# Helium Filled Tires



## GT Urban Warrior (Nov 6, 2005)

Hi There,

has any one pumped thier tires with helium gas? Did it make a difference in the bikes overall weight? How long did your tires stay pumped up?

Im curious coz here in Australia, many motor vehicles have their tires pumped up with helium to decrease their weight and save on fuel costs?

Cheers,


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## Low_Rider (Jan 15, 2004)

This has been asked a few times in various boards... 

Try these links:

http://forums.mtbr.com/showthread.php?t=137494&highlight=helium

http://forums.mtbr.com/showthread.php?t=20350&highlight=helium

http://forums.mtbr.com/showthread.php?t=41553&highlight=helium

Cheers.


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## gothrashers04 (Jan 4, 2006)

*Helium tires*

I filled mine up with helium once and i floated away! actually it seemed like a faster ride, but not as smooth


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## Flyfisherman (Jan 7, 2006)

I read through all of those links and this is the coolest thing I found:

"I've been talking to a guy in the research department of Nokian tires of Finnland, and he tells me, off the record, that they are experimenting with a new "rubber-type" compound that is essentially clear.....
They've been filling them with Neon gas and have found that the simple static electricity that is produced from rolling on trails or pavement produces enough power to make the wheels light up with a substantial glow...

Thus the product may soon be available for night riding.....for safety reasons it may become very popular. Glowing tires.... They tried it for auto tires but the casing is too thick to let the light through..

So glowing Neon tires are the next big development you'll be seeing....
And they roll real fast also like all Nokian tires..."


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## cmdrpiffle (May 8, 2004)

*Helium? soooo old skool*

Hydrogen !!! son, Hydrogen !!!!

Lighter than helium. Oz needs to catch up with the 21st century.

Cheers


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## PLURPIMPIN (Nov 3, 2005)

cmdrpiffle said:


> Hydrogen !!! son, Hydrogen !!!!
> 
> Lighter than helium. Oz needs to catch up with the 21st century.
> 
> Cheers


lol then your bike ends up like the hindenburg


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## PoweredbySweat (Jan 28, 2006)

PLURPIMPIN said:


> lol then your bike ends up like the hindenburg


I would think that all these gases would tend to leak more under pressure. The neon sounds interesting, but I'd have to see it to believe it.


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## cmdrpiffle (May 8, 2004)

*not entirely true....*

Yes some of the lighter gases would tend to leak obviously. I've had pretty good luck with some aftermarket sealants.

Stanzs Sealant is one of the better ones for helium. The do however warn against the use of either hydrogen or neon. Both of those gases leak appreciably faster. Stanzs warns that using either would void the warranty of their product.

That said, I know Jonny V Hempledirnt in Germany won the mens downhill using hydrogen in the front, and helium in the rear tires. Don't know if he was going tubeless, so I can't comment on if the Stanz woulda worked or not.

Cheers


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## @dam (Jan 28, 2004)

I just ran some rough numbers, and filling a 2.2" tire to 35 psi with helium instead of air would save about 12 grams per tire.


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## cmdrpiffle (May 8, 2004)

*cool*

@dams gonna get just a little high..............

"don't forget to bring a towel"


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## @dam (Jan 28, 2004)

they don't call me the smart-towel for nuthin'


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## djdub (Jan 12, 2006)

LOL...awesome.


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## Kaba Klaus (Jul 20, 2005)

The better way to reduce the weight of the bike is to deflate the tires. Bonus: no gas in the tires means less rotating mass and hence a faster acceleration!

That is the main reason DH champs run their tires with low pressure.


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## Low_Rider (Jan 15, 2004)

> The better way to reduce the weight of the bike is to deflate the tires. Bonus: no gas in the tires means less rotating mass and hence a faster acceleration!
> 
> That is the main reason DH champs run their tires with low pressure.


....


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## mtbgiovanny (Feb 13, 2006)

I'd say that if you put hellium into a bike tire you may explode in any minute put hydrogen that may work.
It's what they put into racing cars with nos so they don't flaten in any time.


