ejbarnes

This may be a dumb question...
Why don't we use nitrogen in bike tires?
I have nitrogen in my automobiles an the pressure stays steady ot and cold for years.
Seems the molecules are too big to get through the rubber like plain air under pressure and CO2 is even less likely to stay in the tube/tire.
Again. why not use nitrogen?

AEO

bike tyres don't heat up as fast as car tyres.

also 78% of the air is already nitrogen.

rhenning

Nitrogen in tires reminds me of PT famous Barnum's statement. There is a sucker born every minute." Roger

HillRider

Nitrogen fill for car tires is one of the better recent scams. Air is 78% Nitrogen already so if the molecules of N2 are "too big to get through the rubber" then the molecules of O2, which are the same size, should be as slow to leak out.

CO2 is a different story since it appears to have a significant solubility in rubber and thus diffuses through it faster.

I_bRAD

I would like to try this, but have been unable to locate a Nitrogen floor pump.

JanMM

You don't ever have to add more? For years?

HillRider

It's easy. Just use your regular floor pump and throw away the O2 as it comes out.

BTW, I've always thought P.T. Barnum was too conservative in his estimate of the frequency of suckers.

fuzz2050

I don't know about you guys, but I think there might be something here. Argon would have one hell of a time escaping, or Xenon, or any of the big noble gases.

And come race day, let it all out and refill with hydrogen for a substantial weight saving.

rm -rf

Bike tubes are a lot thinner than car tires, so air diffuses out quicker.

If nitrogen was a lot less likely to leak out, you would get this situation:
Since nitrogen stays in my tires, each time I add air, the oxygen and argon leaks out, leaving the nitrogen behind. So the nitrogen percentage increases each time, and I have to add less and less air each week. Now I only add a little air once a month or so.

Doohickie

Nitrogen is st00pid. Normal air is fine.

HillRider

I remember many years ago that track racers filled their tires with helium. They claimed all sorts of lower rolling resistance, etc. etc. ....

wrk101

+1 If pure nitrogen was so good, then eventually, the quote above is what would happen.

+1 Anyone have a nitrogen floor pump?

+1 Total waste of money. https://www.msnbc.msn.com/id/19353980/

Gonzlobo

We use bottled nitrogen in our jet's tires, primarily because the bottled gas doesn't have any water in it (it would freeze at -50C).

spacerconrad

Yep. We'll use it in anything at or above the King Air level. Smaller planes just get air, and we don't have any trouble with 'em.

DM4

Oh come on, everyone knows there is no such thing as a nitrogen floor pump. What you do is fit your regular pump with an oxygen filter.

sch

Gonz has hit on the real rationale: dry nitrogen is used to keep water
out of tires. Any one with experience with air compressors is aware
they do a good job of concentrating the residual humidity in the air
and it ends up condensed inside the storage tank and sometimes,
depending on how the system is plumbed in the air lines resulting in
some water inside the tire. Modern car tires have such low permeability
that this is an extremely minor concern, hence the opinions expressed
that the use of nitrogen is a scam. As others have pointed out if O2
preferentially leaks out then the content of the tire would drift in the
direction of higher and higher N2.

Mondoman

As G suggests, it's not that nitrogen is "better", but rather that it's easily available in moisture-free form. Environmental temperature changes can significantly affect car tire pressure as the moisture inside evaporates (increasing pressure) or condenses (reducing it). Bike tires are typically inflated to much higher pressures, so variations in pressure due to moisture are much less significant.

DieselDan

Same reason why race cars use nitrogen instead of ambient air. Condensation builds up in the air tank of air compressors and water transfers into the tire. That water will start to boil and distort the tire, causing a sudden blowout. Street car tires and bicycle tires don't have near the heat and stress put to them as any race car tire.

nitropowered

What dan said.

Honestly, do you want to carry around a $200 tank and $200 regulator that weighs 50+ lbs to races every weekend?

FLYcrash

I'd just like to say that CO2 is a very minor constituent of air. Typical air is about 77% nitrogen, 21% oxygen, 1% argon, and 1% water vapor. The CO2 is a tiny impurity typically measured in parts per million. You only need to worry about it if you're using those little CO2 cartridges. And that stuff's acidic! Try to inhale some from a block of dry ice sometime...or, come to think of it, maybe you shouldn't try.

+1 to all who say nitrogen doesn't make a difference. But I would think that the gas being dry could make a difference even in bike tires.

I think it's a brilliant idea to use hydrogen in bike tires. Totally shave a few grams from the bike. Forget that it's explosive; for me, shaving grams is a spectator sport and a gloriously hilarious one at that.

I_bRAD

If you save the oxygen you filter out and breathe it before your ride you'll be crazy fast.

JustCruisin

Well lets see we used Nitrogen in the shocks and forks in our race bikes(MC). Why? heat expansion and as said vapor the mono shock on a Pro Moto-cross race bike is HOT after a race! Is it better than 0xygen in tires, yea but not enough you will probably ever notice it in a street tire,other than it will probably hold set pressure about 3 times longer. So you can check pressure a bit less often.
I promise the kenetic energy(gas expansion)(caused by heat)of normal air will blow a shock seal in a hard race. All said if your paying $5 buck a tire your getting ripped.

deraltekluge

Also, N2 is nearly inert, and won't oxidize rubber and other materials the way O2 will. But...in the case of bike tires and their operating environment, the difference should be insignificant.

If it were true that N2 doesn't leak out, your tire pressure would never drop below about 78% of what you started with, filling it with ordinary air.

urbanknight

So it sounds like it's useless for floor pumps, but can they put this in cartridges instead of CO2? That sounds like a reasonable application to me.

UnsafeAlpine

Use air for car or bike tires. Slow leaking is one of the stupidest things I've ever heard.

Race cars use Nitrogen as do high performance aircraft. Both of these vehicles generate so much heat that even that 12% air expands and creates an increase in tire pressure. That's not a good thing when tire pressures need to be exact. You will never generate the amount of heat that will affect your driving or riding negatively.

Whenever your car tires start getting low, just put air into it. Nitrogen is a waste of money.