Pressure loss in tubed tyres with CO2

[cyberknight]

Agree with using it as a get you home but i dont deflate , just top it up , i check my tyre pressures weekly on my commuter and even with c02 in its ok the restof the week.
Another option is a mini track pump ,so you can pump it up quickly out and about and at home as long as you dont mind carrying a medium sized pump.
http://www.wiggle.co.uk/topeak-moun...14uk&pgrid=17507340062&ptaid=pla-121263966062

 

[palinurus]

CO2 is for getting you home after a puncture. It leaks because (I think!) has smaller molecules so escapes from the rubber tube.

CO2 molecules are larger than N2 molecules (that make up the bulk of air), but CO2 is more soluble in butyl rubber and diffuses through it at a much faster rate (very approximately 15 times faster)

Here's a nice chart- X is measure of size, Y of permeability through a rubber membrane.

Generally increasing size does lead to reduced permeability but the effect of increased solubility for CO2 is much larger.

Anyway, yeah- top it up with air once you get home.

 

[Paulus]

Agree with using it as a get you home but i dont deflate , just top it up , i check my tyre pressures weekly on my commuter and even with c02 in its ok the restof the week.
Another option is a mini track pump ,so you can pump it up quickly out and about and at home as long as you dont mind carrying a medium sized pump.
http://www.wiggle.co.uk/topeak-mountain-morph-pump/?lang=en&curr=GBP&dest=1&sku=720708814&kpid=720708814&utm_source=google&utm_term&utm_campaign=UK_PLA_Accessories&utm_medium=base&utm_content=mckv|sfpJ8C8JJ_dc|mcrid|67090793462|mkw||mmt||mrd|720708814uk|mslid||&mkwid=sfpJ8C8JJ_dc&pcrid=67090793462&prd=720708814uk&pgrid=17507340062&ptaid=pla-121263966062

I have a Mini Morph road pump and it is very good. Gets up to 100psi easily. It is also quite light and fits into your back pocket.

 

[andrew_s]

Why use CO2 air that cost money when a simple bike mounted pump uses free air?

People use CO2 because most modern pumps are slow, or very slow.

Proper frame fit pumps, which were universal back when all frames were steel, don't fit most modern bikes well, what with sloping top tubes, the lack of pump fittings, hydroformed aluminium, and carbon of any old shape. For most people, it's either a mini pump in a back pocket, or a slightly less mini pump in a clip under a bottle cage.
Mini pumps don't work well by comparison - they'll take a lot longer to get to a 100 psi riding pressure, if they get there at all.

The best are the mini track pumps, the best of which are about as good as a smaller frame fit pump. I'd take it that if a rider is carrying one of these, he's not using CO2.

 

[boydj]

I'm an odd duck on this one, fine, I'm just plain odd, anywho, I don't advocate CO2 unless your racing otherwise you don't need it. Why use CO2 air that cost money when a simple bike mounted pump uses free air? Why go through the effort of filling a tube with CO2 only to go home and drain all the air out and fill with a pump? that's twice the work. Why dispose of unnecessary waste? Of course when it comes to throwing those carts out you can do what a lot of CO2 users do and that is simply throw it discreetly along side the road...

If you are on a group ride, normally the group will stop if someone has a problem. CO2 helps get everybody moving again with minimal delay. With the small pumps carried by most roadies these days it's hard work getting a tyre up to a reasonably high pressure. The used CO2 canister and the duff tube are taken home to go into the recycling - leave the countryside as you find it.

 

[Alan O]

Proper frame fit pumps, which were universal back when all frames were steel, don't fit most modern bikes well, what with sloping top tubes, the lack of pump fittings, hydroformed aluminium, and carbon of any old shape.

Ah, the answer to a question I've been meaning to ask - thanks

 

[cyberknight]

And weight weenie ism

 

[iluvmybike]

[QUOTE 5107295, member: 9609"]I don't think the tubes can be recycled so if you put them into the recycle bin they will just go to land fill, what a waste! - they are usually very simple to repair.

Just because it is possible to recycle the co2 container does not mean it is an environmentally friendly thing to do. Melting down then reforming metal uses a lot of energy, energy that usually comes from fossil fuels and adds to climate change. There is nothing environmentally friendly about it, esp when the whole concept of these canisters is based on laziness. If someone can cycle 30 or 40 mile they have the energy to blow a tyre up with a pump.[/QUOTE]
On that basis then having a bicycle isn't very environmentally friendly then!!

 

[boydj]

[QUOTE 5107295, member: 9609"]I don't think the tubes can be recycled so if you put them into the recycle bin they will just go to land fill, what a waste! - they are usually very simple to repair.

Just because it is possible to recycle the co2 container does not mean it is an environmentally friendly thing to do. Melting down then reforming metal uses a lot of energy, energy that usually comes from fossil fuels and adds to climate change. There is nothing environmentally friendly about it, esp when the whole concept of these canisters is based on laziness. If someone can cycle 30 or 40 mile they have the energy to blow a tyre up with a pump.[/QUOTE]

I usually do repair tubes - and what is acceptable in council recycling varies widely from area to area. As far as canisters go, then recovering metal by recycling is far more environmentally friendly than creating new metal from ore, and every little helps.

 

[mjr]

I usually do repair tubes - and what is acceptable in council recycling varies widely from area to area. As far as canisters go, then recovering metal by recycling is far more environmentally friendly than creating new metal from ore, and every little helps.

Not producing the metal waste in the first place is friendlier!

Tubes are accepted in the tyre bins at some recycling centres.