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## nepbug (Sep 3, 2004)

All right let me put on my super-dork cap to respond to this one.

With Helium you will leak at a much higher rate than with any other gas. This is because it is a very small molecule and in gaseous form it is elemental (stands alone) and will fit through the smallest of pores. Hydrogen on the other hand has more lifting power than Helium and in gaseous form is found as H2 (has to team up with another Hydrogen molecule in order to be stable) so it is easier to seal up for Hydrogen. There is a little bit of worry because of the earlier post about static electricity in your tires, but remember in order to have combustion you have to have fuel and oxygen, so if the tire is filled entirely with Hydrogen there is no oxygen in there with it and it would be safe, but if you were leaking to the atmosphere and a spark happened you could have a nice flame shooting out of your tire, though Hydrogen fires tend to be invisible so you wouldn't see it (moral here, if your Hydrogen filled tire loses some pressure don't top it off with regular air as this would create an explosive environment in your tires). I'm in the aerospace industry and we do all of our leak testing of our components with helium because it will find the smallest of leaks. I've even seen helium leak through the wall of titanium tubing. 
Some quick numbers:
Air is 3% heavier than Nitrogen
Air is 43% heavier than Neon
Air is 724% heavier than Helium
Air is 1440% heavier than Hydrogen


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## HJB (Apr 27, 2004)

mtbgiovanny said:


> I'd say that if you put hellium into a bike tire you may explode in any minute put hydrogen that may work.
> It's what they put into racing cars with nos so they don't flaten in any time.


???

The tires on most race cars are filled with *nitrogen* primarily because nitrogen doesn't expand as much as compressed air when it heats up. As compressed air heats up the pressure goes up and the size of the tire grows changing the handling of the car. Nitrogen will expand but it's more predictable and controllable.


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## vapors2k (Mar 9, 2006)

HJB said:


> ???
> 
> The tires on most race cars are filled with *nitrogen* primarily because nitrogen doesn't expand as much as compressed air when it heats up. As compressed air heats up the pressure goes up and the size of the tire grows changing the handling of the car. Nitrogen will expand but it's more predictable and controllable.


And how much %nitrogen is in the atmosphere?

All gases expand with heat. There are fewer impurities when running nitrogen only gas (moisture aka water vapor) in tires when compared to air sourced from the atmosphere that may contain moisture and oils if used from an air compressor.

Interesting idea to run hydrogen in the tires though.


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## BoiseBoy (Mar 1, 2006)

Kaba Klaus said:


> The better way to reduce the weight of the bike is to deflate the tires. Bonus: no gas in the tires means less rotating mass and hence a faster acceleration!
> 
> That is the main reason DH champs run their tires with low pressure.


I think that you should open up your physics/chemistry 101 book again!
Deflating your tires and going fast has nothing to do with the "weight" of the air in your tires. This weight is so miniscule that you physically could not notice the difference in weight. The reason for airing down the tires is for traction and to help the suspension.


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## Low_Rider (Jan 15, 2004)

Let this thread go... please!!


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## cmdrpiffle (May 8, 2004)

*sorry Low Rider...just can't do it*

Boise Boy,

Not xactly. Lowering the air pressure does help with traction, but more importantly it reduces the volume of given mass. Air is comprised of Nitrogen, Oxygen, Carbon Dioxide, and the infamous....'other'. 
Downhillers have learned that if they skip the previous 3, and just fill their tires with tiny amounts of the 'other gases', their rotating mass is kept to an absolute minimum, while increasing traction due to lower overall pressure.

Cheers

Cmdr ' gassy' Piffle, PhD.


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## Bluegroove224 (Jan 13, 2006)

Nascar has been running Nitrogen in their tires for years. Doesn't have the condensation that air has so no change in pressure with temp change, better gas mileage etc,etc.


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## Down boy down (Mar 2, 2006)

*Tongue in Geek*

How about Ununoctium


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## @dam (Jan 28, 2004)

HJB said:


> ???
> 
> The tires on most race cars are filled with *nitrogen* primarily because nitrogen doesn't expand as much as compressed air when it heats up. As compressed air heats up the pressure goes up and the size of the tire grows changing the handling of the car. Nitrogen will expand but it's more predictable and controllable.


