[skajumper]

Im sorry if this seems stupid but, why dont people put helium in their tires to save weight? or fill their shocks with helium. Or even, why dont manufacturers fill their frames with it. As far as i know, it wouldnt cause any forseeable problems. Just thought i would see what you guys think about this. Any possible dangers?

 

[skinny mike]

itll leak out of your tires pretty fast so it doesnt make sense to use it unless you like refilling your tires a couple times a ride.

 

[kinghami3]

helium leaks too fast, and hydrogen is explosive (it would be funny as hell to see some guys tires blow up though).

 

[BMXman]

plus the amount of weight savings is virtually undetectable by most riders...D

 

[Westy]

You could save more weight by pulling a vacuum inside your tires.

 

[binary visions]

You could save more weight by pulling a vacuum inside your tires.

I tried that but the cord wasn't long enough.

 

[Westy]

I tried that but the cord wasn't long enough.

Cordless, duh!

 

[blue]

Cordless, duh!

Is there a Presta adapter for my Dirt Devil?

 

[Westy]

Is there a Presta adapter for my Dirt Devil?

I made my own adapter with a rolled up dollar bill, some roof tar and a roll of electrical tape.

 

[MikeD]

The secret to using helium isn't to fill your frame or tires with it...it's to attach helium balloons to your heavy components. See, while a frame or tire is too heavy for the helium to lift them, the light ballons actually rise into the air...if you attach them to your bike, the kinetic energy transfers to the point of attachment, thus counteracting the force of gravity as it acts on the mass of the frame. Fishing swivels come in handy for this.

MD

 

[blue]

The secret to using helium isn't to fill your frame or tires with it...it's to attach helium balloons to your heavy components. See, while a frame or tire is too heavy for the helium to lift them, the light ballons actually rise into the air...if you attach them to your bike, the kinetic energy transfers to the point of attachment, thus counteracting the force of gravity as it acts on the mass of the frame. Fishing swivels come in handy for this.

MD

I was thinking of just mounting a shop-vac to my handlebars and using the suction to pull myself along a course/opponent. I haven't discovered a viable power source, but I have the feeling my fat guinea pig could be of use in this application.

 

[Westy]

I was thinking of just mounting a shop-vac to my handlebars and using the suction to pull myself along a course/opponent. I haven't discovered a viable power source, but I have the feeling my fat guinea pig could be of use in this application.

Leaf blower, decent thrust and it can be used to clear the trail of debris. You could also attatch some gas powered hedge trimmers to some vertically mounted bar ends to cut brush back from the trail.

 

[MtnbikeMike]

You can always attach model rocket engines to your bike for those finish line sprints....

 

[arboc!]

I was thinking of just mounting a shop-vac to my handlebars and using the suction to pull myself along a course/opponent. I haven't discovered a viable power source, but I have the feeling my fat guinea pig could be of use in this application.

i bet if you attatched a giant lightning rod to your bars you could get some power, or put carpet peices on your rims and a sock on your frame and run it on static power.

 

[The Misfit]

Rather than lightening the bike, I favor adding about 10 pounds to it for 30 days(ankle weights around the frame). On day 31 when the weights come off you will have increased your conditioning to the point where the bike feels 10 pounds lighter to you than it does right now.

 

[MikeD]

i bet if you attatched a giant lightning rod to your bars you could get some power,

1.21 Jiggiwatts, I believe. Enough to run the flux capacitor that Evil and Nicolai have been collaborating on...

 

[Skookum]

This thread is great, however getting back on subject why would Helium leak out of a tube any quicker than air. i've always been under the assumption that rotational wieght savings is key, and if you inflate tubes with helium you will accomplish that. Am i wrong in assuming that it might be more than what people are giving it credit for?

So it comes down to practicality and cost. Does helium actually leak from tubes deflating every few days? Does helium cost much, would it be difficult to buy cannisters to fill tubes.

Are people being to quick to dismiss the idea especially considering running 2.5 and 2.7 tires, where you would be subsituting heavy air for light gas.

Please spare me the fart jokes....

 

[LordOpie]

helium is a smaller element than 'air' (nitrogen, oxygen, etc). Rubber tires are so porous that you need to put regular air in them at least once a week. I've noticed that my tires don't stay as filled with CO2 over using aregular pump. Being more of a roadie who likes to pump up to 120-130psi, I don't think anything but regular air is viable.

Helium is about 1/3 the size of 'air'.

 

[Zutroy]

helium is a smaller element than 'air' (nitrogen, oxygen, etc). Rubber tires are so porous that you need to put regular air in them at least once a week. I've noticed that my tires don't stay as filled with CO2 over using aregular pump. Being more of a roadie who likes to pump up to 120-130psi, I don't think anything but regular air is viable.

Helium is about 1/3 the size of 'air'.

Straight nytrogen would work, but then you'd need to have a tank in your garage, which would be a bigger pain the pumping them would be.

 

[Wumpus]

helium is a smaller element than 'air' (nitrogen, oxygen, etc). Rubber tires are so porous that you need to put regular air in them at least once a week. I've noticed that my tires don't stay as filled with CO2 over using aregular pump.

I'll agree with the helium argument though I think it would last for a ride, but CO2 is a larger molecule than the main components of 'air' -- N2 = 28 and O2 = 32; CO2 = 44.

 

[splat]

Well you are both right about CO2 , it is a bigger molecule and Should maintain in your tubes longer , Bit it does not , but for a much different reason.

the problem is when you are putting CO2 into your tires it is from a 12 or 16 Gram Co2 cartridge, well it is cold , really really cold when it comes out ( see Boyles law of theremodynamics as to why ) and the rubber and metal in the tubes Valve get very cold. and the expansion coeificent of a rubber vs a metal are very different so what you are getting is your valve does not seal properly, because they are differnt sizes. It will probaly seal at the time , but when things get back to a Normal temperature , the changes will cause the valve not to have a perfect seal any more. Back when i worked at MIT working with the Liquid N2 we had to get special valves just to handle this very scenirio.

 

[Ian F]

Rather than lightening the bike, I favor adding about 10 pounds to it for 30 days(ankle weights around the frame). On day 31 when the weights come off you will have increased your conditioning to the point where the bike feels 10 pounds lighter to you than it does right now.

Or do most of your XC training on a 35 lb trail bike...

Helium in the tires...

 

[Wumpus]

Well you are both right about CO2 , it is a bigger molecule and Should maintain in your tubes longer , Bit it does not , but for a much different reason.

the problem is when you are putting CO2 into your tires it is from a 12 or 16 Gram Co2 cartridge, well it is cold , really really cold when it comes out ( see Boyles law of theremodynamics as to why ) and the rubber and metal in the tubes Valve get very cold. and the expansion coeificent of a rubber vs a metal are very different so what you are getting is your valve does not seal properly, because they are differnt sizes. It will probaly seal at the time , but when things get back to a Normal temperature , the changes will cause the valve not to have a perfect seal any more. Back when i worked at MIT working with the Liquid N2 we had to get special valves just to handle this very scenirio.

I figured it had something to do with the temperature, but didn't know what. So if you retighten your valves when you get done riding it should hold?

 

[splat]

I figured it had something to do with the temperature, but didn't know what. So if you retighten your valves when you get done riding it should hold?

It should. But I'd always forget actually you'd be best to tap the vavle to get it to reseat the whole way

 

[GravityFreakTJ]

molecule .......( see Boyles law of theremodynamics as to why ) .......... and the expansion coeificent of a rubber vs a metal are very different......... i worked at MIT working with the Liquid N2

cold drink of water would split my head wide open right now