Helium filled tires

Hey! You’ve lost half your molecules!

One thing:

Even if helium did somehow make an appreciable difference in the performance of unicycles, would anyone use it? I would much rather get an improvement in riding through practice than wasting money on equipment.

Mikefule: Funny story about storing hydrogen in a polythylene bag. Reminds me of what one of my physics professors once told me. “I found that ziplock bags make excellent storage containers for antimatter.” Of course “excellent” is a relative statement here, being as he is talking on a timescale of milliseconds. However, he was correct, from what I understand. The static charge of the bag offers enough of a repulsion force that it takes the antimatter unusually long to encounter something to interact with. Jason, if you read this, did Dave ever tell you that one?

A slightly more practical application of gas laws: On drilled rims, the holes effectively increase the surface area of the innertube, giving slightly more spring. However, the force applied to various parts of the rim strip is not even. On my trials uni, which runs a Try-All rim, the holes directly above my favored hopping are have large bulges in the rim strip, because of compression from hops. On area 90* from there, I find virtually no bulge. A gas with a lower viscosity would presumably carry the force of the hop more evenly around the wheel, giving different spring characteristics for the same pressures.

I would much rather do both

The thing with nitrogen in the tires has been explained to me as that nitrogen doesn’t contain the moisture that is in ‘regular’ air. If you own an air compressor without a water filter, you know what I mean. With less moisture in the air, it’s more stable as it heats and cools as far as pressure goes.

Also, so I’m told, nitrogen molecules are larger, so less prone to leaking through the valve seals, tire beads and even the rubber itself.

For whatever the scientific reason, I have seen with my own eyes and measured with my own air pressure guage. When you bring a racecar off the track with nitrogen in the tires, they have not ‘grown’ as much as plain air after heating up. Also, the temps we’re talking about are much higher than most people see on their street cars. Even coming off of damp clay, we will measure 150-200 degrees F. Pavement racers will see much higher than that, so the difference between hot and cold and the expansion issues caused by it are magnified.

It’s not just F1 cars that run nitrogen. We were running it at our podunk little 1/4 mile dirt track years ago. And many decent tire shops are now giving consumers the option to run it on their street cars. They even put cute little green valve stem caps on so service people know that they are nitrogen filled. Though in that case it’s usually based on the idea that they don’t lose pressure as fast so don’t need to be filled as often. Most drivers can’t tell a difference of 10 pounds of air, much less the difference between hot and cold pressure changes.

Wow… that got way longer than I intended haha…

That’s interesting. Air’s around 79% nitrogen anyway, so changing the 21% to nitrogen makes a noticeable difference? They think of everything these days.

hydrogen would be the best but it would only stay in the tube very short. Using helium would make a weight difference but it is the same like using carbon stuff its expensive and does not help much. Rather take a good shit before trials, its lots cheaper and does the same thing:) :slight_smile: :slight_smile:

[QUOTE=gerblefranklin]
One thing:

Mikefule: Funny story about storing hydrogen in a polythylene bag. Reminds me of what one of my physics professors once told me. “I found that ziplock bags make excellent storage containers for antimatter.” Of course “excellent” is a relative statement here, being as he is talking on a timescale of milliseconds. However, he was correct, from what I understand. The static charge of the bag offers enough of a repulsion force that it takes the antimatter unusually long to encounter something to interact with. Jason, if you read this, did Dave ever tell you that one?
QUOTE]

Just having a minor brainstorm in trying to imagine how to generate a vacuum inside a ziplock bag, good enough to give the antimatter so little to react with, that the static has any chance at all to have an effect on its longevity.

Nao

[QUOTE=gollum89]
like using carbon stuff its expensive and does not help much.

[QUOTE]

carbon fibre’s major benefits are in it’s strength and rigidity, and it helps signifigantly

In some circumstances.

In others, its main advantage is the credibility it gives to the owner.

In motorcycling, it is possible to buy sheets of self-adhesive carbon fibre to put on your bike to make it look lighter. Most motorcyclists are overweight.

Saving weight on a uni: important in this order
Tyre
Tube
Rim
Rider
Spokes
Pedals
Cranks
Seat
Seat post
Frame
Hub

put rider just below tyre!! then its right

I’m trying to remember how many threads I’ve read where people are asking, “what’s the best trick to impress non-unicyclists?”

My kingdom for a BB gun.:smiley:

LOL!

Hooked

If the Chihuahua would land on top op you, you would do credit to your name.

Hadn’t thought of that.:wink:

Hmm, I didn’t think about that when he told me. The simple soluition I have is to put the entire bag in a vacuum chamber. If you make enough antimatter, obviously some will end up reacting, but there should be some left over aswell. Of course, I didn’t do the experiment, so I’m sure I’m leaving plenty out.