I don't think so. PV=nRT


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## HJB (Apr 27, 2004)

@dam said:


> I don't think so. PV=nRT


Ok ya lost me there. I'm no scientist, just giong on what I'm told.

Care to elaborate?


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## demo_slug (Jan 1, 2005)

HJB said:


> Ok ya lost me there. I'm no scientist, just giong on what I'm told.
> 
> Care to elaborate?


PV=NRT is the ideal gas law. its generally taught in high school and chem 101.

It relates pressure to temperature to volume to moles of gas. and is gas independent. any expansion of the gas due to temp. will be very close to the same, from gas to gas.

air is mostly nitrogen.

I think they use it because its clean. you don't have to worry about getting contaminated air with water vapor or oil from billy joe bobs compressor. they probably use three 9s N2 ( 99.999 % pure).

the thermal conductivity would be more stable from fill up to fill up. which is going to help spread the heat more consistently from fill to fill.

and there is no oxygen which is an oxidizer.

and I think the leak rate is going to be more stable.


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## switch55 (Feb 17, 2006)

I never learned any of this in College chem 101, but then again there was this girl that sat in front of me that was always wearing a thong and ................................ 
But somehow I still passed.


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## uktrailmonster (Oct 10, 2004)

Racing cars often use nitrogen in their tyres to prevent unpredictable pressure variation with temperature, due to unknown moisture content (as some others have mentioned). There is still pressure change with temperature, but very predictable using a pure dry gas. Actually in Formula 1 we now simply use "dry air" pumped through special de-humidifying compressors. Other gases are sometimes used (with varying thermal properties) which I can't talk about here!

Weight differences between different gases have no effect I've ever measured. Pressure and temperature are by far the main performance parameters.


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## GuruAtma (May 17, 2004)

I saw a show on TV talking about putting nitrogen in regular car tires. The benefit was that nitrogen, being a bigger molecule, wouldn't leak as fast as regular air. A big reason people get poor gas mileage is that their tires are under-inflated. So with nitrogen your tire stays at the proper pressure longer.


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## DamoNNomaD (Apr 7, 2006)

Fill your bike tires with ass gas for all I care. NONE of it makes ANY difference.


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## jonawebb (Sep 8, 2008)

*Helium Filled Tires, the math*

The math is not difficult and gives a savings of over 9 g/tire. Since this is rotational weight at the tire edge it is enough to make a noticeable difference and should be considered in situations where the necessary equipment could be made available.
Here's the calculation:
For a 28 mm width tire the cross-sectional area is r^2 * pi = 14*14*pi = 616 mm^2.
If the wheel diameter is 700 mm the volume will be C*A = 2 * 350 * pi * 616 = 1,350,000 mm^2 or 1.35 l.
Now, air at standard pressure weighs about 1 kg/m^2 or 1 g/l.
Air pressure in a tire is about 8 times standard pressure so the air would weigh 8 g/l. So you have 8*1.35 = 10.8 g of air in each tire.
A mole (4 g) of helium has a volume of 22.7 l at standard pressure. That is 4 g/22.7 l = 0.176 g/l. 
At tire pressure that would be 8*0.176 = 1.40 g.
The difference, then is 10.8 g - 1.40 g which is more than 9 g.


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## cmdrpiffle (May 8, 2004)

*Thanks Dr. Frankenstein*

Teh thread........it LIVES! IT'S ALIVE !!!


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## Garlock (Jul 9, 2008)

Why would ou bump this?

What concerns me is the compressing properties of the gas in question. You might fill the tyres to an ammount, bt once you get on the bike, they might compress too much, needing more air pressure, which would make them heavier, which would eliminate the advantage.
Random thoughts. Also, why bump this?


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## TiCN WC (Sep 6, 2008)

The primary concern with air is the moisture content. 

As temperatures change the number of moles of gaseous water vapor change making predicted pressure changes impossible to predict without knowing the relative humidity of the air in the tire at a given temperature and pressure. This is hard to know and is another thing to account for. It is far easier to take this variable out of the equation by using a dry gas. 

