Hows the C02 in your tyres?

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Hows the C02 in your tyres?

Postby theape » Wed Jun 01, 2016 8:25 pm

I learnt recently that if a refill of your tyres is undertaken with CO2 cylinder(s) usually when a puncture has occurred, the tyre needs to be deflated and filled with air at a convenient time. That CO2 will eat your tyres up, I have heard its bad stuff.

Please don't go spreading C02 over the planet all at once, I want my 21% oxygen in air to remain constant.
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Re: Hows the C02 in your tyres?

Postby Bozo » Wed Jun 01, 2016 10:52 pm

Alex

If you ride a lot it I reckon it will make no difference what gas you have in your tyre.

I believe there is very little between having air, nitrogen or carbon dioxide in your tyres. Marginal temperature impacts would only be noticed on race bikes.

The worst component of compressed air is water vapour because, in conjunction with oxygen, it will promote corrosion particularly on rims with tubeless tyres. At least with CO2 canisters you avoid water vapour. Using a hand pump on a day with high humidity puts water vapour into your tyres.

Solution .... wear your tyres out before they perish.

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Re: Hows the C02 in your tyres?

Postby theape » Thu Jun 02, 2016 6:11 am

Ah well said Bozo.
A couple more things to throw in the mix.
If you don't ride much the CO2 will leak out (its to do with the CO2 molecule size compared to an air molecule size) and when you pump the tyre up to correct pressure the problem is partially solved.
Its good we all keep our tyres pumped up.
Cheers
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Re: Hows the C02 in your tyres?

Postby Snaga » Thu Jun 02, 2016 6:44 am

Sounds like a lot of Hot air to me :lol: :lol: :lol: :lol:
"Knowledge is knowing a tomato is a fruit. Wisdom is not putting it in a fruit salad"
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Re: Hows the C02 in your tyres?

Postby Bozo » Thu Jun 02, 2016 6:27 pm

Snaga

It is all very scientific and has to do with molecule shapes.

The Carbon Dioxide molecule is shaped like a straight sausage and when your tyre gets up to barbecue temperature it goes into the atmosphere. They call it a needle shape O = C = O.

Nitrogen is three times slower than oxygen at leaking through rubber but the leakage rates are very slow.

But all of this is irrelevant if you regularly check your tyre pressures and pump your tyres up.

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Re: Hows the C02 in your tyres?

Postby Tyreanser » Mon Jul 11, 2016 9:57 am

Guys,
CO2 maybe a short term fix, best thing for halo butyl rubber (liner & tube) is clean dry air, yes, nitrogen will assist in reducing long term degradation of rubber but we're talking years of operations, M/C tyres don't normally last that long.

As for CO2, yes it will eat rubber, not in the immediate term but in the short term.

Molecule sizes, does anyone know anything about rubber? Only the halo butyl rubber has a tight enough lattice to be impermeable to air. All other rubbers will permit the migration of air molecules through the rubber structure. Why doesn't air migrate back into rubber is a question often missed, yes it does, just try & measure it.

Many studies done in lab conditions, unrealistic.

Clean (filtered oil & particulate free) dry (dried & filtered) is the key to good pressure retention and stable pressure control. Dry? Yes water expands 1603 times from liquid to gas, so as your tyres get hot (m/c tyres don't usually get overly hot unless they're under inflated) the water changes state and drives inflation pressure through the roof.

I've had haulage fleets with 135 psi cold going to 190 + with "shop air", when they changed to clean & dry air the pressures returned to the expected level about 160 psi.

The major tyre companies that supply aviation tyres (most of which are retreaded up to 4 times) have good resources on inflation pressures, ambient temperatures and elevation above sea level.

Now before anyone asks, tyres are like partners, what ever works best for you is the appropriate choice.

Look after your tyres and they'll look after you, ignore them at your own peril.
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Re: Hows the C02 in your tyres?

Postby Chriscoote » Thu Aug 25, 2016 7:20 am

I can verify that if you use CO2 to fill your tyre then you need to deflate it later, refill it a couple times to get rid of the co2.

It will go flat over time as the co2 will leak out due to its nature. Both tubes and tubeless alike will have gas escape. It's better if you just deflate it later and then you won't have that issue again.
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Re: Hows the C02 in your tyres?

Postby wightman » Thu Aug 25, 2016 4:11 pm

The interesting thing about C02, is its average concentration in the atmosphere has increased from about 0.04% to almost 0.06% in the last century. However, with every breath we exhale, it contains a whopping 4% C02 and only 16% 02, so I think we are the single largest contributor to the so called perceived "rise in C02 levels". I wonder why those little canisters are not filed with nitrogen? Something for air Liquide to look at?
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Re: Hows the C02 in your tyres?

Postby Bozo » Thu Aug 25, 2016 6:26 pm

John

CO2 gas bulbs were produced for soda syphons and the use on motorcycles is incidental. It has a higher compressibility than nitrogen so you get more bang for your buck.

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