bit of a stupid question but....

[nechaus]

Can you fill the bike tyres/tubes with helium ?? would it make the setup lighter? and would it work?

[markobetti]

you can fill it with water if you want but you will not get a water - jet . Helium inside tires to make them lighter...man forget that ...

[rojitor]

The wheel will not be noticeable lighter, its particles are smaller than air's so the tyre will lose the pressure in no time,hellium is more expensive than air (free so far) therefore you better not bother.

[nechaus]

Forgotten lol

[Ypedal]

I"m going to add this to the faq .. lol...

[full-throttle]

It's been asked many times before
http://www.bikeforums.net/showthread.ph ... weenies...

as well as helium filled frames
http://weightweenies.starbike.com/forum ... p?p=520678

you're better off filling your tyres with latex sealant - it WILL save weight AND stop punctures

[rojitor]

I"m going to add this to the faq .. lol...

You can not even imagine how many people ask that question, i have seen it on several forums. Btw as soon as you move this to faq i am sure pixar will increase "up" sales.

[Hardcarve1]

The same question is asked in kitesurfing and the answer is no as well.
Alex

[Sunder]

Pure nitrogen is sometimes used for better heat dispersion, and even pressures, which can very slightly improve efficiency at high speed. It's commonly been used n race cars and airplane tyres, but I think is a bit of a gimmick in normal cars, let alone ebikes. Maybe if you were a constant high speeder?

[Ypedal]

Nitrogen is supposed to remain constant at various temps..

[Hillhater]

Nitrogen is supposed to remain constant at various temps..

sorry YP, but that is not true.
All gasses behave in the same way with regards to pressure and temperature ( Boyles Law).
Any gas will increase in pressure when heated in a confined vessel.
The reason why nitrogen is used in tyres for race cars and aircraft is because it is almost completely uncontaminated with water vapour (which is in most compressed air).
Water vapour behaves very differently to a pure gas when heated.( more pressure increase)
Also nitrogen is inert, and cheap !

[heathyoung]

AND nitrogen is a much larger molecule than helium - your tyres would go flat every day - this is why they have those special foil balloons that stay inflated and floating for weeks versus 1 day for normal rubber balloons.

The only thing that would go flatter even faster would be hydrogen.

[TylerDurden]

When my tire guys ask if I want nitrogen, I tell them I already run a 78% blend.

[nechaus]

Yeah I was just looking at the periodic table..
something i should of figured out myself...
oh well

[Nehmo]

tyres/tubes with helium ?

That would be useless. However-
If you happen to be in an area where the wind is relatively constant, and it might be in Brisbane, Australia, and if you are travailing with the wind, and you don't exceed the vector-calculated speed of the wind, and you tether a helium filled (experiment for size) balloon so that the total height isn't enough to reach overhead obstacles (<4m), you would assist your forward movement as with a sail.
You could even use cheap hydrogen if you are careful about ignition. Then you can afford to deflate the balloon for trips opposing the wind.
Please report back with your results.

[wineboyrider]

Fill your tires with Red wine from Wineboy of course that way when your motor breaks down you can at least taps some off waiting for ride!

[Kin]

It's a sad truth, as a kid, that one only realizes what could be done with a 60lb lift weather balloon, once they themselves get older and weigh 90+pounds. (dear metric friends, 27kg and 41kg).

[The fingers]

An automotive tire guy told me that his nitrogen might freeze the inner tube in a bicycle tire and cause it to crack. True?

[Kin]

If you're talking liquid nitrogen, that can drop the temperature enough to crack rubber (not sure if it's about glass-transition temp, or if it's just how polymers generally become more brittle with lower temp.)

If you're talking about air nitrogen...Idk, i don't see how that should cause the rubber to crack. Air is already mostly nitrogen. For kicks, I just googled http://www.popularmechanics.com/cars/ho ... ns/4302788.

I somehow doubt this is all that important though.

[ThirtyFerretsInAManSuit]

The only thing that would go flatter even faster would be hydrogen.

Actually helium atoms are smaller than hydrogen molecules.

An automotive tire guy told me that his nitrogen might freeze the inner tube in a bicycle tire and cause it to crack. True?

This isn't to do with the temperature he keeps his nitrogen at, it's about the thermodynamics of the process of inflating the tyre. As the gas enters the tube, it does work on the side walls (pushing them out) which means the gas loses energy. The gas also probably would have been stored at a higher pressure than it would end up at once inside the tube - in this case as it expands its temperature would drop. Both these effects would make the nitrogen get colder as it is released into the tube.
Since polymers do indeed get more brittle with lower temperature, the risk of cracking the tube would be greater than normal. Polymers also tend to act more brittle the faster you change their shape; if the nitrogen is blasted in quite fast that risk is elevated further. And I imagine the machine your tyre guy uses is designed to inflate larger car tyres and might be automatic - so it really could blast the nitrogen in too fast.

[dnmun]

use bionitrogen in your tires!

[MikeFairbanks]

I saw online an article about a guy who (this is real) made a hot-air balloon using trash bags and was able to lift himself off the ground.

It wasn't a crazy thing at all. It was real, and I tried it myself when teaching.

The directions said to find the thinnest trash bags possible (black, of course) and then tape them together with the lightest tape possible (masking tape) and then let the sun heat it.

The ideal conditions are a cold, cold winter day with no wind but lots of direct sunlight. The temperature inside the bag will increase, the air will increase, and it will float.

Pretty cool science.

And kind of a waste of time and money.

I did it as a lesson, and on that particular day received a formal evaluation from a supervisor. The experiment failed miserably (I even tried using a hair dryer to get it started), but because I tried so hard and because our discussion was intense, I received a good evaluation.

[Dauntless]

use bionitrogen in your tires!

Fertilizer????

[beast775]

I cant get over stan the tire guy riding through that channel so many times .I would probably wipe out.

[rust]

Also nitrogen is inert, and cheap !

Nitrogen is FAR from being inert.

If it were, there would be no fertilizers, no nitrous oxide, no ammonia, no LIFE.