What really strikes me as crazy is using regular humid air from shock pumps instead of nitrogen tanks for air bicycle shocks. 
Using nitrogen would be quite advantageous in such an application as there are large fluctuation's in temperature in all dampening systems to account for. as well as internal parts and seals that moisture can attack. 

Argon is also an acceptable gas to use if you don't have Nitrogen (but more expensive)


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## Garlock (Jul 9, 2008)

5char


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## XCProphet (Aug 23, 2005)

*Let's Not Forget..*

..tires with less air create more surface area to grip trail, thus less acceleration slips from weight transfer through wheels,


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## rabidweasel999 (Oct 22, 2006)

Put DH tubes filled with helium on a DJ/urban bike and your jumps will improve!


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## nnn (Feb 1, 2005)

Lol did someone just write that Nitrogen doesn't obey the most basic equation of state 

The reason racing cars use nitrogen is not that it doesn't expand (now that WOULD be something) but it expands predictably in a linear manner, because it's pure. Atmospheric air is a mixture of other stuff including water vapour and expands unpredictably with temperature. Why pure nitrogen ? Easiest gas to purify to a sufficient degree I'm guessing.


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## colby13r (Aug 23, 2008)

air, what we breathe is 78% Nitrogen, and 21% Oxygen. The other 1% is a dozen or more different gasses. Helium molecules are smaller than those of any other gas in existance except for Hydrogen, which is flammable. Pure Nitrogen is a bit lighter than Pure oxygen, but not by much. technically, most pure gasses you fill your tires with will make your bike lighter than if you use a hand pump or compressor that just uses air. Air is extremely heavy compared to most gasses. filling your tires from a scuba tank would be a great idea if you can get a regulator to slow the flow down. Scuba tanks have either Nitrogen or Oxygen in them.


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## DHHogan (Jul 28, 2008)

*Gases in Tires*

I worked for an airline, in the Maintenance Division, for 37 years. The airline industry used Nitrogen in the tires because it was an inert gas. Lighter than air was NOT part of the consideration. How much lift can you get from the small volume in a bicycle tire?

_________________________
Oldman with a Reign 1


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## Hawseman (Jun 1, 2007)

I fill my Camelback with helium gas....when I endo, I just let go of the bars and float safely to the ground. It's also very funny when I take a big swig and yell at my riding mates in a Mickey Mouse voice.....course, I get pretty thirsty, but it's well worth it.

I've been thinking about filling my tires with mercury....for the downhill rides, of course. I imagine that I could plow pretty good with those puppies. I'd be worried about busting a sidewall, cause I'd have to call a HAZMAT team to contain the spill.....probably get in trouble, too.


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## colby13r (Aug 23, 2008)

nitrogen is not an inert gas. its not very reactive, but it is not by any means, inert.


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## Wheelspeed (Jan 12, 2006)

jonawebb said:


> The math is not difficult and gives a savings of over 9 g/tire. Since this is rotational weight at the tire edge it is enough to make a noticeable difference and should be considered in situations where the necessary equipment could be made available.
> Here's the calculation:
> For a 28 mm width tire the cross-sectional area is r^2 * pi = 14*14*pi = 616 mm^2.
> If the wheel diameter is 700 mm the volume will be C*A = 2 * 350 * pi * 616 = 1,350,000 mm^2 or 1.35 l.
> ...


Oh, then don't forget the 40g of sealant you have to add to keep such a small molecule from leaching out.


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## demo_slug (Jan 1, 2005)

colby13r said:


> nitrogen is not an inert gas. its not very reactive, but it is not by any means, inert.


just thought I would add to the super old dead post. 

N2. its diatomic. if you want inert use a noble gas like argon. :thumbsup:


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## tech_dog (Aug 25, 2008)

Since the air is free to move rotationally around the rim and tire, the air has much less impact on the rotational inertia than what would be calculated based on mass alone.


