CO2 inflator - can only get 60 psi from 16g cartridge!

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pfm401

Well-Known Member
Hello

Has anyone any experience of using CO2 cartridges? I bought a Genuine Innovations Proflate Elite the other day and have tried it with Lifeline 16g threaded cartridges (from Wiggle). It's really easy to use, and no leakage, but I seem to need to use 2 to get my preferred 110 psi into my tyres - one cartridge only put 60psi in there (according to my track pump gauge).

I'm running a Gator Skin 23mm hard case, with skinny inner tubes.

My thoughts are:
1. I messed up (I don't think I did as I have the pump pressed firmly on the valve)
2.This is normal
3. Different tyres have different volume requirements - hence a Gator Skin may need more CO2 than a racing tyre

Any advice appreciated!

Thanks, Paul.
 
Having mused on this for a while, I think the only explanation is that you have leakage. I know you say there was none, but how can you know? There is more than enough gas in a 16gm cartridge to inflate a 23mm tyre. probably enough to do two, to 8 BAR or so. Many, many hectopascals are at your disposal.
 

Bollo

Failed Tech Bro
Location
Winch
I did the calcs in a previous thread.....

Which as a physicist got me thinking....

Making some crude assumptions about the cross-sectional area of the inflated tyre and also assuming CO2 is an ideal gas, a back-of-the envelope calculation says that 16g would be enough to hit about 178psi at 20C! (If my maths is right of course - I'll show working out to check if people disagree)

In practice you wouldn't get too near that because of the inevitable leakage when getting the inflator valve on and off, never mind some of the physical assumptions.

I can think of a few times where I've squeezed out one and a half tyres from a single canister, or managed two tyres with a bit of pre-inflation using a mini pump.
 

robgul

Legendary Member
Have to say I have found that different inflators have different performance with the same size 16g CO2 - the inflators that have no control valve (i.e. you attach the inflator to the valve and just turn the cartridge to release the gas) are generally pretty poor with an escape of gas before the seal is made.

The simplest inflators I have (one on each bike) are http://www.weldtite.co.uk/jetvalve/ - you screw the CO2 in firmly and the pin punctures it with minimal if any loss of gas as the rubber o-ring seals - you then just press the spring-loaded head onto the valve and hold it firmly while the gas passes to the tube (with a gloved hand!!!)

I find that a 12g cartridge will inflate a 23mm tyre and I use 16g for my tourer with 28mm tyres - cartridges bought from https://www.tyreinflators.co.uk/index.php?&ccUser= (They deliver by Fedex as Royal Mail bans gas canisters)

Rob
 

Will Spin

Über Member
I've used them now for over 2 years and the only problem I've had was caused by using an inner tube with 42mm valve length instead of 65mm, this meant that the inflator wasn't sealing on the valve properly resulting in some leakage.
 

Broadside

Guru
Location
Fleet, Hants
16g always gives me enough to get the tyre up to good pressure without emptying the cylinder and certainly enough to get home.

Incidentally, my experience if Gatorskins is that you don't want to pump them to max pressure, the harder casing means you can get away with lower pressures, obviously dependant on rider weight but 80psi is usually enough for me. Any harder and they lose compliance and get a bit bouncy on the road.
 

si_c

Guru
Location
Wirral
I got a CO2 inflator that threads onto the presta valve precisely to prevent leakage as I've had it happen once myself. Makes a remarkable difference.
 

Cubist

Still wavin'
Location
Ovver 'thill
Also the track pump gauge method is unreliable. The contents of a 23mm tyre will need to fill the hose from the valve to the gauge to give a reading. This will be a not insignificant percentage of the tyre contents. So the gauge will always read a lot less than the actual pressure of the tyre before you attached the hose.

I discovered this with an air sprung rear suspension shock. Even with a short hose attached, it took such a large percentage of the tiny reservoir to take a reading that the only reliable way to test pressure is on inflating, not by using the pump as a gauge.
 

Smokin Joe

Legendary Member
I've used Co2 inflators in the past, but the potential hassle such as a leaking seal (They all do eventually) and the need to carry a back up hand pump (You'll be sorry if you don't) make them more trouble than they are worth. Especially now as mini pumps like the Lezyne are so good they put some full size pumps to shame.
 

martint235

Dog on a bike
Location
Welling
Also the track pump gauge method is unreliable. The contents of a 23mm tyre will need to fill the hose from the valve to the gauge to give a reading. This will be a not insignificant percentage of the tyre contents. So the gauge will always read a lot less than the actual pressure of the tyre before you attached the hose.

I discovered this with an air sprung rear suspension shock. Even with a short hose attached, it took such a large percentage of the tiny reservoir to take a reading that the only reliable way to test pressure is on inflating, not by using the pump as a gauge.
That's what I was going to say. My co2 pump gets the duranos as hard as I want them, around 125psi but whenever I attach a track pump it reads around 80 due to filling around 2 or 3 feet of hose
 

andrew_s

Legendary Member
Location
Gloucester
That's what I was going to say. My co2 pump gets the duranos as hard as I want them, around 125psi but whenever I attach a track pump it reads around 80 due to filling around 2 or 3 feet of hose
If you take a track pump hose as being 0.75 cm internal diameter and 1 m long, and a 23 mm tyre as being 23mm across and 2 m round, the pressure loss due to filling the hose would be 56/1058 = 5% - i.e. 125psi down to 119 psi.
Your 80 psi will be a combination of (a) overestimating the initial pressure, and (b) the gas leaking out of the tyre before you measure the pressure (or possibly a dodgy gauge).

Inner tubes are a lot more porous to CO2 than they are to air, and a day is plenty of time to lose enough gas to take the pressure down that far.
 
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