Tires filled with helium: what?

[Trwhouse]

Hi all,
I fill my tires with air, so if I ever get a flat, I have air on hand to fill them back up with.
Yours,
Todd





p.s. I'm sorry, the helium thing was so ridiculous, I couldn't resist. 

[Alphamazing]

I realized it was a silly thing, but I thought it was an interesting question which would give people to show how nerdy they are  .

I knew that the Helium wouldn't make that much of a weight difference compared to air, but was more interested in the decrease of rotational inertia and the possible benefits.

[RVertigo]

I was busted as an avid MythBusters watcher...  I DVR that show...

They were talking about how the loss of weight would theoretically cause the ball to fly a shorter distance... That made me wonder what would happen if they put a heavier gas or perhaps a liquid in a football...  That's how geeky I am.

[Ed89]

Several years ago...

Indeed.  Actually, hot air might work just as well, since it will have the same buoyancy effect as helium.  With the rising gas prices and such, it might be a worthwhile venture to start a hot air tire business.  You probably won't have any trouble producing ample supply of hot air.   

[surlybruce]

Where were you people when I was trying to get my grade 10 !

[budget speed demon]

Several years ago...

Indeed.  Actually, hot air might work just as well, since it will have the same buoyancy effect as helium.  With the rising gas prices and such, it might be a worthwhile venture to start a hot air tire business.  You probably won't have any trouble producing ample supply of hot air.   

I imagine that the air inside the tire would heat up as the tire itself heats up.

Although I wonder how hot it gets. And how hot it would need to be to offer any weight savings.

While we're attempting to make the GS lighter, why not spend some time building yourself an aluminum frame, then how about an aluminum or Carbon fiber gas tank? 

[scratch]

How hot would it have to be to overheat the tire?

[vtlion]

Nitrogen is probably used because of it's easy commercial availability, low price, and relatively large molecular size.  As far as i can tell it is all about predictability in the fill gas properties.

Helium will effuse (leak) too quickly (Graham's Law of Effusion for you calculation-monkeys out there) resulting in rapid loss of pressure.  A quick estimate is that He will leak about 2-3 times faster than N2.

Dry gas mixtures can be purchased as well, so theoretically the specific heat and leak-rate of the gas within the tires could be 'tuneable'. 

I suppose one could use any large gas they wanted to fill a tire.  Argon, carbon monoxide, laughing gas.  How about Radon?  It is inert, leaks very slowly, and you won't need headlights anymore because your bike will glow in the dark 

[GeeP]

After a two month span, they were able to log a 34% increase in MPG.

I think someone misplaced a decimal point or four.   

Nitrogen is used in aircraft tires because it is stable and dry.  Also because it's available on-site.  High pressure nitrogen is used in landing gear struts.  In addition, aircraft tires operate at much higher pressures than most other tires.  Many in excess of 200 PSI.

[Mr.7]

I think I will keep using air.

I don't like to study the periodic table everytime I get a flat tire

[sledge]

I think an immediate reduction in fuel consumption by 34% is optomistic to say the least. If it was as easy as that everyone particularly truck and bus companies would be doing it by now and saving a fortune. Didnt George Bush in the last State of the Union address talk about reducing Americas dependance on oil. If it was possible to save 30% of it by filling tyres with Helium wouldnt he be making it law to do so.

[tophyr]

And just to clarify, gravity is a force, not an acceleration. 

Actually, the unit "G" is a unit of acceleration, not force. 1 G is an acceleration of 9.8m/s^2, regardless of how much force is required to obtain it. I've already forgotten what the context was though, wow. Gravity = force, G = acceleration.

And, in case anyone was wondering, hot air will both reduce the weight of your tires as much as helium, and won't leak out fast, either. For only $45 (S&H extra) I can personally fill up two large 10L tanks of heated air. Disclaimer: Air may cool during shipping. Seller not responsible for reduction of effectiveness.

[GeeP]

Disregard tophyr.  He's selling product with a shelf-life.  I'll sell you one pint of Vacuum for $10.  That's $0.00 per ounce!  Shipping included!  No expiration date!  Guaranteed for as long as you own the container!

Coat both the inside and the outside of the tire with Vacuum, and your tire will operate at an absolute pressure of 0 PSI.  Use it as a shampoo and nobody will ever call you an airhead again.  Coat the inside of your Wileyco with Vacuum and see a 50% increase in power!

WARNING:  Do not use Vacuum on air-cooled engines, serious engine damage will result.  Do not use Vacuum near induction systems.  Do not inhale Vacuum, death may result.  Reports associate Vacuum with severe abdominal cramping, so do not eat Vacuum.  Always store Vacuum in a sealed container.

Oh!  I also have eleven 55 gallon drums of aircraft propwash for sale.  $30 a gallon and it's yours.  For you marine guys, I have some freighter propwash on order.  Should be in next week.

[rtcpenguin]

Well, even according to the MythBusters, there was a weight difference when they used Helium to fill the football...  In fact, the helium filled ball was lighter than the empty ball...  But, only by a few grams or something...


It would probably make a weight difference in a tire, but I can't imagine anyone would use it because it leaks so much.

Of course it makes a weight difference, but that difference is negligible in a 400+ lb bike and not so much in a 1/4 lb football.

[Ed89]

Several years ago...

Indeed.  Actually, hot air might work just as well, since it will have the same buoyancy effect as helium.  With the rising gas prices and such, it might be a worthwhile venture to start a hot air tire business.  You probably won't have any trouble producing ample supply of hot air.   

I imagine that the air inside the tire would heat up as the tire itself heats up.

Although I wonder how hot it gets. And how hot it would need to be to offer any weight savings.

While we're attempting to make the GS lighter, why not spend some time building yourself an aluminum frame, then how about an aluminum or Carbon fiber gas tank? 

I was just pulling gsmetal's leg, since he is trying to pull everyone else's leg. 

It doesn't matter much how hot the tire gets sine the volume is pretty much fixed.  So the air density is approximately the same whether the tire is hot or cold (no air leaks out), although the pressure will change.

Cheers,
e.

[denman]

our work truck had a low tire so we filled it with freon,and it was huge when we got back to the shop.   see ya.

[denman]

that was like 25 years ago when we did that.

[scottpA_GS]

I agree that taking a big dump or cutting your finger nails would give greater weight reduction 

Good topic though.. I like all the crazy mathmatical responses..  Nerds