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## colby13r (Aug 23, 2008)

argon is a bit expensive. n2 is lighter than o2, but people dont fill their tires with pure o2. so just go get some pure nitrogen from a dive shop, or you can get a multitude of different types of gasses from a welding supply store.


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## Wheelspeed (Jan 12, 2006)

*Order of threads?*

I have a more important questions...

Why do the responses get mixed up, time-wise?

I made a response recently here (it says "20 hours ago" now as I write this), and it's mixed up in the responses from "4 weeks ago".

This happens all the time on MTBR. What gives?


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## emtnate (Feb 9, 2008)

colby13r, do you dive? I don't, close family members do, I have been through dive classes, and SCUBA is very similar to the SCBA we wear while putting out fires.

SCUBA contains neither pure nitrogen nor pure oxygen. Pure nitrogen would be lethal, as the body requires O2 for cellular function. Pure oxygen would be dangerous. Standard SCUBA contains nothing more than compressed air from wherever their cascade system and compressor resides. Surrounding air quality to the compressor is important. 

Nitrox branded mixes contain a lower proportion of nitrogen to oxygen than regular air. This is to reduce the chances of decompression illness. There's also blends containing helium whose intent is to reduce the risk of nitrogen narcosis.


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## XJaredX (Apr 17, 2006)

8 months ago I bought new tires for my Subaru and I had them put nitrogen in them when they were mounted.

I have yet to have to put more nitrogen or air in them. They literally have not lost any pressure in 8 months. Also, PSI when cold is damn near the same as PSI when the tires are warmed up.

I'm no physics genius but take that for what it's worth


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## ash240 (Jun 2, 2007)

XJaredX said:


> They literally have not lost any pressure in 8 months. Also, PSI when cold is damn near the same as PSI when the tires are warmed up.


How do you check? You can't put a gauge on without some loss.


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## KINBOY (May 23, 2004)

Wheelspeed said:


> I have a more important questions...
> 
> Why do the responses get mixed up, time-wise?
> 
> ...


It depends on the response method I think. If its a quick reply it just throws it at the bottom, if you are hitting a reply button it replies to that post and places it there. 
I think so at least but have noticed that. 
Also....the different views...who uses them..

KIN


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## essenmeinstuff (Sep 4, 2007)

the best thing is to build up a rigid donut shaped carbon lattice that is firm yet flexible, and fill it up with vacuum. Vacuum is the best in tires because it weighs NOTHING! Thats an infinite percent weight saving over using air!!!


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## finger51 (Jul 21, 2006)

nepbug said:


> All right let me put on my super-dork cap to respond to this one.
> 
> With Helium you will leak at a much higher rate than with any other gas. This is because it is a very small molecule and ...


I just had to stop reading right there. Tell us more about this molecule called helium Mr. Wizard!!!

LOL +1


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## finger51 (Jul 21, 2006)

essenmeinstuff said:


> the best thing is to build up a rigid donut shaped carbon lattice that is firm yet flexible, and fill it up with vacuum. Vacuum is the best in tires because it weighs NOTHING! Thats an infinite percent weight saving over using air!!!


How do you 'fill' something with a vacuum? Man! this thread is chock full o' fail.


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## tech_dog (Aug 25, 2008)

essenmeinstuff said:


> the best thing is to build up a rigid donut shaped carbon lattice that is firm yet flexible, and fill it up with vacuum. Vacuum is the best in tires because it weighs NOTHING! Thats an infinite percent weight saving over using air!!!


Even the carbon lattice seems like a compromise. What you really need is superconductor based magnetic levitation. This could eliminate the need for heavy suspension parts, brakes, wheels, and hubs.

Assuming high quality room temperature superconductors, very little power would be required, allowing for a light weight battery or solar cell.


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## essenmeinstuff (Sep 4, 2007)

finger51 said:


> How do you 'fill' something with a vacuum? Man! this thread is chock full o' fail.


failure to see the funny?


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## finger51 (Jul 21, 2006)

essenmeinstuff said:


> failure to see the funny?


Yeah, I guess my snark-o-meter was in the wash that day. heh.


