offers the benefit of having a predictable thermal-expansion rate. You can easily predict what your PSI delta will be between cold and hot, and this is part of why race teams use it. Preventing vapor is another key benefit, but removing that 1% of unknown gases that expand at unpredictable rates is the principle benefit.

If you're running a $1M car around a track and competing for millions of dollars in prize money, then why screw around with even one variable (other than the driver)?

 

Helium tires... careful that you dont float away!

 

Wow, Nitrogen really is they way to go! (If you own a supercar)

http://www.motortrend.com/features/p...igh_speed.html

"Michelin: Traditional "air" is easily affected by temperature. As tire temperature increases the tire pressure expands considerably that changes the tire's contact patch and sidewall stiffness characteristics. Nitrogen is much more temperature stable than normal air so tire pressure remains much more consistent."

 

too bad everything doesn't remain consistent when things heat up.

 

Why not use helium? It's lighter than air or nitrogen and should reduce unsprung weight.

 

Most likely because 78% of FREE AIR is nitrogren whereas they probably have to actually produce the Helium and it costs more. Besides, it may not be as stable as Nitrogen.

 

You don't "produce" helium - you get it from underground mines.

The stuff is rare enough and important enough that the US maintains a strategic reserve of it.
http://acswebcontent.acs.org/landmar...roduction.html

One of its virtues is that it is completely stable and combines with nothing.

 

One, Helium seeps through the rubber. You will have a flat tire over night, it's been tried.
Two, Helium may make things lighter on a scale, but mass stays the same. It will not help rational weight.

 

This sounds like BS to me. O2 or N2, at the low pressures in tires, are essentially ideal gasses. They both expand & contract at the same rate as a function of temp. The point about water is semi-valid; if there is enough water to condense when the tire is cold, then upon warming up there would be a greater pressure increase. However, this could be avoided by using dry air just as well as dry N2. Also, I have a hard time believing there would be enough water in the initial fill air to make much of a difference between hot - cold.

The positive aspect of N2 is clearly that the tire will stay inflated longer. Since the tire (initially) contains no O2, O2 will diffuse thru the rubber into the tire, partially offsetting the N2 diffusion outwards. This is like the Nike Air bladders in shoes - they filled those with sulfur hexafluoride, so that as the bladder stretched over time the inward air diffusion helped keep the bladder filled up. In this case, the SF6 diffusion thru the bladder was nil, unlike N2 or O2 thru the tire. Generally, these two molecules have similar diffusion rates, as they are both non-polar and about the same size.

 

Here is the full quote

Michelin: Heat management is an important factor since internal temperatures can quickly hit 300 degrees F at 218 mph. Michelin designed the Michelin Pilot Sport PS2 tire to limit peak internal temperatures to 250 degrees while evenly distributing temperature across the tread surface.

Motor Tend: What are the general tire psi requirements above 200 mph?

Michelin: Pressure should be no lower than 40-psi cold if you're planning on running at such sustained speeds.

Motor Tend: Why do many race teams inflate tires with nitrogen versus traditional air?

Michelin: Traditional "air" is easily affected by temperature. As tire temperature increases the tire pressure expands considerably that changes the tire's contact patch and sidewall stiffness characteristics. Nitrogen is much more temperature stable than normal air so tire pressure remains much more consistent.

 

chows, are you thinking about going 200+mph on your MCS down
one of your side streets?

ibftl!!!