Should I pump my bicycle with helium?

I was pumping my bicycle tire the other day when I came to think of how much energy I would save if I used helium instead of air whilst biking. I decided to work it out.


The idea here is that you need to figure out what volume of gas held at STP conditions is needed in order for the tire to have a volume of 1.35 L at 8.5 atm and 20.0∘C.

Since pressure, temperature, and volume change, you can use the combined gas law equation to find the volume of gas at STP.

The combined gas law equation looks like this:
P1V1/T1 = P2V2/T2, where P1V1T1 = the pressure, volume, and absolute temperature of the gas at an initial state
and P2V2/T2 the pressure, volume, and absolute temperature of a gas at a final state.

So, STP conditions are defined as a pressure of 100 kPa and a temperature of 0∘C. To convert the pressure to atm and the temperature to Kelvin, use the conversion factors.

1 atm = 101.325 kPa

T[K]=t[∘C]+273.15

You're starting with the gas under STP conditions, then changing its temperature to 20.0∘C and its pressure to 8.5 atm.

Rearrange the combined gas law equation to solve for V1

P1V1T1=P2V2T2⇒V1=P2P1⋅T1T2⋅V2

Plug in your values to get:

8.5 atm/(100/101.325 atm) *(273.15K + 0) K / (273.15 + 20.0) K * 1.35 L = V1 = 10.834 L, which we round up to 11 L.

1 m^3 ofweighs 1.3 kg, therefore 1 litre of air weighs 1.3g ==> 1 dm^3 = 1 l = 1 m^3/1000

1.3g * 22 = 28,6 g

1 m^3 of helium weighs 0.1785 kg, therefore 1 litre of helium weighs 0.1785 g -II-

0.1785 * 22 = 3,927 g

28,6 - 3,927 * 10^-3 = 0.024673 kg

0.024673 kg * 9.82 = 0,24228886 N

I bike 3 km everyday. Let's see how much I'd save biking a whole year.

W = F * s

3000 * 0,24228886 N = 726,9 J
726,9 J * 365 = 265 kJ

In conclusion: I'd save 265 thousand Joule if I were to use helium instead of air in my tires. This is of course a rough estimate.

What do you guys say? Should I start using helium in stead of air?

 

LOL but helium aint good for like for ever? u have to change every few days or am i wrong?

 

Don't think so. A source on this would be nice.

 

Yes he has to refill every few days.

Are you considering the fact that helium molecules have a significantly lower atomic mass than a regular air molecule and would result in your tires leaking super fast?

This is why some people decide to use Nitrogen over Helium in their car tires for fuel efficiency.

 

My head hurts. Just pump your bike with regular air like 99.9% of normal people do lol

 

But that's no fun

 

Pump ur car weels with helium

 

Hell yea you should. Then try to ride off a tall building so you float away

 

What did I ever do to you?

 

bump

 

wow!

 

Yes

 

i mean if you want to fill your bike with helium it should be ok? I think you just wanted to show off some basic math though.

Anyways why are you saying "bump" on a thread when it's already at the top of General Discussion? I mean i know you gotta get your post count up somehow but still lmao

 

Must've confused it with some other thread while doing my daily bumps

 

Nothing? if it works I wanna know so I can try?

 

You'll reduce the bike's weight a negligible amount, but go for it if you have access to it I guess. Helium doesn't go bad. Balloons only deflate because the helium leaks out.

 

I think it'd take more effort to purchase the helium and so on than the energy I'd save. I think I'll pass.

 

It'd be more efficient for you to attach a small motor system to assist in pedalling.

 

That's expensive and time consuming :-/

 

do it just do it