What kink of air in the tires?

the air that's in the tires is just regular air.. which is like 78% nitrogen.. lol.. if you want to fill them, then by all means go ahead. is it necessary? well, most things we do to our cars aren't.. lol.

to properly fill them, you will need to go thru cycles of purging and filling to increase the purity levels.. afterall, when you purge them down initially down to 1psi (i'd probably suggest 3psi so the tires aren't so deflated).. you're still going to have that amount of air in the tire when you add nitrogen to it... it's not going to be 100%

even after a few cycles.. it won't ever be that high and you'll probably never reach it.. but you only need it to be like 93% or so anyway to get the benefits that you so desire.

do you need to re-balance them? uhh.. did you take the tire off the rim? no? well.. you don't need to re-balance them.

 

I'm no expert, but I've been suspicious of the rationale in the air vs Nitrogen debate. We had compressed air in the labs where I worked, and those lines were loaded with compressor oil and also condensed water (would be bad for tires, IMO). I'm thinking that the main benefit of using Nitrogen is that these contaminants are not there. The argument that air is 80% Nitrogen (so why bother) misses that point.

 

Nitrogen for automobile tires is snake oil. There are advantages for aircraft and race cars, but no advantages for the family car. Furthermore, what most tire companies call nitrogen or "Nitronized" is really plain air with a marginally higher concentration of nitrogen. It's main advantage is in removing money from customers.

What you really want is a dry fill. Ordinary air, properly dried, is every bit as good as nitrogen. Use a good water separator or desiccant cartridge on a compressor and all will be good.

Tom

 

it is a silly point when people are too fixated on the composition of air.. when nitrogen's benefits are really what you pointed out..

it's not about the air itself and its properties.. but yes, nitrogen does stay stable over time a lot better.. and not affected as much from temperature changes.. but it's really the water vapor (well, lack thereof) that gives nitrogen the upper hand. but how much it'll actually save you in maintenance costs and its benefits will only be noticeable very long term.. especially for the typical passenger car.

most of the benefits from nitrogen only really show in vehicles that have the necessity and power that need it.. i.e. vehicles that are on the racetrack.

otherwise.. yes.. for the average person.. it's snake oil.

 

Bust out your air compressor and fill them. The "nitrogen" at the tire shop is regular air with about 5% more nitrogen.

 

Nitrogen tire fill is a solution in search of a problem.

 

Nitrogen is affected by temperature just as much as any ideal gas, including good old air. Nitrogen also has a diffusion rate that is for all practical purposes the same as air. Furthermore, tires are designed to resist diffusion, for obvious reasons.

As for racing, there are three advantages to nitrogen for tires:

1) Nitrogen can be stored in liquid form, providing a compact and convenient method for refilling tires.

2) Liquid nitrogen is inherently dry, the water vapor being removed during the liquefaction process.

3) Nitrogen does not support combustion, which can be an advantage in a crash situation.

Nitrogen expands and contract from temperature just as much as any ideal gas. The advantage for racing is predictability. While dry nitrogen still expands as the tires heat, it does so in a predictable fashion. This allows racing teams to precisely control tire pressures, which is important in high performance driving.

Ordinary family driving is not consistent enough to benefit from this fine level of inflation control. Also, hopefully, ordinary family driving is done at a level further removed from disaster.

Tom

 

If we used Helium the unsprung weight would decrease.

 

We have had this thread about 15 times, and eventually someone has to make the helium comment. Generally it's followed by comments about argon and uranium hexafluoride.

Tom

 

Well, it makes about as much sense.

 

I'm very happy with my bicycle pump for top-offs.

Now, just a random thought: N2 is less active chemically than O2, so perhaps people who end up discarding tyres due to age rather than wear might have a justification ? Personally, I'd just buy a cheap tire with low treadwear life even if true.

 

When is the last time you saw a tire discarded due to aging on the inside? It's always because of dry rotting on the outside, which no type of fill gas is going to change.

 

That thought occurred to me too, but then I haven't looked at a cross-section to say the inner and outer surfaces are not proximate. Or, for all I know the inner aging changes a characteristic of the tyre that predisposes it to accelerated outer aging, e.g. cracking.

You do realize I was only musing aloud, right ?

 

That about sums it up.

 

uranium hexafluoride makes for a great cavity fighter, right??

 

Where do they find a oxygen free atmosphere to race in?

 

I believe that exposure to enough means that cavities are no longer an issue.

 

It's highly toxic and reacts violently with water so it wouldn't take much to make tooth cavities the least of your problems.

 

My point exactly.