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## leshaghal (Mar 10, 2011)

*The FACTS*

Car tires are filled with nitrogen because in a month an air filled tire can lose anywhere from 1-2 psi, let a few months elapse and before you know it your bleeding MPG. Race cars use dry air or Nitrogen for consistent and predictable expansion rates. (shocks also use nitrogen and dry air for much the same reason, plus nitrogen helps reduce the foaming in oil. this is why it's used in most shock applications)

An all oxygen filled tire would most likely burst into flame! Under pure oxygen the ignition temp of any fuel source drops significantly...sometimes below ambient temp which leads to spontaneous combustion. The oil from your skin at room temp will ignite under pure O2, Google Apollo 1 (there's a lot of welder's parlor magic that exploits this property)

Argon.....what for? I've seen a trials tire filled off a welder in pinch but I wouldn't call it a performance upgrade.

Helium and hydrogen....what a load. YES you will save weight...in theory... but I've got an easier way!!! the easiest. it's cheaper, more convenient, and will save you a TON.

Drop a deuce before you ride!!!! you'll shave at least a lb off your sprung weight!!!
lose all that weight and all for free..the gains are HUGE compared to helium tires and carbon chainlinks!

I'll tell you the same thing I tell my little (well not so much anymore) Brother,

"It's the Indian not the arrow!"

he's 50lb lighter than me which make shim more nimble. he's been a better rider since we were kids, and always will be. I've got triple the time on a bike but with me at 6'2/ 214lb he'll always have a better power to weight ratio.

So forget about helium in your tires and carbon sprockets and go shave a few grams off the rider! You'll feel better, ride better, look better, and as a result of all the aforementioned, Get more ass!:thumbsup:

And thats better than helium any day!


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## Mountain Cycle Shawn (Jan 19, 2004)

Wouldn't you need two stems to purge all the air out.


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## TyranT (Mar 30, 2011)

I've heard of BMX frames being filled with helium and apparently made a big difference and it doesn't leak at all.


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## leshaghal (Mar 10, 2011)

I've heard of the BMX frames as well, helium is small enough to bleed through the tubing wall on a standard bike frame (provided it couldn't run out through the drain holes first) have a gander at this from Ridemag apr. 2006

"Helium is about a seventh the density of air. So yes you can make a massive *percentage* saving on the weight of the air in your tyres. However the air in your tyres probably only weighs about 34g, or 1.2 ounces (based on two twenty inch tyres, two inches wide and 75psi).So by switching to Helium we would save just 29g (about an ounce). 
Helium is totally inert, it doesn't form any bonds so we aren't dealing with a 'helium molecule' we are dealing with individual atoms of helium, and atoms are what we-in-the-trade call "very small". In this case, so small that they don't have much of a problem wriggling their way through the actual rubber of the inner tube, and f-king off to outer-space as is their nature. So, in much the same way that you need a fancy metallic balloon, you would need fancy inner-tubes to keep that precious helium in your tyres for more than just a few days"

To summarize; 22x2" [email protected] 75 psi, helium provides an 85% weight saving=29g/1.022 oz

A T-shirt 
On average weighs:
Small: 6 oz.
Medium: 6.5 oz
Large: 7 oz
X-Large 7.50
2X-Large 8.75
3X-Large 9.50

So you'd save more weight by riding shirtless!!!

better yet; go on a diet, shave your body, slap on a speedo, and vomit before you ride. Once you're riding THAT light Then you should look at pulling a vacuum on your frame and filling your tires with helium.

long and the short of it,You're looking down the wrong alley on this one.


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## cmdrpiffle (May 8, 2004)

*Obligatory every 3 year post*

Teh thread........it LIVES! IT'S ALIVE !!!

repeat ad. nauseaum


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## raganwald (Mar 1, 2011)

cmdrpiffle said:


> Teh thread........it LIVES! IT'S ALIVE !!!


And it mutates off-topic!!!

Did you know that the very same properties of Helium that allow it to escape through the inner tube also make it a "fast gas" for scuba divers? So when breathing a mixture of Oxygen and Helium instead of Oxygen and Nitrogen (standard air), on the return to the surface you have to stop more often to off-gas the helium than you would if you were breathing standard air.


