FWD: Helium in tyre...

The helium question was addressed a few years ago by a British unicyclist, and it’s still one of my favorite postings. He presented a complex mathematical formula that showed how to measure the benefit of helium gas over air in a unicycle tire. His summa
ry: though there was reduction in weight, it was minimal. The net effect would be equal to riding without socks.

-John

---------- Original Message ----------------------------------
From: andrew_carter <andrew_carter.nltzm@timelimit.unicyclist.com>
Date: Sat, 17 May 2003 22:10:55 -0500

What volume of air do you think would be in the average Gazz 24" x 3"?
Or more to the point (and saving me a lot of thaught and time :)), how
much lighter would a unicycle be that’s fitted with a Gazz filled with
helium? Is helium the lightest available gas?

What if you made a uni that had some sort of really light gas in the
tyre, frame, cranks, and seat?

Andrew

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Thanks John, it’s a fun thought all the same though isn’t it. I’m glad you added that bit about the socks…it really puts thing in perspective.

Andrew

Helium is a very interesting substance. It is the first in a series of Noble Gases, also known as monatomic gases.
The molecular weight is a little more than 4, meaning one mole of gas has a mass of about 4 grams. A mole occupies around 22.4 liters at STP.

Helium is the most volatile liquid known, boiling at 4.215K. For example, the melting point of molecular hydrogen is 13.96K at it’s triple point at 54mm pressure.

But molecular hydrogen (H2) has a molecular weight of only 2, about half of helium. If the goal is weight reduction, hydrogen would do best.

A mole of air is going to be close to 14.4 grams.

i prefer to ride on nitrous…

I’ve just installed a little button on my handle which, when pushed, provides a huge boost of power and allows me to go uphills at phenomonal speed…

Mr. IUnicycle, you’re starting to sound like Mr. Harper!

I’m was considering Helium for when I get my carbon-fiber air seat, now its Hydrogen for sure. And riding without socks, the static may present a shock and explosion hazard with the Hydrogen.

I need NOS!!!

Didn’t you mean ‘blah, blah, blah…’?

I’m not sure exactly what this means, but the relative lifting power of helium is 93% that of hydrogen. But I don’t think you really get much lift from pressurized gases, until you release them…