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## zahgurim (Aug 12, 2005)

You don't get nitro-narced off of He, which is why it's used for longer/deeper dives.


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## raganwald (Mar 1, 2011)

zahgurim said:


> You don't get nitro-narced off of He, which is why it's used for longer/deeper dives.


Correct! Although I really wasn't trying to derail the conversation as much as make a joke about old topics and their propensity for meandering off topic.

But since you mention mixed gas diving, some folks believe that Oxygen is also narcotic. I calculate equivalent narcotic depths (END) on that basis myself. I don't know for sure, it it's a more conservative calculation than presuming that narcosis is only created by the nitrogen. The difference comes into play when diving mixtures like 25/25 or 30/30.


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## kmorast (Jul 20, 2009)

I work in the airline business, another reason we use Nitrogen in aircraft tires because it is non-flammable and won't make a brake fire worse if a tire explodes.


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## Sanction (Apr 2, 2011)

Flyfisherman said:


> I read through all of those links and this is the coolest thing I found:
> 
> "I've been talking to a guy in the research department of Nokian tires of Finnland, and he tells me, off the record, that they are experimenting with a new "rubber-type" compound that is essentially clear.....
> They've been filling them with Neon gas and have found that the simple static electricity that is produced from rolling on trails or pavement produces enough power to make the wheels light up with a substantial glow...
> ...


Lets go Nokian, its been 5 and a half years now and Im still waiting to do some night riding on these.


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## Your Bike Sucks (May 20, 2011)

> You don't get nitro-narced off of He, which is why it's used for longer/deeper dives.


While it is true you won't narc out on Helium, that's not the only reason why we dive it.

We can stay down longer at the same depths on Helium/O2 than on just compressed air. It takes longer to absorb Helium in the tissues than Nitrogen. It does take longer to decompress once you've passed the tables on Helium than on Nitrogen, though.

300 feet is how deep we can go on Helium/O2....silent, undetected, non-magnetic, alone, in the dark, in the middle of a minefield...get some, lol  .

Hooyah Navy!!


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## Your Bike Sucks (May 20, 2011)

And, oh yeah, helium in mountain bike tires?

Bahahahahahahahahahahahahahahahahahaha    .


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## raganwald (Mar 1, 2011)

Your Bike Sucks said:


> We can stay down longer at the same depths on Helium/O2 than on just compressed air.


What do you mean by "stay longer?" People have stayed for weeks underwater on various mixtures. Do you mean "stay longer without formal decompression?" If so, what methodology are you using to calculate your "No Decompression Limit" and can you give an example depth and compare the times you get for NDL on air vs. He mix?



Your Bike Sucks said:


> It takes longer to absorb Helium in the tissues than Nitrogen.


This statement says the _opposite_ of what I was trained to believe when being certified to use He, so be careful what you read about diving on the internet, especially if it's on a MTB forum.



Your Bike Sucks said:


> It does take longer to decompress once you've passed the tables on Helium than on Nitrogen, though.


Again, what's your methodology? I was trained to treat He as a fast gas, which means it takes less time to off-gas it in a certain sense, but makes it easier to get bent on it in another sense, which leads some methodologists to proscribe a differently shaped deco profile. I don't know any methodology that dictates the same stops but simply lengthens them for He.



Your Bike Sucks said:


> 300 feet is how deep we can go on Helium/O2


A simple Google search will reveal that many divers have gone below one hundred metres on He. As I haven't been trained for this type of technical diving, that is all I'll say.


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## Your Bike Sucks (May 20, 2011)

Yep, our tables (US Navy) are different than civilian tables for diving. Our Helium tables are different than our Nitrogen tables. 

Where do I get my methodology? The United States Navy, of course.

I spent 9 years as a US Navy E.O.D. Diver. We use Helium/O2 in our re-breathers when going deep...pure O2 if swimming just under the surface...no bubbles, no troubles  .


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## rckygrrl (Mar 19, 2011)

Snip!


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